Laser Distance Ranging

[samarsingla]

Hi, does anyone know how to use those small pen type lasers to make distance ranging setup. I need a rane of a few metres.
Thanx.

 

[audioguru]

Hi, does anyone know how to use those small pen type lasers to make distance ranging setup. I need a range of a few metres.
Thanx.

You can do it easily with a device that accurately measures angles then move the laser and make the measurement by triangulation.

Electronically it is complicated. Light is at an extremely high frequency so you cannot measure its reflection time, nor its phase difference. But you can modulate the laser beam with a high frequency then receive its reflection, detect the modulation and measure the phase difference due to the time it makes the round trip.

 

[Rolf]

Hi, does anyone know how to use those small pen type lasers to make distance ranging setup. I need a rane of a few metres.
Thanx.

I think it would be much simpler to use ultrasonic. Polaroid used it in their cameras for a range finder and sold an engineering research kit at one time. Maybe you could reverse engineer a Polaroid camera, they should be available as junk now for just a few $$.
If this don't appeal to you, then what about the IR tape measures that are readily available.

 

[samarsingla]

I intend to use it for some kind of surveylance so only laser would work. We intend to look at a very narrow area about few centimeters wide at a distance of about 2 metres. Like a hole. So sonar and IR won't probably work but what audioguru mentioned might be useful, though complicated.. measuring the time of flight of laser indirectly.

 

[Electrode]

I believe the term is Laser Interferometry....try looking that up.

 

[stevez]

Interferometry actually counts the wavelengths - so if you have a reference point to start with you can count the increments as an indication in the change in distance.