Security & Surveillance
( See also "FM Transmitters", "Sirens & Sound", "Strobes & Flashers" )

K8 - Light Alarm Price Photo Docs
Detects very small amounts of light and sounds the piezo alarm. Put it in your cash box or cupboard. Uses Darlington photo transistor MEL12 and 14011 IC.

K13 - Sound Activated Tape Recorder Switch Price Photo
Can be adjusted to turn on your tape recorder through its REMOTE plug. Has feedback and delay circuit for robust operation. Very sensitive. Proven circuit. Needs 6V plug pack for most stable operation.

K21 - Two Station Intercom Price Photo Docs
Simple two wire intercom. Each unit with its own speaker, microphone and amplifier (LM386.) Can be modified to a hard wired "bug". With 4 strand ribbon cable the power can be sent to the remote "bug" unit from the receiving unit.

K26 - Fibre Optic Audio Link Price Docs
Allows you to send sound through plastic 1mm fibre optic cable. Matched transmitter/receiver pair. Two circuit boards with a microphone at one end and a speaker at the other. 14 feet of fibre optic cable supplied. Will work over 200 meters.

K30 - PIR Movement Detector Price Photo Docs
Circuit designed around a recently developed movement IC. Circuit utilizes PIR detector and a light dependent resistor (LDR) to provide an optimized circuit that will detect motion up to 6 metres away. Operates on 9-12 VDC. Note that the PIR sensor & the PCB-mounted fresnel lens fit on the other side of the PCB; the solder side. This is to allow the unit to be mounted inside a container with the detecting lens poking out and the controls facing inside the box.

K33 - Tape Recorder Switch for Telephone Price Photo Docs
This kit uses a FET to switch on a tape recorder when the phone is picked up. It will work with low voltage tape recorders as low as 1.5V. It requires the REMOTE & MIC jacks of the tape recorder to be available. Plugs are provided.

K76 - PIR module, cable connection, (assembled), KC7783 PricePhoto Docs
A fully assembled and tested miniature PIR module with only 3 connections: Power, Ground & Output. Rated for 5 - 10VDC input power. Has 2 1/2" cable attached as shown in the photo. Uses RE200B PIR sensor (datasheet page 1, page 2), KC778B movement detector IC (datasheet page 1, page 2) and PCB mounted Fresnel lens. Output is an active high pulse of approx. 0.5 seconds and remains active as long as there is motion. Range up to 3 metres. Sensitivity is fixed. Small size, 25 x 35mm (1" x 1.35").