This exactly true. About a year ago, I received one as a gift and, since it worked like $hit, I tore it down to see how they were able to make a laser range finder for about $50. The answer was, they didn't. It was just a laser pointer attached to a sonic (ultrasonic) piece of junk. The laser showed you what the sound was likely to hit - that is all.

thanks alot sir,new thing to think...even should consider this as one of the imp concepts...

 

Laser distance measuring has recently become feasible on the cheap, due to faster micros and smaller/cheaper SMDs etc.

Here's a laser distance masuring tool;
http://www.boschtools.com/Products/Tools/Pages/boschproductdetail.aspx?pid=DLR130K

And even things like cheap robot vacuum cleaners can have laser distance scanners like this one from a Neato brand robot, that scans the laser in a circle to get multiple distance readings from all directions;
http://www.protechrobotics.com/proddetail.php?prod=3903499

hi,thank you...
i had gone through the complete products(laser distance module) by bosch, they are providing for almost all ranges at affordable cost.. but trying to make out actually what they are doing and trying to make one home made product on own..need suggesstions on components and schematics...

 

what if i consider a 650nm laser diode with CW mode,with a laser driver and a collimator for the transmitter part..any views on the components and a help on schematic of the driver...and for receiver, PIN diode or APD would make sence i think but worried about the optics to detect the laser at a distance of 70 meters..

any schematics on this will surely help me...

 

hi
if not individual components,are there any modules available so that we can combine them i.e like transmitter laser module of pulse wave diode/CW diode which is more appropriate to measure a distance of 70 mts, in the same way receiver section or something like that..please let me know...

thanks in advance

 

I don't think you will have much success trying to make one from parts.

It's getting close to RF technology, where you are working with incredibly small signals and very high frequencies.

The signal you will receive after 70m reflected, has travelled 140m and will be almost non-existant at your receiver photo diode.

So that part alone will need good optical lenses and construction, and highly shielded high gain amp.

If you think you can buy a few cheap common parts and plug them in a breadboard and make this work then I think you will be disappointed...