Hi all, I think these ideas on using a potentiometer are great! But I am still thinking of the mechanical part, how do I reliably hang/slot a heavy thing on the arm of a potentiometer/quadrature encoders? Any ideas? I have just found out that the cost of the Accelerometer-ADXL202AE is unbelievably high at USD 18 while the cost of a Electolytic Tilt Sensor is also high at USD 4 -> 5. In addition, when I think of real life application, the sensor will Not be able to raise an alarm if the car is jack up simultaneously from the front and back. So this is another disadvantage. From there, a fren of mine suggested using Ultrasonic sensor to detect the distance between the car and ground underneath. I think this is possible too, but again, ultrasonic sensor is not cheap either. Maybe someone could suggest me one which is sufficiently good and economical. Or maybe, like Jinx suggested, use infra-red sensors to detect the tyre/suspension movement? But, will that be reliable on broad daylight? Or pets that sleep underneath at night? Any other ideas to raise the alarm whenever a car is being towed? Have a nice day. Rgds, Pang ----- Original Message ----- From: "Dwayne Reid" To: Sent: Tuesday, May 21, 2002 8:43 AM Subject: Re: [EE]:Tilt sensor > At 09:43 AM 5/20/02 +0100, Michael Rigby-Jones wrote: > > > > >I guess a potentiometer with a weighted arm hung off the end would do the > >trick? > > Even better: one of those fairly inexpensive quadrature encoders from > Bourns: 256 pulses per rev with ball bearing shaft. Reset an up-down > counter to 0 when the ignition is turned off and sound the alarm when the > count exceeds some pre-set value. Using a quadrature encoder and up-down > counter helps ensure that swaying and wind gusts don't cause the counter to > just climb to the trigger value. > > I'm not sure if the sensor from a mouse has enough resolution but that may > also be worth a try. > > dwayne > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu