Is this scheme reasonable?

[Phil Hobbs]

On 05/11/2017 04:07 PM, John Larkin wrote:

On Wed, 10 May 2017 13:50:05 -0700, etpm@whidbey.com wrote:

On Wed, 10 May 2017 11:31:40 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:

On Wed, 10 May 2017 09:57:21 -0700, etpm@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

A conventional cap, no. Maybe a super expensive supercap.

I wouldn't want an electronic trash can. All that cheap, badly
programmed microprocessor/LCD appliance junk will break in a couple of
years, and be annoying meanwhile.

*SIX* AA cells? How long do they last?
Thanks for the quick responses everyone. It looks like rechargeable
cells are really the best way to go. The regular cells last about 3
months. I hate the garbage can. I hate throwing batteries in the
recycle bin. I hate the garbage can. It was advertised as motion
sensitive. It is not. It senses reflected IR, not motion. So if the
damn sensor is covered with IR reflective material the lid stays open.
Did you know that some clear plastic sheet reflects IR? Did I say I
hate the garbage can? Unfortunately for now it is the best solution.
Though a foot operated model is in the future right now it just won't
work.
Thanks Again,
Eric

We have a nice kitchen trash can that opens when you step on a little
pedal thing.

Would someone there have a problem with the mechanical version?
Wheelchair or something?

For a serious engineering project, throw away the electronics and
drive the lid motor yourself.

Sure! Use a Cortex M4 and the OP can have a trash can that has to be
rebooted periodically!

O tempora! O mores!

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

[default]

On Sat, 13 May 2017 08:35:23 -0700, John Larkin
<jjlarkin@highlandtechnology.com> wrote:

On Fri, 12 May 2017 06:47:01 -0400, default <default@defaulter.net
wrote:

On Fri, 12 May 2017 10:47:54 +0200, o pere o <me@somewhere.net> wrote:

On 11/05/17 00:42, Phil Hobbs wrote:
On 05/10/2017 02:31 PM, John Larkin wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

A conventional cap, no. Maybe a super expensive supercap.

I wouldn't want an electronic trash can. All that cheap, badly
programmed microprocessor/LCD appliance junk will break in a couple of
years, and be annoying meanwhile.

*SIX* AA cells? How long do they last?



A couple of supercaps in series might work fine. For instance,
SCMT22C505MRBA0 AVX CAPACITOR 5F 20% 5V 0.065ohms $5.23000 in onesies
from Digikey.

Two of those in series, with a TL431 across each one (set for 4.8V or
so) to equalize the voltage, plus a charger with about a 50 mA current
limit ought to work, I should think.

Cheers

Phil Hobbs


Is there data on leakage or self-discharge of these beasts? The
datasheet just says "low leakage current" and this could just mean
anything...

Pere

The caps I'm using give the leakage at .16 ma.

http://www.illinoiscapacitor.com/ic_search/super_products_detail.aspx?icpartnumber=700020


50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

Damn good caps for what I'm doing with them though...

 

[Tim Wescott]

On Thu, 11 May 2017 13:10:36 -0400, rickman wrote:

On 5/11/2017 11:32 AM, Tim Wescott wrote:
On Wed, 10 May 2017 18:13:26 -0400, rickman wrote:

On 5/10/2017 1:52 PM, Tim Wescott wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm wrote:

I have an automatic opening trash can in the kitchen that runs off
of batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power
it could deliver. This makes sense. I don't want to use a bigger
wall wart and I don't want to have betteries in it all the time to
provide the current. I'm thinking instead of using a capacitor. If
the current and voltage draw as well as the duration to open the lid
is measured can that not be used to calculate the minimum size
capacitor? And if not excessive maybe a cap that would open the lid
three or four times in a row could be used in place of the 6 AA
cells it uses now. Reasonable?
Thanks,
Eric

This is kind of a repeat of what Rick said, from a different point of
view:

For the amount of energy stored, caps are BIG. And a capacitor's
voltage falls as it delivers energy -- by definition. If it doesn't,
it's not a capacitor.

Rechargeable batteries are much smaller than caps -- and it's what
the thing's designed for anyway. The easiest thing to do, which
should be reliable, is to populate the battery tray with rechargable
NiMH cells, then put a charger on it that runs at a trickle rate
(i.e., 50mA for every 1000mAh of capacity). That _should_ let the
batteries last a good long time, but whether it'll stay charged is
kind of up in the air (or maybe it'll work fin normally but not on
Thanksgiving or Christmas).

Make the charger from a wall-wart and a resistor.

The only other way I can think of to make this work "better" is with
a smart charger -- and then you're messing with some pretty fancy
electronics to keep the batteries happy. So -- probably not a good
idea.

Finally -- have you considered an old fashioned, works just fine,
_mechanical_ covered trash can?

I think you have this pretty much backwards. A "smart" battery
charger is the only real way to go if you want the batteries to last.
The "trickle" charger may keep the batteries up given that most people
don't use such a trash can for long periods, but once rechargeables
are charged, they don't want more current unless they are lead acid.
I didn't look it up, so do you know that NiMH will take a trickle
charge without damage? I don't think I've heard of that.

Proper charging electronics doesn't need to be hard to design or use.

I know Eric from these groups, and I'm assuming that he doesn't want to
run out and design a PCB just for a trash can.

You seem to be unable to think outside the box many times. I can't
imagine building a PCB for a project like this. I'd use an expression
involving cats, but it is prohibited in this house.

So what specific suggestion do you have, oh master of practicality?

--
www.wescottdesign.com

 

[rickman]

On 5/13/2017 2:26 PM, Tim Wescott wrote:

On Thu, 11 May 2017 13:10:36 -0400, rickman wrote:

On 5/11/2017 11:32 AM, Tim Wescott wrote:
On Wed, 10 May 2017 18:13:26 -0400, rickman wrote:

On 5/10/2017 1:52 PM, Tim Wescott wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm wrote:

I have an automatic opening trash can in the kitchen that runs off
of batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power
it could deliver. This makes sense. I don't want to use a bigger
wall wart and I don't want to have betteries in it all the time to
provide the current. I'm thinking instead of using a capacitor. If
the current and voltage draw as well as the duration to open the lid
is measured can that not be used to calculate the minimum size
capacitor? And if not excessive maybe a cap that would open the lid
three or four times in a row could be used in place of the 6 AA
cells it uses now. Reasonable?
Thanks,
Eric

This is kind of a repeat of what Rick said, from a different point of
view:

For the amount of energy stored, caps are BIG. And a capacitor's
voltage falls as it delivers energy -- by definition. If it doesn't,
it's not a capacitor.

Rechargeable batteries are much smaller than caps -- and it's what
the thing's designed for anyway. The easiest thing to do, which
should be reliable, is to populate the battery tray with rechargable
NiMH cells, then put a charger on it that runs at a trickle rate
(i.e., 50mA for every 1000mAh of capacity). That _should_ let the
batteries last a good long time, but whether it'll stay charged is
kind of up in the air (or maybe it'll work fin normally but not on
Thanksgiving or Christmas).

Make the charger from a wall-wart and a resistor.

The only other way I can think of to make this work "better" is with
a smart charger -- and then you're messing with some pretty fancy
electronics to keep the batteries happy. So -- probably not a good
idea.

Finally -- have you considered an old fashioned, works just fine,
_mechanical_ covered trash can?

I think you have this pretty much backwards. A "smart" battery
charger is the only real way to go if you want the batteries to last.
The "trickle" charger may keep the batteries up given that most people
don't use such a trash can for long periods, but once rechargeables
are charged, they don't want more current unless they are lead acid.
I didn't look it up, so do you know that NiMH will take a trickle
charge without damage? I don't think I've heard of that.

Proper charging electronics doesn't need to be hard to design or use.

I know Eric from these groups, and I'm assuming that he doesn't want to
run out and design a PCB just for a trash can.

You seem to be unable to think outside the box many times. I can't
imagine building a PCB for a project like this. I'd use an expression
involving cats, but it is prohibited in this house.

So what specific suggestion do you have, oh master of practicality?

Really? You can't think of any board which could be bought to do this?
Or a prototype can be made by any of many choices which don't require a
PCB to be made. Do you really need a tutorial?

This is a one off and a fairly simple circuit. Not something that
requires a custom PCB really.

--

Rick C

 

[Tim Wescott]

On Sat, 13 May 2017 14:31:09 -0400, rickman wrote:

On 5/13/2017 2:26 PM, Tim Wescott wrote:
On Thu, 11 May 2017 13:10:36 -0400, rickman wrote:

On 5/11/2017 11:32 AM, Tim Wescott wrote:
On Wed, 10 May 2017 18:13:26 -0400, rickman wrote:

On 5/10/2017 1:52 PM, Tim Wescott wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm wrote:

I have an automatic opening trash can in the kitchen that runs
off of batteries. I wanna run it with a wall wart. When the lid
opens it draws more power than the 750 mA wall wart I tried using
to power it could deliver. This makes sense. I don't want to use a
bigger wall wart and I don't want to have betteries in it all the
time to provide the current. I'm thinking instead of using a
capacitor. If the current and voltage draw as well as the duration
to open the lid is measured can that not be used to calculate the
minimum size capacitor? And if not excessive maybe a cap that
would open the lid three or four times in a row could be used in
place of the 6 AA cells it uses now. Reasonable?
Thanks,
Eric

This is kind of a repeat of what Rick said, from a different point
of view:

For the amount of energy stored, caps are BIG. And a capacitor's
voltage falls as it delivers energy -- by definition. If it
doesn't,
it's not a capacitor.

Rechargeable batteries are much smaller than caps -- and it's what
the thing's designed for anyway. The easiest thing to do, which
should be reliable, is to populate the battery tray with
rechargable NiMH cells, then put a charger on it that runs at a
trickle rate (i.e., 50mA for every 1000mAh of capacity). That
_should_ let the batteries last a good long time, but whether it'll
stay charged is kind of up in the air (or maybe it'll work fin
normally but not on Thanksgiving or Christmas).

Make the charger from a wall-wart and a resistor.

The only other way I can think of to make this work "better" is
with a smart charger -- and then you're messing with some pretty
fancy electronics to keep the batteries happy. So -- probably not
a good idea.

Finally -- have you considered an old fashioned, works just fine,
_mechanical_ covered trash can?

I think you have this pretty much backwards. A "smart" battery
charger is the only real way to go if you want the batteries to
last. The "trickle" charger may keep the batteries up given that
most people don't use such a trash can for long periods, but once
rechargeables are charged, they don't want more current unless they
are lead acid. I didn't look it up, so do you know that NiMH will
take a trickle charge without damage? I don't think I've heard of
that.

Proper charging electronics doesn't need to be hard to design or
use.

I know Eric from these groups, and I'm assuming that he doesn't want
to run out and design a PCB just for a trash can.

You seem to be unable to think outside the box many times. I can't
imagine building a PCB for a project like this. I'd use an expression
involving cats, but it is prohibited in this house.

So what specific suggestion do you have, oh master of practicality?

Really? You can't think of any board which could be bought to do this?
Or a prototype can be made by any of many choices which don't require a
PCB to be made. Do you really need a tutorial?

This is a one off and a fairly simple circuit. Not something that
requires a custom PCB really.

Well, if it's so damned easy, provide the tutorial just to spite me!
It'll help Eric, which is _my_ goal.

Part numbers! Ebay links! C'mon -- you yourself say it's a snap!

What does it mean to say "oh that's easy, stupid!" and then refuse to
demonstrate?

--
www.wescottdesign.com

 

[rickman]

On 5/13/2017 2:42 PM, Tim Wescott wrote:

On Sat, 13 May 2017 14:31:09 -0400, rickman wrote:

On 5/13/2017 2:26 PM, Tim Wescott wrote:
On Thu, 11 May 2017 13:10:36 -0400, rickman wrote:

On 5/11/2017 11:32 AM, Tim Wescott wrote:
On Wed, 10 May 2017 18:13:26 -0400, rickman wrote:

On 5/10/2017 1:52 PM, Tim Wescott wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm wrote:

I have an automatic opening trash can in the kitchen that runs
off of batteries. I wanna run it with a wall wart. When the lid
opens it draws more power than the 750 mA wall wart I tried using
to power it could deliver. This makes sense. I don't want to use a
bigger wall wart and I don't want to have betteries in it all the
time to provide the current. I'm thinking instead of using a
capacitor. If the current and voltage draw as well as the duration
to open the lid is measured can that not be used to calculate the
minimum size capacitor? And if not excessive maybe a cap that
would open the lid three or four times in a row could be used in
place of the 6 AA cells it uses now. Reasonable?
Thanks,
Eric

This is kind of a repeat of what Rick said, from a different point
of view:

For the amount of energy stored, caps are BIG. And a capacitor's
voltage falls as it delivers energy -- by definition. If it
doesn't,
it's not a capacitor.

Rechargeable batteries are much smaller than caps -- and it's what
the thing's designed for anyway. The easiest thing to do, which
should be reliable, is to populate the battery tray with
rechargable NiMH cells, then put a charger on it that runs at a
trickle rate (i.e., 50mA for every 1000mAh of capacity). That
_should_ let the batteries last a good long time, but whether it'll
stay charged is kind of up in the air (or maybe it'll work fin
normally but not on Thanksgiving or Christmas).

Make the charger from a wall-wart and a resistor.

The only other way I can think of to make this work "better" is
with a smart charger -- and then you're messing with some pretty
fancy electronics to keep the batteries happy. So -- probably not
a good idea.

Finally -- have you considered an old fashioned, works just fine,
_mechanical_ covered trash can?

I think you have this pretty much backwards. A "smart" battery
charger is the only real way to go if you want the batteries to
last. The "trickle" charger may keep the batteries up given that
most people don't use such a trash can for long periods, but once
rechargeables are charged, they don't want more current unless they
are lead acid. I didn't look it up, so do you know that NiMH will
take a trickle charge without damage? I don't think I've heard of
that.

Proper charging electronics doesn't need to be hard to design or
use.

I know Eric from these groups, and I'm assuming that he doesn't want
to run out and design a PCB just for a trash can.

You seem to be unable to think outside the box many times. I can't
imagine building a PCB for a project like this. I'd use an expression
involving cats, but it is prohibited in this house.

So what specific suggestion do you have, oh master of practicality?

Really? You can't think of any board which could be bought to do this?
Or a prototype can be made by any of many choices which don't require a
PCB to be made. Do you really need a tutorial?

This is a one off and a fairly simple circuit. Not something that
requires a custom PCB really.

Well, if it's so damned easy, provide the tutorial just to spite me!
It'll help Eric, which is _my_ goal.

Part numbers! Ebay links! C'mon -- you yourself say it's a snap!

What does it mean to say "oh that's easy, stupid!" and then refuse to
demonstrate?

Why are you so upset? You said it required making a PCB and I said it
doesn't. Now I have to go out and build the damn thing to prove my
point? You are a trip.

At this point you are just trolling.

--

Rick C

 

[Tim Wescott]

On Sat, 13 May 2017 14:44:27 -0400, rickman wrote:

On 5/13/2017 2:42 PM, Tim Wescott wrote:
On Sat, 13 May 2017 14:31:09 -0400, rickman wrote:

On 5/13/2017 2:26 PM, Tim Wescott wrote:
On Thu, 11 May 2017 13:10:36 -0400, rickman wrote:

On 5/11/2017 11:32 AM, Tim Wescott wrote:
On Wed, 10 May 2017 18:13:26 -0400, rickman wrote:

On 5/10/2017 1:52 PM, Tim Wescott wrote:

Proper charging electronics doesn't need to be hard to design or
use.

This is a one off and a fairly simple circuit. Not something that
requires a custom PCB really.

Well, if it's so damned easy, provide the tutorial just to spite me!
It'll help Eric, which is _my_ goal.

Part numbers! Ebay links! C'mon -- you yourself say it's a snap!

What does it mean to say "oh that's easy, stupid!" and then refuse to
demonstrate?

Why are you so upset? You said it required making a PCB and I said it
doesn't. Now I have to go out and build the damn thing to prove my
point? You are a trip.

At this point you are just trolling.

I'm not upset. I'm amused.

But it's really time to put your money where your mouth is, dude, and
show how you can do this. Because -- by your own words it's not hard.
And it'll benefit _everyone_.

Just a block diagram of a charger that's more intelligent than a wall-
wart and a resistor (because that's what a trickle charger is). Or a
product he can buy that'll do it. That's all -- no need to show us how
to implement it sans PCB.

--
www.wescottdesign.com

 

[rickman]

On 5/13/2017 3:28 PM, Tim Wescott wrote:

On Sat, 13 May 2017 14:44:27 -0400, rickman wrote:

On 5/13/2017 2:42 PM, Tim Wescott wrote:
On Sat, 13 May 2017 14:31:09 -0400, rickman wrote:

On 5/13/2017 2:26 PM, Tim Wescott wrote:
On Thu, 11 May 2017 13:10:36 -0400, rickman wrote:

On 5/11/2017 11:32 AM, Tim Wescott wrote:
On Wed, 10 May 2017 18:13:26 -0400, rickman wrote:

On 5/10/2017 1:52 PM, Tim Wescott wrote:

Proper charging electronics doesn't need to be hard to design or
use.


This is a one off and a fairly simple circuit. Not something that
requires a custom PCB really.

Well, if it's so damned easy, provide the tutorial just to spite me!
It'll help Eric, which is _my_ goal.

Part numbers! Ebay links! C'mon -- you yourself say it's a snap!

What does it mean to say "oh that's easy, stupid!" and then refuse to
demonstrate?

Why are you so upset? You said it required making a PCB and I said it
doesn't. Now I have to go out and build the damn thing to prove my
point? You are a trip.

At this point you are just trolling.

I'm not upset. I'm amused.

But it's really time to put your money where your mouth is, dude, and
show how you can do this. Because -- by your own words it's not hard.
And it'll benefit _everyone_.

Just a block diagram of a charger that's more intelligent than a wall-
wart and a resistor (because that's what a trickle charger is). Or a
product he can buy that'll do it. That's all -- no need to show us how
to implement it sans PCB.

Get me the trash can.

--

Rick C

 

[Bob Engelhardt]

On 5/13/2017 1:47 PM, default wrote:

On Sat, 13 May 2017 08:35:23 -0700, John Larkin
50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

Damn good caps for what I'm doing with them though...

50F x 2.7v = 135C = 135As = 135/3600Ah = 0.0374Ah

50.625Wh /.0375Ah = 1350v

Point slipped 3 places, I think. .05625Wh

 

[Bob Engelhardt]

On 5/13/2017 6:00 PM, Bob Engelhardt wrote:

On 5/13/2017 1:47 PM, default wrote:
On Sat, 13 May 2017 08:35:23 -0700, John Larkin
50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

Damn good caps for what I'm doing with them though...


50F x 2.7v = 135C = 135As = 135/3600Ah = 0.0374Ah

50.625Wh /.0375Ah = 1350v

Point slipped 3 places, I think. .05625Wh

Oops ... .50625 ... there's your 1/2Wh "default"

 

[default]

On Sun, 14 May 2017 01:07:57 -0400, Bob Engelhardt
<BobEngelhardt@comcast.net> wrote:

On 5/13/2017 6:00 PM, Bob Engelhardt wrote:
On 5/13/2017 1:47 PM, default wrote:
On Sat, 13 May 2017 08:35:23 -0700, John Larkin
50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

Damn good caps for what I'm doing with them though...


50F x 2.7v = 135C = 135As = 135/3600Ah = 0.0374Ah

50.625Wh /.0375Ah = 1350v

Point slipped 3 places, I think. .05625Wh

Oops ... .50625 ... there's your 1/2Wh "default"

I think you had it right at .05 Watt Hours

 

[Jasen Betts]

On 2017-05-13, default <default@defaulter.net> wrote:

On Sat, 13 May 2017 08:35:23 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Fri, 12 May 2017 06:47:01 -0400, default <default@defaulter.net
wrote:

On Fri, 12 May 2017 10:47:54 +0200, o pere o <me@somewhere.net> wrote:

On 11/05/17 00:42, Phil Hobbs wrote:
On 05/10/2017 02:31 PM, John Larkin wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

A conventional cap, no. Maybe a super expensive supercap.

I wouldn't want an electronic trash can. All that cheap, badly
programmed microprocessor/LCD appliance junk will break in a couple of
years, and be annoying meanwhile.

*SIX* AA cells? How long do they last?



A couple of supercaps in series might work fine. For instance,
SCMT22C505MRBA0 AVX CAPACITOR 5F 20% 5V 0.065ohms $5.23000 in onesies
from Digikey.

Two of those in series, with a TL431 across each one (set for 4.8V or
so) to equalize the voltage, plus a charger with about a 50 mA current
limit ought to work, I should think.

Cheers

Phil Hobbs


Is there data on leakage or self-discharge of these beasts? The
datasheet just says "low leakage current" and this could just mean
anything...

Pere

The caps I'm using give the leakage at .16 ma.

http://www.illinoiscapacitor.com/ic_search/super_products_detail.aspx?icpartnumber=700020


50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

more like 3 decimal places, 0.5*C*V*V/3600

--
This email has not been checked by half-arsed antivirus software

 

[default]

On 18 May 2017 06:00:58 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2017-05-13, default <default@defaulter.net> wrote:
On Sat, 13 May 2017 08:35:23 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Fri, 12 May 2017 06:47:01 -0400, default <default@defaulter.net
wrote:

On Fri, 12 May 2017 10:47:54 +0200, o pere o <me@somewhere.net> wrote:

On 11/05/17 00:42, Phil Hobbs wrote:
On 05/10/2017 02:31 PM, John Larkin wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

A conventional cap, no. Maybe a super expensive supercap.

I wouldn't want an electronic trash can. All that cheap, badly
programmed microprocessor/LCD appliance junk will break in a couple of
years, and be annoying meanwhile.

*SIX* AA cells? How long do they last?



A couple of supercaps in series might work fine. For instance,
SCMT22C505MRBA0 AVX CAPACITOR 5F 20% 5V 0.065ohms $5.23000 in onesies
from Digikey.

Two of those in series, with a TL431 across each one (set for 4.8V or
so) to equalize the voltage, plus a charger with about a 50 mA current
limit ought to work, I should think.

Cheers

Phil Hobbs


Is there data on leakage or self-discharge of these beasts? The
datasheet just says "low leakage current" and this could just mean
anything...

Pere

The caps I'm using give the leakage at .16 ma.

http://www.illinoiscapacitor.com/ic_search/super_products_detail.aspx?icpartnumber=700020


50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

more like 3 decimal places, 0.5*C*V*V/3600

I agree. Did the math and posted as much on 5/14.

I'm thinking they mistakenly used some "one size fits all" or
watt-hours per X farads.

In a related experiment... I'm temporarily using some Maxwell "D-cell"
series caps to power the buoy flasher that got 6 months of use from
3-AA alkaline cells, switching to a solar charged, 175 F, 3 V system
(using caps that cost $15 each). That system is flashing the strobe,
for 8 days on the charge it can get in one day. (cover the solar
cells with aluminum foil and wait till it dies).

So a pair of the $1.29 50 F caps should easily last a day, or perhaps
just use one 50 F and go with 2.5V. (specs on the controller that I'm
using says it works down to 2.2V, and it seems to recover and start
running it's program from the beginning when the voltage gets to about
2V)

The buoy that I'm illuminating belongs to the city.. So I have to keep
the cost low in case they discover that I've modified the buoy and
decide to remove my strobe, or vandals (or Visigoths) make it to that
end of the lake and steal or destroy it...

It's become a "thing" to tweak the buoy with something different each
year. I go kayaking at 3:30 AM to avoid the summer heat, but it's a
challenge to find ways to see where I'm going in the dark on a lake
that's 2 miles long.

Radio beacon? or perhaps a super strobe that I can trigger from 2
miles away?

 

[John Larkin]

On Thu, 18 May 2017 07:41:04 -0400, default <default@defaulter.net>
wrote:

On 18 May 2017 06:00:58 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2017-05-13, default <default@defaulter.net> wrote:
On Sat, 13 May 2017 08:35:23 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Fri, 12 May 2017 06:47:01 -0400, default <default@defaulter.net
wrote:

On Fri, 12 May 2017 10:47:54 +0200, o pere o <me@somewhere.net> wrote:

On 11/05/17 00:42, Phil Hobbs wrote:
On 05/10/2017 02:31 PM, John Larkin wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

A conventional cap, no. Maybe a super expensive supercap.

I wouldn't want an electronic trash can. All that cheap, badly
programmed microprocessor/LCD appliance junk will break in a couple of
years, and be annoying meanwhile.

*SIX* AA cells? How long do they last?



A couple of supercaps in series might work fine. For instance,
SCMT22C505MRBA0 AVX CAPACITOR 5F 20% 5V 0.065ohms $5.23000 in onesies
from Digikey.

Two of those in series, with a TL431 across each one (set for 4.8V or
so) to equalize the voltage, plus a charger with about a 50 mA current
limit ought to work, I should think.

Cheers

Phil Hobbs


Is there data on leakage or self-discharge of these beasts? The
datasheet just says "low leakage current" and this could just mean
anything...

Pere

The caps I'm using give the leakage at .16 ma.

http://www.illinoiscapacitor.com/ic_search/super_products_detail.aspx?icpartnumber=700020


50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

more like 3 decimal places, 0.5*C*V*V/3600

I agree. Did the math and posted as much on 5/14.

I'm thinking they mistakenly used some "one size fits all" or
watt-hours per X farads.

In a related experiment... I'm temporarily using some Maxwell "D-cell"
series caps to power the buoy flasher that got 6 months of use from
3-AA alkaline cells, switching to a solar charged, 175 F, 3 V system
(using caps that cost $15 each). That system is flashing the strobe,
for 8 days on the charge it can get in one day. (cover the solar
cells with aluminum foil and wait till it dies).

So a pair of the $1.29 50 F caps should easily last a day, or perhaps
just use one 50 F and go with 2.5V. (specs on the controller that I'm
using says it works down to 2.2V, and it seems to recover and start
running it's program from the beginning when the voltage gets to about
2V)

The buoy that I'm illuminating belongs to the city.. So I have to keep
the cost low in case they discover that I've modified the buoy and
decide to remove my strobe, or vandals (or Visigoths) make it to that
end of the lake and steal or destroy it...

It's become a "thing" to tweak the buoy with something different each
year. I go kayaking at 3:30 AM to avoid the summer heat, but it's a
challenge to find ways to see where I'm going in the dark on a lake
that's 2 miles long.

Radio beacon? or perhaps a super strobe that I can trigger from 2
miles away?

Tritium light?

Strontium aluminate paint?

Both would be fairly short range visibility. For longer range, why not
use GPS?


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[default]

On Thu, 18 May 2017 08:43:17 -0700, John Larkin
<jjlarkin@highlandtechnology.com> wrote:

On Thu, 18 May 2017 07:41:04 -0400, default <default@defaulter.net
wrote:

On 18 May 2017 06:00:58 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2017-05-13, default <default@defaulter.net> wrote:
On Sat, 13 May 2017 08:35:23 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Fri, 12 May 2017 06:47:01 -0400, default <default@defaulter.net
wrote:

On Fri, 12 May 2017 10:47:54 +0200, o pere o <me@somewhere.net> wrote:

On 11/05/17 00:42, Phil Hobbs wrote:
On 05/10/2017 02:31 PM, John Larkin wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

A conventional cap, no. Maybe a super expensive supercap.

I wouldn't want an electronic trash can. All that cheap, badly
programmed microprocessor/LCD appliance junk will break in a couple of
years, and be annoying meanwhile.

*SIX* AA cells? How long do they last?



A couple of supercaps in series might work fine. For instance,
SCMT22C505MRBA0 AVX CAPACITOR 5F 20% 5V 0.065ohms $5.23000 in onesies
from Digikey.

Two of those in series, with a TL431 across each one (set for 4.8V or
so) to equalize the voltage, plus a charger with about a 50 mA current
limit ought to work, I should think.

Cheers

Phil Hobbs


Is there data on leakage or self-discharge of these beasts? The
datasheet just says "low leakage current" and this could just mean
anything...

Pere

The caps I'm using give the leakage at .16 ma.

http://www.illinoiscapacitor.com/ic_search/super_products_detail.aspx?icpartnumber=700020


50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

more like 3 decimal places, 0.5*C*V*V/3600

I agree. Did the math and posted as much on 5/14.

I'm thinking they mistakenly used some "one size fits all" or
watt-hours per X farads.

In a related experiment... I'm temporarily using some Maxwell "D-cell"
series caps to power the buoy flasher that got 6 months of use from
3-AA alkaline cells, switching to a solar charged, 175 F, 3 V system
(using caps that cost $15 each). That system is flashing the strobe,
for 8 days on the charge it can get in one day. (cover the solar
cells with aluminum foil and wait till it dies).

So a pair of the $1.29 50 F caps should easily last a day, or perhaps
just use one 50 F and go with 2.5V. (specs on the controller that I'm
using says it works down to 2.2V, and it seems to recover and start
running it's program from the beginning when the voltage gets to about
2V)

The buoy that I'm illuminating belongs to the city.. So I have to keep
the cost low in case they discover that I've modified the buoy and
decide to remove my strobe, or vandals (or Visigoths) make it to that
end of the lake and steal or destroy it...

It's become a "thing" to tweak the buoy with something different each
year. I go kayaking at 3:30 AM to avoid the summer heat, but it's a
challenge to find ways to see where I'm going in the dark on a lake
that's 2 miles long.

Radio beacon? or perhaps a super strobe that I can trigger from 2
miles away?

Tritium light?

Strontium aluminate paint?

Both would be fairly short range visibility. For longer range, why not
use GPS?

Tried that too. Got a Magellan "waterproof" little hand-held thingee.
Cost a small fortune and wasn't waterproof enough to take dunking in
water. Since they stopped the extended warranty plan, I stopped
taking it kayaking. It was hard to read too...

The nice thing about it was when I was on a new creek, I could see my
progress.

 

On Wednesday, May 10, 2017 at 9:50:41 AM UTC-7, et...@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

Nah, go for a 2-stroke gasoline-powered trash can

I wonder if this could work.
https://www.walmart.com/ip/Scosche-500K-Micro-Farad-Capacitor/46997835

Michael

 

[rickman]

On 5/19/2017 6:55 AM, default wrote:

On Thu, 18 May 2017 08:43:17 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Thu, 18 May 2017 07:41:04 -0400, default <default@defaulter.net
wrote:

On 18 May 2017 06:00:58 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2017-05-13, default <default@defaulter.net> wrote:
On Sat, 13 May 2017 08:35:23 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Fri, 12 May 2017 06:47:01 -0400, default <default@defaulter.net
wrote:

On Fri, 12 May 2017 10:47:54 +0200, o pere o <me@somewhere.net> wrote:

On 11/05/17 00:42, Phil Hobbs wrote:
On 05/10/2017 02:31 PM, John Larkin wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

A conventional cap, no. Maybe a super expensive supercap.

I wouldn't want an electronic trash can. All that cheap, badly
programmed microprocessor/LCD appliance junk will break in a couple of
years, and be annoying meanwhile.

*SIX* AA cells? How long do they last?



A couple of supercaps in series might work fine. For instance,
SCMT22C505MRBA0 AVX CAPACITOR 5F 20% 5V 0.065ohms $5.23000 in onesies
from Digikey.

Two of those in series, with a TL431 across each one (set for 4.8V or
so) to equalize the voltage, plus a charger with about a 50 mA current
limit ought to work, I should think.

Cheers

Phil Hobbs


Is there data on leakage or self-discharge of these beasts? The
datasheet just says "low leakage current" and this could just mean
anything...

Pere

The caps I'm using give the leakage at .16 ma.

http://www.illinoiscapacitor.com/ic_search/super_products_detail.aspx?icpartnumber=700020


50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

more like 3 decimal places, 0.5*C*V*V/3600

I agree. Did the math and posted as much on 5/14.

I'm thinking they mistakenly used some "one size fits all" or
watt-hours per X farads.

In a related experiment... I'm temporarily using some Maxwell "D-cell"
series caps to power the buoy flasher that got 6 months of use from
3-AA alkaline cells, switching to a solar charged, 175 F, 3 V system
(using caps that cost $15 each). That system is flashing the strobe,
for 8 days on the charge it can get in one day. (cover the solar
cells with aluminum foil and wait till it dies).

So a pair of the $1.29 50 F caps should easily last a day, or perhaps
just use one 50 F and go with 2.5V. (specs on the controller that I'm
using says it works down to 2.2V, and it seems to recover and start
running it's program from the beginning when the voltage gets to about
2V)

The buoy that I'm illuminating belongs to the city.. So I have to keep
the cost low in case they discover that I've modified the buoy and
decide to remove my strobe, or vandals (or Visigoths) make it to that
end of the lake and steal or destroy it...

It's become a "thing" to tweak the buoy with something different each
year. I go kayaking at 3:30 AM to avoid the summer heat, but it's a
challenge to find ways to see where I'm going in the dark on a lake
that's 2 miles long.

Radio beacon? or perhaps a super strobe that I can trigger from 2
miles away?

Tritium light?

Strontium aluminate paint?

Both would be fairly short range visibility. For longer range, why not
use GPS?

Tried that too. Got a Magellan "waterproof" little hand-held thingee.
Cost a small fortune and wasn't waterproof enough to take dunking in
water. Since they stopped the extended warranty plan, I stopped
taking it kayaking. It was hard to read too...

The nice thing about it was when I was on a new creek, I could see my
progress.

They are rated as waterproof, but not very waterproof. I've yet to find
one that will survive on the deck of a kayak for more than a season.
Sooner or later they leak and crap out.

I've never had any trouble seeing where I'm going. Even starlight is
enough to navigate. Once the stars are gone you have to know your
terrain (aquaine?) pretty well though. Overcast makes for interesting
trips though. I take you paddle where there is no illumination from
houses and such? Even a single porch light in the distance can provide
orientation.

--

Rick C

 

[John Larkin]

On Fri, 19 May 2017 06:55:25 -0400, default <default@defaulter.net>
wrote:

On Thu, 18 May 2017 08:43:17 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Thu, 18 May 2017 07:41:04 -0400, default <default@defaulter.net
wrote:

On 18 May 2017 06:00:58 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2017-05-13, default <default@defaulter.net> wrote:
On Sat, 13 May 2017 08:35:23 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Fri, 12 May 2017 06:47:01 -0400, default <default@defaulter.net
wrote:

On Fri, 12 May 2017 10:47:54 +0200, o pere o <me@somewhere.net> wrote:

On 11/05/17 00:42, Phil Hobbs wrote:
On 05/10/2017 02:31 PM, John Larkin wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

A conventional cap, no. Maybe a super expensive supercap.

I wouldn't want an electronic trash can. All that cheap, badly
programmed microprocessor/LCD appliance junk will break in a couple of
years, and be annoying meanwhile.

*SIX* AA cells? How long do they last?



A couple of supercaps in series might work fine. For instance,
SCMT22C505MRBA0 AVX CAPACITOR 5F 20% 5V 0.065ohms $5.23000 in onesies
from Digikey.

Two of those in series, with a TL431 across each one (set for 4.8V or
so) to equalize the voltage, plus a charger with about a 50 mA current
limit ought to work, I should think.

Cheers

Phil Hobbs


Is there data on leakage or self-discharge of these beasts? The
datasheet just says "low leakage current" and this could just mean
anything...

Pere

The caps I'm using give the leakage at .16 ma.

http://www.illinoiscapacitor.com/ic_search/super_products_detail.aspx?icpartnumber=700020


50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

more like 3 decimal places, 0.5*C*V*V/3600

I agree. Did the math and posted as much on 5/14.

I'm thinking they mistakenly used some "one size fits all" or
watt-hours per X farads.

In a related experiment... I'm temporarily using some Maxwell "D-cell"
series caps to power the buoy flasher that got 6 months of use from
3-AA alkaline cells, switching to a solar charged, 175 F, 3 V system
(using caps that cost $15 each). That system is flashing the strobe,
for 8 days on the charge it can get in one day. (cover the solar
cells with aluminum foil and wait till it dies).

So a pair of the $1.29 50 F caps should easily last a day, or perhaps
just use one 50 F and go with 2.5V. (specs on the controller that I'm
using says it works down to 2.2V, and it seems to recover and start
running it's program from the beginning when the voltage gets to about
2V)

The buoy that I'm illuminating belongs to the city.. So I have to keep
the cost low in case they discover that I've modified the buoy and
decide to remove my strobe, or vandals (or Visigoths) make it to that
end of the lake and steal or destroy it...

It's become a "thing" to tweak the buoy with something different each
year. I go kayaking at 3:30 AM to avoid the summer heat, but it's a
challenge to find ways to see where I'm going in the dark on a lake
that's 2 miles long.

Radio beacon? or perhaps a super strobe that I can trigger from 2
miles away?

Tritium light?

Strontium aluminate paint?

Both would be fairly short range visibility. For longer range, why not
use GPS?

Tried that too. Got a Magellan "waterproof" little hand-held thingee.
Cost a small fortune and wasn't waterproof enough to take dunking in
water. Since they stopped the extended warranty plan, I stopped
taking it kayaking. It was hard to read too...

The nice thing about it was when I was on a new creek, I could see my
progress.

There are some cool cmos-sensor night vision cams around these days,
not expensive. We use one to film wildlife in the back yard at night,
skunks and cats and raccoons and things. But they are not as sensitive
as a real microchannel multiplier, and mostly not waterpoof.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[default]

On Fri, 19 May 2017 10:03:02 -0700, John Larkin
<jjlarkin@highlandtechnology.com> wrote:

On Fri, 19 May 2017 06:55:25 -0400, default <default@defaulter.net
wrote:

On Thu, 18 May 2017 08:43:17 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Thu, 18 May 2017 07:41:04 -0400, default <default@defaulter.net
wrote:

On 18 May 2017 06:00:58 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2017-05-13, default <default@defaulter.net> wrote:
On Sat, 13 May 2017 08:35:23 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Fri, 12 May 2017 06:47:01 -0400, default <default@defaulter.net
wrote:

On Fri, 12 May 2017 10:47:54 +0200, o pere o <me@somewhere.net> wrote:

On 11/05/17 00:42, Phil Hobbs wrote:
On 05/10/2017 02:31 PM, John Larkin wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

A conventional cap, no. Maybe a super expensive supercap.

I wouldn't want an electronic trash can. All that cheap, badly
programmed microprocessor/LCD appliance junk will break in a couple of
years, and be annoying meanwhile.

*SIX* AA cells? How long do they last?



A couple of supercaps in series might work fine. For instance,
SCMT22C505MRBA0 AVX CAPACITOR 5F 20% 5V 0.065ohms $5.23000 in onesies
from Digikey.

Two of those in series, with a TL431 across each one (set for 4.8V or
so) to equalize the voltage, plus a charger with about a 50 mA current
limit ought to work, I should think.

Cheers

Phil Hobbs


Is there data on leakage or self-discharge of these beasts? The
datasheet just says "low leakage current" and this could just mean
anything...

Pere

The caps I'm using give the leakage at .16 ma.

http://www.illinoiscapacitor.com/ic_search/super_products_detail.aspx?icpartnumber=700020


50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

more like 3 decimal places, 0.5*C*V*V/3600

I agree. Did the math and posted as much on 5/14.

I'm thinking they mistakenly used some "one size fits all" or
watt-hours per X farads.

In a related experiment... I'm temporarily using some Maxwell "D-cell"
series caps to power the buoy flasher that got 6 months of use from
3-AA alkaline cells, switching to a solar charged, 175 F, 3 V system
(using caps that cost $15 each). That system is flashing the strobe,
for 8 days on the charge it can get in one day. (cover the solar
cells with aluminum foil and wait till it dies).

So a pair of the $1.29 50 F caps should easily last a day, or perhaps
just use one 50 F and go with 2.5V. (specs on the controller that I'm
using says it works down to 2.2V, and it seems to recover and start
running it's program from the beginning when the voltage gets to about
2V)

The buoy that I'm illuminating belongs to the city.. So I have to keep
the cost low in case they discover that I've modified the buoy and
decide to remove my strobe, or vandals (or Visigoths) make it to that
end of the lake and steal or destroy it...

It's become a "thing" to tweak the buoy with something different each
year. I go kayaking at 3:30 AM to avoid the summer heat, but it's a
challenge to find ways to see where I'm going in the dark on a lake
that's 2 miles long.

Radio beacon? or perhaps a super strobe that I can trigger from 2
miles away?

Tritium light?

Strontium aluminate paint?

Both would be fairly short range visibility. For longer range, why not
use GPS?

Tried that too. Got a Magellan "waterproof" little hand-held thingee.
Cost a small fortune and wasn't waterproof enough to take dunking in
water. Since they stopped the extended warranty plan, I stopped
taking it kayaking. It was hard to read too...

The nice thing about it was when I was on a new creek, I could see my
progress.

There are some cool cmos-sensor night vision cams around these days,
not expensive. We use one to film wildlife in the back yard at night,
skunks and cats and raccoons and things. But they are not as sensitive
as a real microchannel multiplier, and mostly not waterpoof.

I'd love to have a small light waterproof camera to attach to my kite
when kite-yaking. Daylight is good enough for that, I only used the
kite twice in the dark and hundreds of times in daylight. Small and
lightweight are easy enough but waterproof is a whole 'nother thing.

 

[default]

On Fri, 19 May 2017 12:08:46 -0400, rickman <gnuarm@gmail.com> wrote:

On 5/19/2017 6:55 AM, default wrote:
On Thu, 18 May 2017 08:43:17 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Thu, 18 May 2017 07:41:04 -0400, default <default@defaulter.net
wrote:

On 18 May 2017 06:00:58 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2017-05-13, default <default@defaulter.net> wrote:
On Sat, 13 May 2017 08:35:23 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Fri, 12 May 2017 06:47:01 -0400, default <default@defaulter.net
wrote:

On Fri, 12 May 2017 10:47:54 +0200, o pere o <me@somewhere.net> wrote:

On 11/05/17 00:42, Phil Hobbs wrote:
On 05/10/2017 02:31 PM, John Larkin wrote:
On Wed, 10 May 2017 09:57:21 -0700, etpm@whidbey.com wrote:

I have an automatic opening trash can in the kitchen that runs off of
batteries. I wanna run it with a wall wart. When the lid opens it
draws more power than the 750 mA wall wart I tried using to power it
could deliver. This makes sense. I don't want to use a bigger wall
wart and I don't want to have betteries in it all the time to provide
the current. I'm thinking instead of using a capacitor. If the current
and voltage draw as well as the duration to open the lid is measured
can that not be used to calculate the minimum size capacitor? And if
not excessive maybe a cap that would open the lid three or four times
in a row could be used in place of the 6 AA cells it uses now.
Reasonable?
Thanks,
Eric

A conventional cap, no. Maybe a super expensive supercap.

I wouldn't want an electronic trash can. All that cheap, badly
programmed microprocessor/LCD appliance junk will break in a couple of
years, and be annoying meanwhile.

*SIX* AA cells? How long do they last?



A couple of supercaps in series might work fine. For instance,
SCMT22C505MRBA0 AVX CAPACITOR 5F 20% 5V 0.065ohms $5.23000 in onesies
from Digikey.

Two of those in series, with a TL431 across each one (set for 4.8V or
so) to equalize the voltage, plus a charger with about a 50 mA current
limit ought to work, I should think.

Cheers

Phil Hobbs


Is there data on leakage or self-discharge of these beasts? The
datasheet just says "low leakage current" and this could just mean
anything...

Pere

The caps I'm using give the leakage at .16 ma.

http://www.illinoiscapacitor.com/ic_search/super_products_detail.aspx?icpartnumber=700020


50.625 watt hours???!!!

It's magic, or a decimal point slipped 2 places. 1/2 watt I might
believe.

more like 3 decimal places, 0.5*C*V*V/3600

I agree. Did the math and posted as much on 5/14.

I'm thinking they mistakenly used some "one size fits all" or
watt-hours per X farads.

In a related experiment... I'm temporarily using some Maxwell "D-cell"
series caps to power the buoy flasher that got 6 months of use from
3-AA alkaline cells, switching to a solar charged, 175 F, 3 V system
(using caps that cost $15 each). That system is flashing the strobe,
for 8 days on the charge it can get in one day. (cover the solar
cells with aluminum foil and wait till it dies).

So a pair of the $1.29 50 F caps should easily last a day, or perhaps
just use one 50 F and go with 2.5V. (specs on the controller that I'm
using says it works down to 2.2V, and it seems to recover and start
running it's program from the beginning when the voltage gets to about
2V)

The buoy that I'm illuminating belongs to the city.. So I have to keep
the cost low in case they discover that I've modified the buoy and
decide to remove my strobe, or vandals (or Visigoths) make it to that
end of the lake and steal or destroy it...

It's become a "thing" to tweak the buoy with something different each
year. I go kayaking at 3:30 AM to avoid the summer heat, but it's a
challenge to find ways to see where I'm going in the dark on a lake
that's 2 miles long.

Radio beacon? or perhaps a super strobe that I can trigger from 2
miles away?

Tritium light?

Strontium aluminate paint?

Both would be fairly short range visibility. For longer range, why not
use GPS?

Tried that too. Got a Magellan "waterproof" little hand-held thingee.
Cost a small fortune and wasn't waterproof enough to take dunking in
water. Since they stopped the extended warranty plan, I stopped
taking it kayaking. It was hard to read too...

The nice thing about it was when I was on a new creek, I could see my
progress.

They are rated as waterproof, but not very waterproof. I've yet to find
one that will survive on the deck of a kayak for more than a season.
Sooner or later they leak and crap out.

I've never had any trouble seeing where I'm going. Even starlight is
enough to navigate. Once the stars are gone you have to know your
terrain (aquaine?) pretty well though. Overcast makes for interesting
trips though. I take you paddle where there is no illumination from
houses and such? Even a single porch light in the distance can provide
orientation.

Most days (nearly every day) I paddle to the end of the lake and turn
around and come back. There are two large bays jutting off the main
lake and one is nearly as long as the main lake. Add a little fog
(there have been times where I had no idea where I was) and navigation
gets interesting. The houses at the end of the lake make spotting the
buoy difficult for their lights and glare.

It's nice to be able to make a beeline for the buoy, then I'm sure I
cover the same amount of ground each time, and can time my runs.

It isn't a matter of life or death, or even important that I see the
buoy. But I got interested in how to best find it in the dark, and
that's evolved into a fun excuse to tinker with electronics.

Then there's the alligators... It's a big lake and there can only be
4-5 gators in it, but on three occasions I managed to surprise
sleeping gators - against all odds I would think. There's nothing
quite like paddling into a sleeping gator to get one's adrenaline up.
And I may know I'm not part of his food chain, but does he know? And
those things are so near-sighted they just might take me for another
gator impinging on his territory or mate.