DISCLAIMER:

The information contained in this file is for informational purposes only. We take no responsibility for the use of this weapon if built according to the designated plans.

PRINCIPLE:

The Ultrasonic Hell Device emits a very high (approx. 14-22kHz) sound which is almost unheard by most people. However, it is still very loud and although almost nothing is heard, it causes discomfort and a headache if the sound is sustained for a period of time (approx. 1 minute)

PARTS:

(1) 555 timer chip (NE555, LM555, or any other 555 variant will do)
(1) 8-pin socket (optional)
(1) 470 ohm resistor
(1) 1k PCB-mount potentiometer
(1) .01uf capacitor (.01mfd is the same thing)
(1) Perfboard/Breadboard/whatever to put it on (about 1.5"x1.5")
(1) 9v battery clip
(1) 9v battery
(1) 8 ohm speaker (the bigger the better!)
(1) SPST push-on/push-off switch

SCHEMATICS:

                                 +9v     +------------> Speaker -
                                  ^      |
                             470  |      |
                   +---------/\/\-+------+-------+
                   |              |8             |
                   |       +------+------+       |
                   |      7|             |4      |
                   +-------+             +-------+
                   |       |             |
                   | \     |             |3
This right  -->    +>/     |     555     +--------------> Speaker +   
here is the          \    6|             |
1k port.              +-+---+             |2
                       |   |             +-----+
                       |   |             |     |  
                       |   +------+------+     |
                       |         1|            |
                       |          +-----|(-----+
                       |          |   .01uf    |
                       |          v            |
                       |         -9v (GND)     |
                       +-----------------------+         
                                  

Note: The numbers next to the 555 connections are the corresponding pins.

FURTHER CONSTRUCTION:

Cut one of the battery cords in half and attach the switch to the ends. This will make it easier to turn off and on. To make the device even easier to operate, put it in a case. Plastic, metal, cardboard, whatever. Just make sure there's a place for the sound to come out (drill a few holes in front of the speaker.)

PHYSICAL LAYOUT:

The conventional layout of this device is the switch installed in the top of the case, with the circuit board attached to the bottom, the battery next to the circuit board, and the speaker over the battery. This is a handy way to lay it out and looks pretty inconspicuous.

Another way is the miniaturized version. No perfboard is needed for this, just the components. Instead of a 9v battery, lithium battery(s) may be used. The best speaker to get for this is a 1" tweeter- expensive but SMALL and LOUD.

Attach the components directly to the chip, thus making an extremely small circuit. A good way to do this is to put the 470ohm resistor and the 1k pot on the top side, the .01uf cap on the bottom side, and to attach jumper wires between the 4&8 pins and the 2&6 pins. Then simply attach the battery & speaker connections to where they belong.

FINAL NOTES:

With parts purchased from Radio Hack, this circuit (not including case) should cost you around $4. With mail-order/surplus prices you should be able to assemble it for around $1.50. This device works extremely well in a quiet environment with a lot of people around. When operated for a full thirty minutes it causes people within about a 10' radius to develop intense headaches.

Make sure that when you are using it that you wear some sort of ear protection as you will be at the center of the sound.