Home made radar/proximity sensor.

OK, I made a home made radar/proximity sensor from a device called BirdContro shown here http://pestcontrol.netfirms.com/page19.html (This device is discontinued). This device can detect motion from within 30 feet radius (360 deegres). It can drive a speaker level output up to 20 watts and 120 db, its sensitivy is ajustable. The unit is actually a radar device since it has to transmit/ping packets and receives them back and determine the difference, there is a transmitter and receiver in the unit. The output drives/supplies power (speaker level) for about 10 seconds making crazy bird sounds. If you connect it to 6 volts, the output can drive 5 volt relay and if you connect it to 12 volts it can drive 12 volt relay. So what i did was i connected to a relay via a 2000uf Cap and a 5K (resistor) and added a diode accros relay coil. I connected the relay to one of my sirens. So now every time the device detects motion it drives my relay (in turn driving my siren) for about 1 second (constant). I took the electronic part of it and put its main board in a 3.5" by 3" box and mounted the box the box in the center under the dash, set the sensitivity to around 6 feet radius. It works great.... The next mod that i have in mind is to hook this relay ouput to my Alarm Brain to emulate a "warn away" signal (double pulse chirp). For now it only does one chirp. I have a question to those who have the real proximity sensor. If you set the sensitivity to max , what is the radius distance? Does it give a prewarn signal? or it sets a full alarm blast? Thanks,

Manokat, that's pretty clever! What you'll want to do is to go to the wires of your alarm's shock sensor, and mess around with those. Typically there are four wires: red: positive black: ground green and blue: negative when shock sensor is bumped Typically, depending on the brand of alarm, if the green or blue receive a pulse that is shorter than one second, the alarm will emit its warn-away chirps. If the pulse is longer than one second, the alarm goes into full trigger. To do what you want, I'd say these are the necessary steps: 1. Test the function of each of the shock sensor wires. 2. Connect a piece of scrap wire to chassis ground, arm your alarm, and touch your wire to the shock sensor's wires. Experiment and find out what it takes to make the alarm go into warn-away mode. 3. Somehow set up your homemade sensor to emulate what the shock sensor does.

Thanks for your inputs kenmci and  Chris Luongo. I did this mod just to    make the BirdContro device more usefull than just sitting in my basement   storage. Essentially any kind of motion detector device that is lying      around idle at home can be used in the car.

I have an Autopage RS850-LCD. Its two stage shock sensor has four pin Red     (+), Black (- / ground), Green (Zone 1 or Warn away input), and Blue Zone  4 ground trigger).                                                         Now i have not had a chance to check how my sensor works,  but i guess all two stage shock sensors are the same and in order to "emulate" a "warn away" signal i just have to apply a ground signal to Green wire less than ONE second. Is this correct? I guess i just have to change the Capacitor to 1000uf and Resistor to 10K for my relay so that the relay will be active for halfa second, supplying ground to Green wire for about half a second.

I'll give it a try this weekend.To bad I can only make this device emulate either "warn away"  or "full blast" but not two stage.I prefer full blast when someone actually touches the car.That leads to my next question. Has someone seen a schematic diagram of hand "touch switch" that uses negative as the trigger origin?Or is there any alarm add-on module that will make the car body as  touch switch?Essentially a touch switch that can use car body as the trigger area.I found this http://www.uoguelph.ca/~antoon/circ/alarm2.htm but not using ground as the trigger.As well as this http://www.asian-east.com.tw/ae-502.htm but this one uses its on leads as the trigger which may not be ground signal.