i am biulding a micromouse robot.i'm confused which circuit shuld i do for ultrasonic sensor to detect wall

Answer 1

Hi Chista
I don't know what you are using for a controller or how big your mouse will be, but I think that if you use a 556 dual timer chip. Half set for about 5 Hz and the other to about 38 kHz as a transmitter and a two 38 KHz transducers one for receive and one for transmit you will get what you are looking for.
Use an opamp with a filter that passes only high frequencies to amplify your signal and charge a capacitor on the output. This will give you a voltage on the capacitor that varies with the strength of the return echo. Biggest problem is keeping the transmit pulses out of the receive circuit.
Personally I am going to use a flashing LED and a Photo transistor for the same thing on a hobby robot I am designing right now. Easier to shade the photo transistor from the out put signal of the transmitter.

Answer 2

Are you building one from scratch? Acroname (and I, tinmanrobotics, if you are in So Cal) carry the Devantech SRF05 ultrasonic range finders. they are easy to set up if you're running any micro com. Just send a trigger and count the time till the return pulse.