Chip with simple program for Toy

[Ruediger]

loedown wrote:

These sort of applications are ideal for PIC chips, simple to use, require
almost no auxilliary circuitry, and are easy to program. Very steep
learning
curve, and the programmer will set you back somewhere in the order of
$200 AUD, but the PIC 18F672 has provision for RS232 and multiple outputs
(22).

Paul

Even better: Most PIC's can be programmed over their In-System-Programming
ports, and all it needs is a simple circuit; the manufacturer,
http://www.microchip.com
has the DIY-programmer somewhere in their application-sheets.

The ideal multipurpose workhorse that I fell in love with is the PIC16F88, a
little beast we are now using in a wearable device we develop at the
University. My greates flaw is, I'm lousy at rogrmming, my skill is
designig circuitry.

I have an idea for a very cheap, but highly versatile wearable device in my
head, but I would need to first develop the circuitry and look for the
parts and their costs ( it should be a device priced about 30$, requiring a
PeeCee somewhere, connecting to it by wireless. ). That baby would need
some good amount of programming, especially on the PC's side, where a lot
of outputs would need to be redirected, requiring, hum... sorta like a
X-driver for the parallel port

Anyway.

My PIC of choice for multipurpose -USage is the PIC 16F88. 2*8Bit-Ports, so
lotsa outputs.
--
Hochachtungsvoll

Rüdiger

 

[Chris W]

Ruediger wrote:

loedown wrote:



These sort of applications are ideal for PIC chips, simple to use, require
almost no auxilliary circuitry, and are easy to program. Very steep
learning
curve, and the programmer will set you back somewhere in the order of
$200 AUD, but the PIC 18F672 has provision for RS232 and multiple outputs
(22).

Paul



Even better: Most PIC's can be programmed over their In-System-Programming
ports, and all it needs is a simple circuit; the manufacturer,
http://www.microchip.com
has the DIY-programmer somewhere in their application-sheets.

The ideal multipurpose workhorse that I fell in love with is the PIC16F88, a
little beast we are now using in a wearable device we develop at the
University. My greates flaw is, I'm lousy at rogrmming, my skill is
designig circuitry.

I have an idea for a very cheap, but highly versatile wearable device in my
head, but I would need to first develop the circuitry and look for the
parts and their costs ( it should be a device priced about 30$, requiring a
PeeCee somewhere, connecting to it by wireless. ). That baby would need
some good amount of programming, especially on the PC's side, where a lot
of outputs would need to be redirected, requiring, hum... sorta like a
X-driver for the parallel port

Anyway.

My PIC of choice for multipurpose -USage is the PIC 16F88. 2*8Bit-Ports, so
lotsa outputs.


What about something like the RABBIT Microprocessor modules? Wouldn't

that be the easy way? Could I program something like that in C?

Also does someone make some kind of IC chip that takes say 3 bit binary
number for input on 3 pins and then makes one of 8 output pins go high
based on the input binary number?


--
Chris W

Gift Giving Made Easy
Get the gifts you want &
give the gifts they want
http://thewishzone.com

"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania

 

[John Fields]

On Tue, 15 Feb 2005 23:16:29 GMT, "Lord Garth" <LGarth@Tantalus.net>
wrote:

"Chris W" <1qazse4@cox.net> wrote in message
news:LxuQd.63925$jn.19302@lakeread06...
Ruediger wrote:

loedown wrote:
snip
Also does someone make some kind of IC chip that takes say 3 bit binary
number for input on 3 pins and then makes one of 8 output pins go high
based on the input binary number?


The 74HC138 is such a chip but the outputs go low based upon the input.
You can do this function with any EPROM if you wish.

---
I couldn't find loedown's post to reply to it specifically, but the
HC238 is an HC138 with positive true outputs.

--
John Fields

 

[Rich Grise]

On Tue, 15 Feb 2005 16:16:38 -0600, Chris W wrote:

Ruediger wrote:
loedown wrote:
[in response to an OP which he entirely snipped]
These sort of applications are ideal for PIC chips, simple to use,
require almost no auxilliary circuitry, and are easy to program. Very
steep learning
curve, and the programmer will set you back somewhere in the order of
$200 AUD, but the PIC 18F672 has provision for RS232 and multiple
outputs (22).

Even better: Most PIC's can be programmed over their
In-System-Programming ports, and all it needs is a simple circuit; the
manufacturer, http://www.microchip.com
has the DIY-programmer somewhere in their application-sheets.
....
Anyway.

My PIC of choice for multipurpose -USage is the PIC 16F88. 2*8Bit-Ports,
so lotsa outputs.


What about something like the RABBIT Microprocessor modules? Wouldn't
that be the easy way? Could I program something like that in C?

Also does someone make some kind of IC chip that takes say 3 bit binary
number for input on 3 pins and then makes one of 8 output pins go high
based on the input binary number?

Google is your friend:
http://www.google.com/search?q=digital+electronics+basics&btnG=Search

Have Fun!
Rich

 

[Chris W]

Lord Garth wrote:

"Chris W" <1qazse4@cox.net> wrote in message
news:LxuQd.63925$jn.19302@lakeread06...


Ruediger wrote:



loedown wrote:


snip


Also does someone make some kind of IC chip that takes say 3 bit binary
number for input on 3 pins and then makes one of 8 output pins go high
based on the input binary number?




The 74HC138 is such a chip but the outputs go low based upon the input.
You can do this function with any EPROM if you wish.





I also found the 238 version which is more what I want. Can you tell me

more about how I would use and EPROM to do that and is there a 4 to 16
line encoder too? I can't find one at Mouser.com

--
Chris W

Gift Giving Made Easy
Get the gifts you want &
give the gifts they want
http://thewishzone.com

"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania

 

[Lord Garth]

"Chris W" <1qazse4@cox.net> wrote in message
news:_EzQd.63948$jn.23253@lakeread06...

Lord Garth wrote:

Also does someone make some kind of IC chip that takes say 3 bit binary
number for input on 3 pins and then makes one of 8 output pins go high
based on the input binary number?




The 74HC138 is such a chip but the outputs go low based upon the input.
You can do this function with any EPROM if you wish.





I also found the 238 version which is more what I want. Can you tell me
more about how I would use and EPROM to do that and is there a 4 to 16
line encoder too? I can't find one at Mouser.com

Sure Chris,

Firstly, you need to call it a decoder. Either a 3 to 8 demultiplexer /
decoder or
a 4 to 16 demultiplexer. The old TTL part number for this was the 74154.

To use a EPROM for this function, you would program the output pattern to
whatever you need for a given input pattern. The inputs go to the address
lines,
A3 A2 A1 A0 for 4 bits and the unused address lines are grounded.
Don't forget to enable the EPROM with its *CS input and enable its outputs
with the *OE input. Many need the Vpp pin set high as well.

This is a great use for those old 2K EPROMs that often get tossed. Newer
EPROM
part numbers usually reflect the number of bits (not bytes) they can hold.
A 27128
holds 128k bits which is arranged as 16k x 8. Older EPROMs had part numbers
like 2716. The 2716 is 2k x 8. Address range from 0000 through 1FFF, most
of
which will be wasted in your application but its a wasted part by most
standards.

Note too that you can use two '238 to form a 16 line decoder by making use
of
the enable inputs. The A2 A1 A0 inputs go to both 238s while A3 goes to the
active high enable one 238 and the active low enable on the other.

Have fun and let us know if you need an EPROM programmed.

 

[Chris W]

Lord Garth wrote:

Sure Chris,

Firstly, you need to call it a decoder. Either a 3 to 8 demultiplexer /
decoder or
a 4 to 16 demultiplexer. The old TTL part number for this was the 74154.


I don't know where I encoder came from I meant to type decoder. the

search for demultiplexer found the 4 to 16 line version at mouser.com

To use a EPROM for this function, you would program the output pattern to
whatever you need for a given input pattern. The inputs go to the address
lines,
A3 A2 A1 A0 for 4 bits and the unused address lines are grounded.
Don't forget to enable the EPROM with its *CS input and enable its outputs
with the *OE input. Many need the Vpp pin set high as well.

Let me see if I get the idea. It sounds like the EPROMs mostly have an
8 bit output. So for the case of turning on 1 of 8 lights, I basically
program in 8, 8 bit numbers so I would use 8 bytes or 64 bits of memory
from the EPROM. Are EPROMs that have 16 bit output very expensive? Or
would I be better off using 2 with 8 bit outputs? The EPROM way sounds
like an interesting solution. I want to have the possibility of having
as many as 16 separate boards that each control 16 lights. So I could
program the EPROM(S) on each board to respond to 8 bit binary inputs
like so..

Board 1 responds to 0 to 15
Board 2 responds to 16 to 31
Board 3 responds to 32 to 47
.. . .
Board 16 responds to 240 to 255

I like that!

Now for a few questions. Would an 8 bit output from a PIC have a
problem driving as many as 16 of these circuits hooked in parallel? My
first application is going to drive a single high intensity white LED on
each of the possible 256 output lines. I believe they draw around 20mA
at about 3.5V, will I need some kind of driver or will the circuit
handle enough power to drive all 16 lights on each board at a time?
Finally how to turn on or off each LED, and leave them in that state
till the next signal. Would a flip flop would be the way to go? Some
way to tell it to turn off or on might be nice, that way I wouldn't have
to keep as close a track to which lights were on and which were off.

--
Chris W

Gift Giving Made Easy
Get the gifts you want &
give the gifts they want
http://thewishzone.com

"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania

 

[Fred Bloggs]

First, Polar makes a small stand-alone receiver unit for their
transmitters. The transmitters output a "burst" at 5KHz for each qrs
detected. At this frequency, you don't use a conventional antenna, but
rather a resonance-tuned coupling coil. The range is *very* limited (less
than 2 meters) and is prone to interference.

The range is only slightly more than arms length because it is designed
to be used in a group setting where several people can use them without
interference- and this works *well*. The receiver is locking to a
transmitter rate in addition to just simple detection so there is
selectivity not only on signal frequency but also by steady heart rate.
The transmitter requires a moisture layer between the skin and strap for
best sensitivity- so if you're just sitting there in your Lazy-Boy
versus getting off your ass and sweating, then the Polar is not for you.

 

[Lord Garth]

"Chris W" <1qazse4@cox.net> wrote in message
news:jcEQd.63960$jn.8959@lakeread06...

Lord Garth wrote:

Sure Chris,

Firstly, you need to call it a decoder. Either a 3 to 8 demultiplexer /
decoder or
a 4 to 16 demultiplexer. The old TTL part number for this was the 74154.


I don't know where I encoder came from I meant to type decoder. the
search for demultiplexer found the 4 to 16 line version at mouser.com

To use a EPROM for this function, you would program the output pattern to
whatever you need for a given input pattern. The inputs go to the
address
lines,
A3 A2 A1 A0 for 4 bits and the unused address lines are grounded.
Don't forget to enable the EPROM with its *CS input and enable its
outputs
with the *OE input. Many need the Vpp pin set high as well.




Let me see if I get the idea. It sounds like the EPROMs mostly have an
8 bit output. So for the case of turning on 1 of 8 lights, I basically
program in 8, 8 bit numbers so I would use 8 bytes or 64 bits of memory
from the EPROM. Are EPROMs that have 16 bit output very expensive? Or
would I be better off using 2 with 8 bit outputs? The EPROM way sounds
like an interesting solution. I want to have the possibility of having
as many as 16 separate boards that each control 16 lights. So I could
program the EPROM(S) on each board to respond to 8 bit binary inputs
like so..

Board 1 responds to 0 to 15
Board 2 responds to 16 to 31
Board 3 responds to 32 to 47
. . .
Board 16 responds to 240 to 255

I like that!

Now for a few questions. Would an 8 bit output from a PIC have a
problem driving as many as 16 of these circuits hooked in parallel? My
first application is going to drive a single high intensity white LED on
each of the possible 256 output lines. I believe they draw around 20mA
at about 3.5V, will I need some kind of driver or will the circuit
handle enough power to drive all 16 lights on each board at a time?
Finally how to turn on or off each LED, and leave them in that state
till the next signal. Would a flip flop would be the way to go? Some
way to tell it to turn off or on might be nice, that way I wouldn't have
to keep as close a track to which lights were on and which were off.

--
Chris W

I would never allow the PIC to drive the lamps directly, I'd buffer the
outputs
in one of several ways.

The EPROM is always used in a minimum of a byte so excepting for the part
number, there is no need to concern yourself about the number of bits you
have
used. 16 bit EPROMs are more expensive and few cheap programmers can use
handle them, better to use two 8 bit device and some very easy control logic
as described for dual 238s. You can also look into multiplexing the outputs
to accomplish your goal.

Maxim has an IC that, in one mode of operation, can address as many as 64
separate lamps. I do not recall its part number but this chip might well be
worth your time to investigate.

I need to run, I have work to do.....

 

[Lord Garth]

"Fred Abse" <excretatauris@cerebrumconfus.it> wrote in message
newsan.2005.02.16.21.03.19.860325@cerebrumconfus.it...

On Sun, 13 Feb 2005 20:27:29 +0000, John Woodgate wrote:

Yes, prone to 'autonomous energetic disassembly'. (;-)

I once made some copper acetylide at school.

Nitrogen triiodide was good, too...

Amazing what you could get away with back then.

--
Then there's duct tape ...
(Garrison Keillor)

Hmm, I used to make ammonium tri-iodide in HS...
It worked well on the erasers with the expected pops,
but be careful.

 

[Lord Garth]

"Chris W" <1qazse4@cox.net> wrote in message
news:2OOQd.63983$jn.59042@lakeread06...

I want a circuit that will turn a light on with the press of a momentary
switch and then turn it back off when the momentary switch is hit
again. I had heard that a flip flop might be the way to go. After some
reading, I have found that a flip flop is a much more complex device
than I was lead to believe. I think a flip flop would some how do the
job, but it is going to take some more reading before I figure out how.
If you have been reading some of my other posts, you know that I want to
turn on and off more than one light, so I need several of these
circuits, preferably using the minimum number of components.

Another option I would like to explore is to turn the light on and off
using 2 inputs. Say we have in put A and B. If input B is high, when
input A goes high, turn the light on, or leave it on. If input B is
low, when input A goes hight, turn the light off, or leave it off.

Don't let a little flip-flop stop you. You should research the T flip-flop
and a debounce circuit for your clock input. That's the button that makes
it do it thing Chris, not a time of day clock!

 

[Thot]

Hello,
I am very interest myslef in being able to log and analyze in a computer
overnight heart rates with the Poalr chest band or other systems.

can you post more details?

Thanks

Luca



"Dan Major" <nospam@this.address> wrote in message
news:Xns95FEC23895A26soonerboomergbronlin@68.12.19.6...

Mark Witczak <witczak@acm.org> wrote in news:nCwQd.36312$Vg3.2296
@lakeread05:

Hi,

Does anyone have or is familiar with designing/building a receiver for
the Polar Heart Rate Monitor transmitter?

Thanks,
Mark


First, Polar makes a small stand-alone receiver unit for their
transmitters. The transmitters output a "burst" at 5KHz for each qrs
detected. At this frequency, you don't use a conventional antenna, but
rather a resonance-tuned coupling coil. The range is *very* limited (less
than 2 meters) and is prone to interference. I gave up on the Polar stuff
and made my own system using off-the-shelf RF modules at 413MHz.

 

[Adrian Godwin]

Thot <brigatti@cox.net> wrote:

Hello,
I am very interest myslef in being able to log and analyze in a computer
overnight heart rates with the Poalr chest band or other systems.

can you post more details?

I've been thinking of something similar and bought a cheap (Aldi)
HRM to experiment with. This uses a similar method to the (uncoded)
Polar units, in this case a 5.3kHz burst. Seems to be close enough
to work with standard gym machines.

If you google back through the sci.electronics newsgroups you'll
find a few comments about the Polar units - the reciever apparently
uses a Neosid encapsulated inductor as the receive coil.

Given the audio frequency, it seems to me that a very cheap logger
could be built by constructing a circuit built around an open-cored
inductor and tuned to about 5kHz. Such a circuit will show 5kHz
pulses even on an insensitive scope if held close to the HRM band.
Add, perhaps, a little more filtering and a microphone preamp and
then send the resulting signal to an audio recorder - one of the
tiny flash-based music players with a microphone socket would be
convenient, but experiments could be done with a PC sound card.

Finally, extract the 5kHz pulses from the recorded data file
using software on the PC. I don't know what effect compression
will have on the recording, but it would be easy to generate
a test file without building any hardware at all.

-adrian

 

[Bob Masta]

On Wed, 16 Feb 2005 21:17:51 GMT, "Lord Garth" <LGarth@Tantalus.net>
wrote:

"Fred Abse" <excretatauris@cerebrumconfus.it> wrote in message
newsan.2005.02.16.21.03.19.860325@cerebrumconfus.it...
On Sun, 13 Feb 2005 20:27:29 +0000, John Woodgate wrote:

Yes, prone to 'autonomous energetic disassembly'. (;-)

I once made some copper acetylide at school.

Nitrogen triiodide was good, too...

Amazing what you could get away with back then.

--
Then there's duct tape ...
(Garrison Keillor)


Hmm, I used to make ammonium tri-iodide in HS...
It worked well on the erasers with the expected pops,
but be careful.

Indeed. On the last day of the semester in HS chemistry,
the instructor allowed my buddy and me to make some
after class. We were having a hard time getting the
precipitate to pass through the filter paper, so we hit
on the bright idea that maybe a little added water
would help wash out the clogs. Only trouble was that
we weren't paying attention to which faucet we used,
and got the "needle jet" by mistake. The jet hit the
funnel and sprayed stuff everywhere: in our hair,
on our shirts, and all over the counter. We wiped
everything up with paper towels and tossed them
in the wastebasket. Then, as things slowly dried
out, the fun began! Combing our hair or just rustling
our shirts was like little cap pistols going off. As
students drifted into the classroom to ask the
teacher about grades, we would sidle over to the
wastebasket and give it a kick... whatever parts
had dried by that moment went off with a BANG!

Highly educational....



Bob Masta
dqatechATdaqartaDOTcom

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

 

[Lord Garth]

"Adrian Godwin" <adrian.110504@ntlworld.com> wrote in message
news:vj3ee2-ccn.ln1@smaug.toynbee.org.uk...

Thot <brigatti@cox.net> wrote:
Hello,
I am very interest myslef in being able to log and analyze in a
computer
overnight heart rates with the Poalr chest band or other systems.

can you post more details?


I've been thinking of something similar and bought a cheap (Aldi)
HRM to experiment with. This uses a similar method to the (uncoded)
Polar units, in this case a 5.3kHz burst. Seems to be close enough
to work with standard gym machines.

If you google back through the sci.electronics newsgroups you'll
find a few comments about the Polar units - the reciever apparently
uses a Neosid encapsulated inductor as the receive coil.

Given the audio frequency, it seems to me that a very cheap logger
could be built by constructing a circuit built around an open-cored
inductor and tuned to about 5kHz. Such a circuit will show 5kHz
pulses even on an insensitive scope if held close to the HRM band.
Add, perhaps, a little more filtering and a microphone preamp and
then send the resulting signal to an audio recorder - one of the
tiny flash-based music players with a microphone socket would be
convenient, but experiments could be done with a PC sound card.

Finally, extract the 5kHz pulses from the recorded data file
using software on the PC. I don't know what effect compression
will have on the recording, but it would be easy to generate
a test file without building any hardware at all.

-adrian

That Polar unit was affecting the resistance setting on the treadmill I was
running
on. The thin person on the next machine was using a low resistance
appropriate
for her height, weight and age...when she got next to mine, all my setting
changed
when "my heart rate" dropped and my machine adjusted for my low heart rate!

I set it to manual and finished the 5 miles.

 

[Lord Garth]

"Bob Masta" <NoSpam@daqarta.com> wrote in message
news:42149ffb.933311@news.itd.umich.edu...

On Wed, 16 Feb 2005 21:17:51 GMT, "Lord Garth" <LGarth@Tantalus.net
wrote:


"Fred Abse" <excretatauris@cerebrumconfus.it> wrote in message
newsan.2005.02.16.21.03.19.860325@cerebrumconfus.it...
On Sun, 13 Feb 2005 20:27:29 +0000, John Woodgate wrote:

Yes, prone to 'autonomous energetic disassembly'. (;-)

I once made some copper acetylide at school.

Nitrogen triiodide was good, too...

Amazing what you could get away with back then.

--
Then there's duct tape ...
(Garrison Keillor)


Hmm, I used to make ammonium tri-iodide in HS...
It worked well on the erasers with the expected pops,
but be careful.


Indeed. On the last day of the semester in HS chemistry,
the instructor allowed my buddy and me to make some
after class. We were having a hard time getting the
precipitate to pass through the filter paper, so we hit
on the bright idea that maybe a little added water
would help wash out the clogs. Only trouble was that
we weren't paying attention to which faucet we used,
and got the "needle jet" by mistake. The jet hit the
funnel and sprayed stuff everywhere: in our hair,
on our shirts, and all over the counter. We wiped
everything up with paper towels and tossed them
in the wastebasket. Then, as things slowly dried
out, the fun began! Combing our hair or just rustling
our shirts was like little cap pistols going off. As
students drifted into the classroom to ask the
teacher about grades, we would sidle over to the
wastebasket and give it a kick... whatever parts
had dried by that moment went off with a BANG!

Highly educational....



Bob Masta
dqatechATdaqartaDOTcom

We would put it under the desk leg...I wonder if the iodine stains are still
there?

 

[gwhite]

Dave wrote:

Fred Bloggs <nospam@nospam.com> wrote in news:421339E8.3050102
@nospam.com:



Spehro Pefhany wrote:
On Wed, 16 Feb 2005 00:50:42 GMT, the renowned "Thomas Magma"
somewhere@overtherainbow.com> wrote:


Are you talking MICS (Medical Implant Communications Service)?


Polar is (Swiss) a manufacturer of wristwatch-Heart Rate Monitors
(HRM) that are used by people working out. They have a separate
transmitter that straps around your chest, and a receiver in the
wristwatch. They're a consumer product, albeit a niche one. Their
manuals are a bit.. opaque.


The battery in the wrist watch is a consumer changeout, but the
transmitter must be returned to the service center when the battery
dies- every two-three years or so- it is a sealed unit.


I'd like to see a consumer of a S410 change the battery. It is a bitch
and is a testament to cheap shit/unobtainable customer service.

Polar is cheap crap, with .009mm AL metal type battery cage and soft
plastic, coupled with nessicity for complete dissasembly - separation of
LCD panel from PCB! Short battery life.

I would have paid hundreds of dollars for the 6 month battery life of
this POS, if I didn't have the nuts to change it myself 4 times. In two
years. The plastic tabs that hold the battery are wearing out. Short
battery life + expensive HRM + needing to line up the 20+ graphite pads
on the display to the PCB = fuck you polar.

A $12 Chinese Timex is a bargain (battery changing wise) compared to the
this abomination.

Shop around.

Venting, thanks!

I won't buy a Polar because I don't want to send the chest strap in to get the
battery replaced. I bought a Nashbar HR monitor for $35 and I replace the
batteries myself. Perfect. At $35 bucks it is nearly throwaway.

To be a little fair, hapless assemblers can screw up cheststrap seals, and sweat
then destroys the transmitter. It has happened and I suspect this is why Polar
does things the way they do.

 

[Rich The Newsgropup Wacko]

On Wed, 16 Feb 2005 21:09:37 +0000, Fred Abse wrote:

On Sun, 13 Feb 2005 20:27:29 +0000, John Woodgate wrote:

Yes, prone to 'autonomous energetic disassembly'. (;-)

I once made some copper acetylide at school.

Nitrogen triiodide was good, too...

Amazing what you could get away with back then.

We used to electrolyze water, and demonstrate "rapid exothermic
recombination". ;-)

I was trying to dissolve some sulfur in some CS2 once, and used
the logic that if you heat up the solute, it helps speed solution.
Until the CS2 reaches its flash point, of course. It's a weird
feeling, being engulfed in a ball of blue flame. =:-O

Cheers!
Rich

 

[Jonathan Kirwan]

On Sat, 19 Feb 2005 03:31:40 GMT, LEDMan@3v.invalid (LED Man) wrote:

Looking to drive a white superbright led (1-4) from 1.5v to 2.5v
battery, led requires 3.3v @ 20ma, is there a suitable small circuit, or
single chip device

An NPN, a 1.5V AA battery, two resistors, a capacitor, a diode and a simple,
hand-wound threaded toroidal. D2 can be a diode-connected 2N3904, a 1N4148, or
a Schottky like a 1N5817-1N5819.

V+ V+ V+
| | |
| | |
| )|. .|( (about 50" of
| )| |( magnet wire
| )| T1 |( for both
| + )| |( windings)
--- | |
- B1 | | D2 R2
--- \ +---|>|---+---/\/\---,
- / R1 | | 220 |
| \ 2200 | | |
| / | | |
| | |/c Q1 | --- ~
| '------| 2N3904 --- C1 \ / ~
| |>e --- 100uF --- LED
| (B1 > 1V) | | |
| | | |
gnd gnd gnd gnd

It will drain a AA battery fairly completely, before quitting.

Jon

 

[Fred Abse]

On Thu, 17 Feb 2005 21:37:10 +0000, Rich The Newsgropup Wacko wrote:

On Wed, 16 Feb 2005 21:09:37 +0000, Fred Abse wrote:

[quoted text muted]

We used to electrolyze water, and demonstrate "rapid exothermic
recombination". ;-)

I was trying to dissolve some sulfur in some CS2 once, and used the logic
that if you heat up the solute, it helps speed solution. Until the CS2
reaches its flash point, of course. It's a weird feeling, being engulfed
in a ball of blue flame. =:-O

Remember the refractive index experiment, using a hollow prism, filled
with carbon disulfide and monochromatic sodium light from a piece of salt
in a Bunsen flame a few inches away?

Don't spill the CS2!

--
Then there's duct tape ...
(Garrison Keillor)