Chip with simple program for Toy

[Angelo Campanella]

WayneL wrote:

Can anyone advise where I can get Quartz triple distilled water from (I'm in
the UK) and what is it the best conductivity you could expect from the most
purest water

The purer, the higher the resistance.
See other messages here (18 megohm-cm, etc.)

Also what is the best way of 1/ storing ultra pure water and 2/ dispensing
it so that the rest of the water does not get contaminated. Should I
dispense it in to several small bottles with pipette lids?

Bottle material is important.
Can't say which is the best; it's not obvious.

Angelo Campanella

 

[W. Watson]

Sylvan Butler wrote:

On Fri, 31 Dec 2004 06:00:23 GMT, W. Watson <wolf_tracks@invalid.inv> wrote:

I decided to buy a 60 minute timer at the local h/w store and a two outlet socket. I


That's what I did.


figured I could put this in an electrical connection square metal box with a 3-prong


The metal box should work fine. (Don't forget to ground it.) Only
caveat, is that normally the devices mount to the cover instead of the
box, or else to a secondary ring (box, ring+devices, cover).

I just put them into a plastic electrical box, put a plastic cover plate
over them. No problem. Even a shallow box is deep enough. Did you
just not want to use plastic?

Oh, and I'm considering splitting the outlet such that 1/2 is always on,
the other half runs from the timer.

sdb
Breaking your e-mail address was interesting. Heavens! I wonder this msg will get to

you via my attempt.

It's good to know that you had the determination to see this through. I had some
thought of just buying a standard metal box, and slipping it all in. When I got into
it, I found the 2 prong outlet fixture wouldn't stretch across the box, and I
couldn't get a face plate to put across the outlet side. The 60 min timer didn't
quite fit either. I must have spent 90 minutes traveling among h/w and electric
stores looking for readily available parts to just sort of screw it all together
without using a hacksaw, drills, etc. This was turning into a bigger project that I
needed. I finally took it all back, but may try again another day.

I would think the fact that I have 3-prong outlets everywhere, and the use of a
3-prong plug for this apparatus, would be sufficient to ground it? I would have
thought something like this would have some consumer demand, but I guess not. It's
strictly a do-it-yourself deal. There may be some that cost $100+. Very odd.

--
Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA)
(121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
Obz Site: 39° 15' 7" N, 121° 2' 32" W, 2700 feet

Web Page: <home.earthlink.net/~mtnviews>

 

[Sylvan Butler]

On Sun, 09 Jan 2005 06:09:28 GMT, W. Watson <wolf_tracks@invalid.inv> wrote:

Sylvan Butler wrote:
I just put them into a plastic electrical box, put a plastic cover plate
over them. No problem. Even a shallow box is deep enough. Did you

Breaking your e-mail address was interesting. Heavens! I wonder this msg will get to

Sorry. The second line of my sig should work:
sdbuse1 on mailhost bigfoot.com
(given that "on mailhost" in e-mail syntax is an "@" symbol)

needed. I finally took it all back, but may try again another day.

If you're ever in the area of Boise, Idaho, I'd be willing to meet at
the hardware store to help you get the needed bits. And the folks at
Grover's PayNPak are usually very helpful as well.

sdb
--
Wanted: Omnibook 800 & accessories, cheap, working or not
sdbuse1 on mailhost bigfoot.com

 

[Bob Masta]

On Sat, 08 Jan 2005 15:16:08 GMT, "Matt J. McCullar"
<mccullar@flash.net> wrote:
<snip>

I remember when I was a kid, picking up WBAP-820 AM radio very clearly over
my little 3" reel-to-reel tape recorder speaker whenever I touched my finger
to the terminals of the playback head. I guess my body was acting like a
capacitor/antenna. WBAP is a big powerhouse and at the time I lived in the
same city (Fort Worth).

The fact that the body is a good antenna for AM is one of the things
that makes me think the mouth would make a good Faraday cage.
It must be a pretty good conductor at those wavelengths. But
I'd sure like to be able to put some numbers on it. How does one
determine the degree of Faraday screening, given the conductance
(or whatever) of the screening material?

Thanks!


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

 

[CWatters]

<geekscosmos@yahoo.com> wrote in message
news:1105356530.773713.244670@c13g2000cwb.googlegroups.com...

I have a gas cylinder - H Tank (that can hold oxygen, helium, etc... at
50 psi pressure) that is used for clinical simulation. It has its own
valve that can be switched on / off manually.

Perhaps they a company like this...
They have equipment for mixing/controlling gasses...
http://www.acmecryo.com/main/cms_products.asp

 

[John Popelish]

Dominic-Luc Webb wrote:

On Sat, 8 Jan 2005, John Popelish wrote:

Dominic-Luc Webb wrote:

It is also frustrating that the specifications often do not tell what
kind of NPN transistor. I have seen the 2N3055 called a Darlington,
and I have seen internal schematics that clearly show that it is not.

It is always a good idea to review the data sheet if you can find one:
http://www.onsemi.com/pub/Collateral/2N3055-D.PDF

--
John Popelish

I have several. I do not necessarily trust these. Note that some of them
currently available on the Net (I just found one) specified Vce in units
of amperes, for instance. In some cases, the units are mixed up. Thanks
for the link, John. I do not have this particular one, and scanning
through it, I do not see this error. Indeed, there appear to be some
numbers I have not seen. On the other hand, note that it is not clearly
stated that it is even an NPN at all. This appears further down, in the
sheet, but it is almost inadvertant. Further, this spec sheet does not
show any internal archecture and does not seem to state whether or not
this is a single NPN or Darlington config. In the case of the 2N3055,
there are so many newby's, this little bit of extra blurb would be
useful to quite a few customers.

The data sheet says on the first page that these are power
transistors, not power darlingtons. Every figure on page 3 labels the
2N3055 as NPN. Since this is a combined data sheet for a
complementary pair, one of then has to be a PNP and one has to be an
NPN.

Perhaps you like the initial description on this one, better.
http://rocky.digikey.com/WebLib/ST%20Micro/Web%20Data/2N3055,%20MJ2955.pdf

So what do you make of the problem of getting the 2N3055 to shut off?
Could it be damaged?

That is always a possibility ot be checked out. But I don't have
enough details on the application to say. Care to tell me the
details, again, of the circuit that gave you trouble?

--
John Popelish

 

[Danny T]

Dominic-Luc Webb wrote:

One thing that does not make sense is that Danny gets a varying low. I
would think low should be right at ground potential for this circuit.

It was bad code - it was only on part of the time, and my meter was
averaging the high/lows!

--
Danny

 

[JeffM]

gas cylinder...can hold oxygen, helium, etc....
used for clinical simulation...
automate this valve...to control the flow of gas
geekscosmos

The *clinical* part bothers me.
Do you mean that you will be using it on humans?
I suggest hiring a Biomedical Engineer.

I have a story about a young, eager physician
doing a pulmonary experiment using a helium mixture
on a Saturday with no one else around.
He survived, but it could have gone very badly.

A little light reading about Pneumatic Solenoid Valves:
http://www.google.com/search?&q=pneumatic+solenoids+asco+brands


I also suggest
that you remove the @Yahoo.com from your user name.
The Google arcive now mungs all email addresses
(especially when you post there)
so that they look like this: geekscos...@yahoo.com.
(I had to make an effort to un-mung it.)

 

[Bob Masta]

On 10 Jan 2005 10:41:20 -0800, "JeffM" <jeffm_@email.com> wrote:

gas cylinder...can hold oxygen, helium, etc....
used for clinical simulation...
automate this valve...to control the flow of gas
geekscosmos

The *clinical* part bothers me.
Do you mean that you will be using it on humans?
I suggest hiring a Biomedical Engineer.

I have a story about a young, eager physician
doing a pulmonary experiment using a helium mixture
on a Saturday with no one else around.
He survived, but it could have gone very badly.

I also have a story like that, only my boss wanted to
use hydrogen and oxygen premixed in a stochiometric mixture.
(This was for auditory research on Guinea pigs.)
Luckily for us all, he wasn't able to find a supplier and
asked me to help. It took some doing, but I finally
convinced him that this was a REALLY bad idea, even
if he found some fool to mix it for him. From what
I was able to find out at the time, there were no valves
available that could respond fast enough to prevent a flame
front from travelling back into the tank and turning
it into a scale model Saturn V rocket.




Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

 

[SioL]

"Bob Masta" <NoSpam@daqarta.com> wrote in message news:41e2854d.2219475@news.itd.umich.edu...

On Sat, 08 Jan 2005 15:16:08 GMT, "Matt J. McCullar"
mccullar@flash.net> wrote:
snip
I remember when I was a kid, picking up WBAP-820 AM radio very clearly over
my little 3" reel-to-reel tape recorder speaker whenever I touched my finger
to the terminals of the playback head. I guess my body was acting like a
capacitor/antenna. WBAP is a big powerhouse and at the time I lived in the
same city (Fort Worth).


The fact that the body is a good antenna for AM is one of the things
that makes me think the mouth would make a good Faraday cage.
It must be a pretty good conductor at those wavelengths. But
I'd sure like to be able to put some numbers on it. How does one
determine the degree of Faraday screening, given the conductance
(or whatever) of the screening material?

How about stuffing AM radio up your arse and checking whether
you can still hear the audio from the radio station?

Or doing the same with your mouth.

Just an idea

SioL

 

[Danny T]

Bob Masta wrote:

But the real show-stopper, I think, would be the fact that
the whole "radio" is inside the mouth, surrounded by
conductive tissue with no antenna protruding... a pretty
good Faraday cage, I reckon. (Or maybe the radio
only works when you stick out your toungue...!)

And it just so happens that your teeth are "tuned" perfectly to a local
station?

--
Danny

 

[Danny T]

Danny T wrote:
<snip>

Would one of these per motor do?

http://www.rapidelectronics.co.uk/rkmain.asp?PAGEID=80010&CTL_CAT_CODE=&STK_PROD_CODE=M60258&XPAGENO=1

Any advantages to either way (using these, or doing something similar to
my first post)?

--
Danny

 

[Andrew Holme]

Danny T wrote:

I've got little motors that change direction if you reverse the
polarity. What's the best way to achieve this from a PIC? I was
thinking
something like this:


VCC
+
| .------------------------------.
| | |
'--)----------o--------. |
| | | |
| | V Diode |
| | - |
| | '-----. |
| | | | | __
| | _-_ | | -o|P |o-
| |Motor |___| | | -o|I |o-
| | - | '---o|C |o-
| .----)--------' | .---o|__|o-
| | | | | |
| | | - | |
| | | Diode ^ | |
| |D | | D| |
| ||-+ '--------' +-||-
|G ||<- ->|| G
'--||-+ +-||
| S S |
---------------------------'
|
===
GND



GND
(created by AACircuit v1.28.4 beta 13/12/04 www.tech-chat.de)

However I'm not sure about the diodes, and power heading for the
chip,
instead of the motor. What's the usual way to do this kind of thing?

Thanks,
--
Danny

No, that won't work. The power supply would short-circuit through a
diode and a MOSFET. You have to use the H-bridge configuration:
http://www.google.co.uk/search?q=motor+mosfet+%22h-bridge%22

 

[Andrew Holme]

Danny T wrote:

Danny T wrote:
snip

Would one of these per motor do?


http://www.rapidelectronics.co.uk/rkmain.asp?PAGEID=80010&CTL_CAT_CODE=&STK_PROD_CODE=M60258&XPAGENO=1

Any advantages to either way (using these, or doing something similar
to my first post)?

Yes, you could do it with a relay. You need a back e.m.f. protection diode
across the relay coil and a MOSFET to drive it from the PIC. An
all-semiconductor solution might be more elegant (H-bridge) but a relay is
simpler.

 

[Danny T]

Andrew Holme wrote:

No, that won't work. The power supply would short-circuit through a
diode and a MOSFET. You have to use the H-bridge configuration:
http://www.google.co.uk/search?q=motor+mosfet+%22h-bridge%22

Thanks Andy. Found this:

http://www.dprg.org/tutorials/1998-04a/hb6.png

So do I just need some PNP mosfets the same as the NPN ones I already
have? Is it possibly to drive two MOSFETs (the PNP from one side, and
NPN from the other) from the same IC pin?

Ta,
--
Danny

 

[Danny T]

Andrew Holme wrote:

Would one of these per motor do?

http://www.rapidelectronics.co.uk/rkmain.asp?PAGEID=80010&CTL_CAT_CODE=&STK_PROD_CODE=M60258&XPAGENO=1

Any advantages to either way (using these, or doing something similar
to my first post)?

Yes, you could do it with a relay. You need a back e.m.f. protection diode
across the relay coil and a MOSFET to drive it from the PIC. An
all-semiconductor solution might be more elegant (H-bridge) but a relay is
simpler.

I've just been looking on rapid (www.rapidelec.co.uk) where I got my
N-channel MOSFETs, but they don't seem to have any similar P-Channel
ones. None rated at 1A of the same product, and some of the other
products are 80-100V, and/or don't say if they're NPN or PNP :-(

--
Danny

 

[Anthony Fremont]

"Danny T" <danny@nospam.oops> wrote in message
news:41e51060$0$96019$ed2619ec@ptn-nntp-reader02.plus.net...

Danny T wrote:
snip

Would one of these per motor do?


http://www.rapidelectronics.co.uk/rkmain.asp?PAGEID=80010&CTL_CAT_CODE=&STK_PROD_CODE=M60258&XPAGENO=1

Any advantages to either way (using these, or doing something similar
to
my first post)?

Your first schematic shorts the power supply to ground when you turn on
one of the mosfets.

What you really want is an H-Bridge. You can use one of the available
h-bridge integrated circuits, but you may wish to build your own out of
discrete components.

You can use the mosfets you've already obtained for the low side
switching, but you will need something different for the high side
switch. You could use some standard p-channel mosfets, but switching
them on can be a pain. I really like these things, they are quite neat:
http://www.rapidelectronics.co.uk/rkmain.asp?PAGEID=80010&CTL_CAT_CODE=30412&STK_PROD_CODE=M34955&XPAGENO=1
They are often called smart power switches because they contain more
than just a p-channel mosfet, they are usually short-circuit protected
and have the ability to tell you if the circuit is open. They also
contain all the necessary circuitry to take a logic level input and
apply the appropriate gate drive to the internal transistor. I think
they were primarily developed for the automotive industry, but would
work well in your application.

 

[Anthony Fremont]

"Danny T" <danny@nospam.oops> wrote in message
news:41e5053b$0$14591$ed2619ec@ptn-nntp-reader01.plus.net...

Bob Masta wrote:

But the real show-stopper, I think, would be the fact that
the whole "radio" is inside the mouth, surrounded by
conductive tissue with no antenna protruding... a pretty
good Faraday cage, I reckon. (Or maybe the radio
only works when you stick out your toungue...!)

And it just so happens that your teeth are "tuned" perfectly to a
local
station?

Well that's the really neat thing about AM demodulation, you don't have
to have anything tuned. You only need a simple rectifier.

 

[Danny T]

Anthony Fremont wrote:

You can use the mosfets you've already obtained for the low side
switching, but you will need something different for the high side
switch. You could use some standard p-channel mosfets, but switching
them on can be a pain. I really like these things, they are quite neat:
http://www.rapidelectronics.co.uk/rkmain.asp?PAGEID=80010&CTL_CAT_CODE=30412&STK_PROD_CODE=M34955&XPAGENO=1
They are often called smart power switches because they contain more
than just a p-channel mosfet, they are usually short-circuit protected
and have the ability to tell you if the circuit is open. They also
contain all the necessary circuitry to take a logic level input and
apply the appropriate gate drive to the internal transistor. I think
they were primarily developed for the automotive industry, but would
work well in your application.

That all sounds fantastic, but while I'm testing and potentially
destroying things, they're probably a bit OTT (and expensive),
especially in comparison to the low-side ones I've got! (about 50p each!)

--
Danny

 

[Dominic-Luc Webb]

2N3055 does this:

16.2 ___ ___ ___
| | | | | |
16V --- ---- ---- ---

Never drops to ground potential. It can in some cases go to roughly
12 times high frequency, as well.

Dominic

I can't think that your 2N3055 is good, unless you have reversed the
base and emitter pins or something similar. It has a lot more charge
storage than the smaller transistor, so it is harder to turn it on and
off quickly, but at this frequency, that should behave very similarly,
except for leakage and rise and fall time. What you describe is not
explained by the difference in the two types.

--
John Popelish

Thanks John!

I suspect it is bad, and I'll plan to try a new one. I do not think the
spec sheets, combined with the info I got with the transistor when I
bought it are very ambiguous, so wiring is certainly correct. The overall
circuit is correct since it works with all other transistors, taking into
account Ic and Ib, etc for each transistor.

Regarding the spec sheet you mentioned:
http://rocky.digikey.com/WebLib/ST%20Micro/Web%20Data/2N3055,%20MJ2955.pdf

I could not help noticing that here too, DC Current gain (hFE* in
Electrical Characteristics section) is specified as Vce = 4 Amps. Is
it is ever correct to state Vce in amps or typo? This is confusing.

For the next level of complexity, I believe that the low beta of the
2N3055 means it has a narrow dynamic range (varying Ic with fixed base
voltage and resistor) in which it will operate normally. If I understand
these transistor specs and math correctly, I believe this also means that if
I have a varying load, as would be the case with a photomultiplier tube
pulling current from a transformer driven via this transistor, then a much
larger beta could be desirable (i.e., more dynamic range). I think a PMT can
draw anything from 1 nA to 1 mA. The counts per second in pulse counting
mode can go from a few hundred to 10's of millions.

Dominic