Albuquerque Business Daily

What technology would I need to alert a gadget of something specific in its vicinity?

I am trying to work out wjat type of technology I would need to send a signal (warning) that a specific item is in range of an item say 5 meters. Like a transmitter and receiver type devise. Any ideas?

Public Comments

1. ya this is a dual stage motion sensor for car alarms but it has standard 12 volt negative outputs for each zone http://cgi.ebay.com/DEI-508D-DUAL-ZONE-MOTION-SENSOR--CLIFFORD-PYTHON-VIPER_W0QQitemZ220299758722QQcmdZViewItemQQimsxZ20081023?IMSfp=TL081023108002r8283 this is a link to a e bay ad but you can find this at any local car stereo shop the dual stage ones work better than the singal stage
2. Now a days most cars(modern) are using a technology,which alerts with a high sonic whisling sound when ever some one passes near by.Please contact a workshop for information.
3. It depends on the properties of the item, body warmth for example.
4. 1) video capture. If the picture changes, alert the device. 2) infrared. send out a pulse of infrared light. wait for it's reflection. Measure the time delay and divide by 2 to get distance. 3) proximity (capacitive). As the dielectric changes due to foreign objects between / near two plates, the capacitance changes. 4) ultrasonic. just like infrared, but uses sound too high to hear. 5) RF. radiate a radio signal. Watch for its reflection from metal objects.