Infrared based ranging ~ 1m range - Ideas?!

[kapilp]

Hi,

Has anyone attempted to build an IR based ranging setup for distances around 1meter?

What I plan to do is:
1: Astable Multivibrator to drive the transmitting LED
2: Current to Voltage converter at the receiver with adjustable gain and a bandpass
3: Sample and Hold type amplifier for the output stage

Can someone please confirm the viability of the above scheme?!

Potential issue which I can foresee is an inadequate range.

AND: I am fully aware of Sharp IR rangers and their capability (excellent!!) but dont want to use them. They cost around INR800-INR1000, while the above scheme should cost me about INR200 maximum.
ALSO: I dont want to use Ultrasound.

Thanks a lot!

 

[betwixt]

You will find it extremely difficult to use IR in reflective mode over short ranges. The reason is simply the tiny delay between transmission and reception is difficult to measure. In fact it may be much less than the response time of the IR source and detector.

For low cost, a better method might be to send a continuous narrow IR beam at an angle and from a position a short distance away, note where the beam lands. A greater distance will show as greater displacement from the source position.

Brian.

 

[kapilp]

@ brian

do you mean 'triangulation' ?

If yes, could you please elaborate on a way to implement such a scheme ... just the basics ...

Thanks