40 KHz Ultrasonic Range Meter
How to measure range using frequency? Of course, You need a device called ultrasonic range meter. In this project it uses the ultrasonic frequency of about 40 KHz. The range measurement based on the time which the ultrasonic returns from the measurement object.
In order to measure the range to an object, ultrasonic transmitter-receiver system used. Three digit 7-segment LED used to display the range of measurement. The transmitter circuit of the ultrasonic generated by using two 555 timer ICs. The ultrasonic signal which was received with the reception sensor is amplified by 1000 times (60dB) of voltage with the operational amplifier with two stages.
This ultrasonic range meter made with the double sided printed board.
Read more: http://hobby_elec.piclist.com/e_srm.htm
