Design tips for Ultrasonic Ranging Project

Hi guys,

I would like to build a ranging device based on the 40Khz peizo electric transducers.

I had a look at EPE mag's/ John Becker's designs and they are indeed very simple.

However, he assumes that the users would like to have long range and thus his design has very little precision at short distances.

I need to build myself a device which will have a range of maximum 1 meters but be precise to a centimeter.

I would like to use this device for my micromouse project and it would be great is somehow I could have the sensors updating me atleast once every 300ms.

Do I need to take special care for using these sensors on a robot on the move ? I think special care need to be taken to reduce "ringing" of the transducers as much as possible ?

Related to this topic, I have heard that very old remote controls used to use these very trasnducers to transmit data, just like we use IR now a days ?
This seems to be very true, infact the 40Khz moduation freq most IR Remotes use seem to be an artifact of the bandpass freq. of these transducers ?

Do share some experiences, project links and advice

Well,
If you need better resolution and accuracy, use chirp modulation and demodulation.
Chirp could be LFM or any other kind of modulation.
However, you will need to use transducers with wider bandwidth than the 40 KHz ones you have. Check internet on broadening the response of transducers.
You will also need to know signal processing (IIR filters) and will need to use atleast a 16 bit fast controller.
Also search for chirp modulation and IIR filters on the internet.