hi all,
i need to control the speed of the car..(if my car is near by an obstacle i should reduce the speed,at a certain distance my car should be stopped and when that obstacle is removed,at a certain distance my car should start again).to do this i need to have som sensors.can any1 tel me which sensor i can use and som ideas?
The ultrasonic sensors directly don't give the distance, they calculate the time interval between sending the signal and receiving the echo to determine the distance to an object.You must use a simple formula to calculate the distance.But you need to do some code stuff with micros.
For simplicity use IR.
Ikalogic has done nice experiments with IR visit his site.
if i use ir sensor how do i link the sensor with any µc?i prefer using atmel 8051..is it possible?n how do i measure distance?(i need to stop the wheel only at a certain distance nto as soon as i find the obstacle)...thanks for all ur help...i think i can do it easily...
Using IR you can't measure the distance.Using IR you can "stop" or "start" the car.
Just make a IR circuit like ikalogic did using an opamp.Tune the circuit to a desired distance.Ex 30cm,So when the obstacle in front of 30cm you can get a signal to the micro.After micro get this signal start your PWM to reduce the speed.So you can stop your vehicle linearly with the distance without stopping suddenly.