The circuit has been simplified even more; the active circuitry inside the modified zapper is a single TIP-31 NPN transistor, available at any Radio Shack. A computer provides the timing of the zaps and rest periods, as well as the frequency, using the UART in all PCs. The included perl script is meant only for Red Hat Linux 6.1 on a PC, though it shouldn't be too difficult to port to other architectures and operating systems.
Since Dr. Clark made the fruits of her lifelong research available free, the circuit and program are also free, as per the terms of the GNU Public License, which you will find following the code in the zapper perl script
This version of the script only generates about a 20KHz signal, since using stty I can only set the speed to 38400. If I could figure out the IOCTL I'm sure it's possible to set it to somewhere around 60000, which would give a 30KHz signal (remember that 1 bit is 1/2 a cycle). (Update 2002-01-29 found the command 'setserial /dev/ttyS1 spd_hi which does that, sets the speed to 56K when the 38400 speed is requested.) I tested the output with an oscilloscope which showed a clean square wave about 2 cycles/graticule at a time setting of .1ms/graticule. It uses the letter capital U, which generates 5 cycles (1 start bit [0], the pattern 01010101, 1 stop bit [1], which together makes 1010101010).
The workings of the circuit, as far as my limited knowledge of electronics allows me to understand, is like this: 9 volts from the battery gets sent through an LED, followed by a 1K resistor, to the red handhold. If the black handhold is also held, and there is sufficient conductance in the subject's body, the resulting current will flow back through the collector-emitter circuit into ground. This happens only when the square wave coming in from the computer is high, at which point it generates a positive bias at the base of the transistor, causing base-emitter current to flow gating the collector-emitter current. The negative half of the RS232 signal is blocked by the diode, and the transistor is protected by the voltage divider set up by the two 1K resistors. I'm not really sure that's necessary, but it got rid of some negative spikes I could see with the oscilloscope; can't tell you why, I'm not that bright. Maybe someday I'll really study electrical engineering and be able to grok this stuff. Note that the way the circuit is constructed, there is no real need of an on-off switch. Nothing happens unless there is some conductance between the two handholds, and there is a positive signal from pin 3 to pin 5 at the RS232 connector. The LED in series with the resistor I thought was a nice touch, too. It lets you see how much current is actually passing through your body. Notice how much brighter it lights with a fresh battery, and your hands wet.
Though I think it's a good design, still it doesn't seem to work. I caught a cold a few weeks ago, and it had absolutely zero effect on it. I don't know if it's because the design is flawed, or if the whole idea is rubbish altogether.
Until I get around to doing a better job, I will include a description of the circuit and as much of a parts list as I can put together. PLEASE NOTE that ANY USE OF THIS MATERIAL IS AT YOUR OWN RISK. YOU CAN BURN YOUR BALLS OFF WITH THIS FOR ALL I KNOW. IT HAS NO PROVABLE MEDICAL BENEFITS, yadda yadda yadda.
The handhelds are 1/1-4 by 6" solder tubes, found in any home improvement center. At the same place, you can buy the ends, which are 1" PVC slip caps (not threaded). Drill a 1/8 inch hole at the center of the two caps, and mount a red binding post in one and a black binding post in the other. Solder a wire from the binding post to the inside of the tube; you'll need to scratch a fresh area into the brass using a pocketknife or better, some emory cloth, if you want the solder to stick. And it takes quite a bit of heat to melt the solder in the tube. Most butane irons can provide the heat. Then force the caps down onto the wide end of the tube. If it fits too loosely (wish I had that problem!) use some adhesive. Maybe crazy glue would work. Me, I had to hammer the damn things on. The Radio Shack part number for the binding posts is #274-0661. For the wires, you can use some of the pieces from the breadboard wiring kit, #276-0173, or from spools like #278-1226.
Connect the zapper box to the computer with a standard straight-through modem cable, Radio Shack 260-0117 or equivalent.
The box itself is #270-0213, plus any old 9-V battery, and a solderless breadboard #276-0175 attached with dual-sided foam tape, #640-2344. Attached with holes drilled through the lid are the other two binding posts from the pack of 4, one red and one black (see above); a 9-pin D-sub socket #276-1538, attached with 4-40 screws and nuts, #640-3011 and #640-3018; and a red LED from the pack #276-1622 with a socket (not really necessary) #276-0079.
I will attempt to draw the box using ASCII art:
Top of 270-0213 box from underside:
-------------------------
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| ||||---o----. | That |||| is the resistor,
| / \ | the o is the LED.
| / ..... | |
| o .|. \ | o | The dots are the RS232 jack,
| | | | | | the o's are the binding posts.
| | | | | |
------------------------
| This is a yellow wire
| from pin 3 (xmit) of the RS232 jack
| to socket G3 of the circuit board.
| | This is an orange wire from pin
| | 5 (ground) of the RS232 jack to
| | Y22 of the circuit board.
| | | This is an orange wire from
| | | the anode of the LED to X22
| | | on the circuit board.
| | | | This is a yellow wire from
| | | | the black binding post to
| | | | D8 (TIP-31 collector)
~ ~ ~ ~
Bottom of box, seen from above.
~ ~ ~ ~
| | | |
| \ / |
| \/ |
| /\ /
| / \/
|---------|---/---/\-| Battery red (V+) to X23
V+ -|-. | / / !+-- GND Battery black to Y23
| .-------+--' / .| LED to X22, RS232 GND to Y22
| | / |
| \ / |
| \/ |
| /\ |
| / \ |
| / \ |
| / | | Transistor plugs into C7,8,9
| ---. -/-------+-- | White jumper E9 (emitter) to Y9
| | |. / | | Yellow wire terminates at D8
| ---. ----- / == | Orange jumper E7-F7, 1K J7-Y7
| / { | 1K from H5-H7
| {/ | Diode F3-F5, yellow terminates G3
| |
| ~ ~ |
| \/ | Battery black and red to X23, Y23
|--------------------|
| | 9V battery compartment
----------------------
Reasonably complete parts list follows. Actually I bought more than I needed, and some of this is redundant, but if something's missing above, you'll probably find it here.
| Radio Shack part number | Description | Quantity |
|---|---|---|
| 2761653 | Diode asst | 1 |
| 2761539 | 9pos subd hood | 1 |
| 2760175 | EXP-350 socket | 1 |
| 2700213 | BX 5.75x3.6x1.29 | 1 |
| 2762017 | TIP31 transistor | 1 |
| 2711118 | PK5 1K 1/2W | 1 |
| 2781226 | 45' #18 strnd UL | 1 |
| 2760173 | BBD wire kit | 1 |
| 2761538 | 9pos subd socket | 1 |
| 6402344 | PK8 DBL FOAM TAPE | 1 |
| 2761622 | PK20 assorted LEDs | 1 |
| 2740661 | PK4 binding posts | 1 |
| 6403018 | PK30 4-40 hex nut | 1 |
| 2761537 | 9POS subd plug | 1 |
| 6403011 | PK42 4-40 RH SCRW | 1 |
| 2760079 | PK5 LED SNAP-HLDR | 1 |
| 6400017 | 0.5oz 60/40 solder | 1 |
| 2600287 | port adapter 25F-9M | 1 |
| 2600117 | 6' RS232 cable 9M-9F | 1 |
| 2740734 | stack banana plugs | 2 |