There was an article in Circuit Cellar 6 - 12 months back which used a seismic sensor to detect human foot steps, probably worth a look. regards Lee Mclaren -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Richard Graziano Sent: Wednesday, 17 December 2003 12:41 AM To: PICLIST@MITVMA.MIT.EDU Subject: Re: vehicle detect Have you though about vibration sensing and band pass filtering? Cars an= d truck cause vibrations in the ground. Remote sensors could detect the vibrations and wireless transmitters could send the data to wherever. ----- Original Message ----- From: "Tony K=FCbek" To: Sent: Tuesday, December 16, 2003 4:27 AM Hi, James Cameron wrote: >Ideas wanted. I live on a farm, and would like the approach of vehicles >announced in two houses. But I don't want to have false triggers caused >by thunder, cows, sheep, kangaroos, or insects. BTW this really should be [EE:], atleast at the moment as no one has suggested using a plasma core with jiggawatts yet. This will probably work very well: http://www.semiconductors.philips.com/pip/KMZ10C.html Some general info: http://www.semiconductors.philips.com/acrobat/various/SC17_GENERAL_MAG_2.= pdf Particulary look at page 68 'Example 2 Traffic detection': Here's a taste: "The sensor modules also proved sensitive enough to detect and distinguish motorbikes (even with engine, frame and wheels being made of aluminium), which produced the following roadside spectra." I.e. it's possible to detect even which type of vechicle, with enough dat= a collection one should be able to detect speed and make of the car to ;) And as a bonus they even placed the sensor at the side of the road in one test (instead of under the middle of the road). Hey maybe it's possible to store the spectra (curve) from each 'known' vehicle and 'annouce' even who, instead of 'someone', is comming :) Also there is an extention to the family, whic is intriguing for detectin= g vehicles :) http://www.semiconductors.philips.com/pip/KMZ52.html "The KMZ52 is an extremely sensitive magnetic field sensor, employing the magnetoresistive effect of thin-film permalloy. " /Tony -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics