Jon, You may find that activating the locks at 10 mph will have undesired results when you are moving the car in a driveway or parking area, and still have passengers to load. Some vehicles use something like: >15mph for at least X seconds, where X is in the range of 2 to 5 seconds. It's easy enough to tune your software after your try it a while, of course. The speed sensor (pulse generator) in some Japanese vehicles of that era switches a 12 volt reference to ground, generating pulsed DC. I'm not familiar with your model, though. One way to find out would be to connect your meter (set to DC volts) and watch the signal voltage when moving the car verrrry slowly. You should be able to watch it toggle between ~12 and ~0 if it's pulsed DC. If not, try switching your meter to AC volts and driving the car. An AC signal should increase significantly in voltage with greater speed. My first "real" PIC project was a device to apply a 10% correction to an electronic speedometer. Each incoming cycle was timed, and the outgoing frequency was increased by 10% on a cycle-by-cycle basis. It had to make each trip through the main loop in ~30 instructions to avoid jitter, and did everything in software (no timers) using 16-bit variables. At the time I found it quite a challenge to get everything done with only 30 instructions, and also to make sure the main loop always took the same number of cycles, regardless of what was happening. Definitely a good learning experience. An 8-pin 12F629 should be able to do the job nicely. Have fun! Randy www.glitchbuster.com ----- Original Message ----- From: "Hulatt, Jon" To: Sent: Tuesday, September 23, 2003 10:54 AM Subject: Re: [EE] (automotive) frequency trigger > hehe, no, really 10mph. I want to lock the doors when i get to 10mph, and > then unlock them when the engine turns off. Seems to be a good second pic > project, and also a simple anti-hijack tool. which is a risk in that car. > > -----Original Message----- > From: Eric Schleicher > To: PICLIST@MITVMA.MIT.EDU > Sent: 23/09/2003 13:15 > Subject: Re: [EE] (automotive) frequency trigger > > So you rally meant 100 MPH didn't you... > > > > What type of vehicle is it? > > > > A Nissan Skyline GT-R (1997 model) > > > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu