PIR (passive infrared) sensors are used in many applications for motion sensing. In our article PIR Sensor Circuits we looked at how a typical 12VDC PIR sensor can be used in common applications.
Such PIR sensors are typically used in home security systems to be connected directly to burglar alarms and as such have a couple of disadvantages. The first is their size as they are quite bulky, and the second more important disadvantage is that they output a positive signal when no motion is detected, and no signal when motion is detected.
PIR sensors are usually configured in this way so that if a bad guy cuts the signal cable, the alarm will be triggered. However, this means some electronics are required if you want to use the signal to directly trigger a light, siren or other motion detecting output.
KC7783R PIR Module
Pictured above is the KC7783R PIR module which offers the perfect balance of relatively low cost, small size, and ease of use. Unlike a standard PIR sensor, this module will output a 1/2 second high signal whenever it detects motion, and nothing the rest of the time. It is therefore very simple to integrate into any standalone motion detector application – e.g. shed alarm, CCTV camera trigger, automatic security lighting, and so on.
The KC7783R is just 25 x 35mm in size and supplied with a ball lens already fitted. It is prewired with three wires: input+, input-, and the output signal. The input voltage range is 4.7V to 12V, though 5V is suggested. The standby current draw is just 300uA (0.0003 Amps), so it is very efficient. This PIR module will detect motion at a range of up to 5 metres.
We will soon be adding some articles giving example system designs using this excellent PIR module.
Buy KC7783R Modules
The KC7783R PIR module is available for around £7.50 including VAT. Click here to buy KC7783R now.
To download and view the KC7783R datasheet (PDF) click here.