Laser Short Range (3') Finder

[Mwhynot]

I have a hobby sawmill that I want to add a range finder on. I want to accurately measure the distance from the carriage which holds the log to the saw. Distance will never be greater than 3ft. I am mechanical but when it comes to electronics I am alot slower. Been looking on Ali and Amazon at different parts etc but just dont have the skillset to match up the right hardware. Would require laser, small digital readout and a connection point for a small rechargable usb battery. Any help would be great. If this is the wrong forum for such requests just poke me haha.

Cheers
Mark

 

[rjenkinsgb]

It's not impossible, but the cost and complexity to get something working accurately at that type of range is crazy.
It is far cheaper to buy an off-the-shelf "laser tape measure" or industrial type range sensor.

The speed of light is 300,000,000 metres per second; 300 metres per microsecond.

Using "time of flight" measurement, one metre is just three nanosecond, or six nanoseconds round trip; measuring 0-6 nanoseconds is tricky, to put it mildly!
Another way involves modulating the laser with an RF carrier, then comparing carrier phases between the transmit and receive signals. That avoids the time measurements but uses complex demodulators, a CPU and a lot of maths..

Something like this is a lot easier!

https://docs.rs-online.com/3353/0900766b812ea399.pdf

 

[Mwhynot]

Ok...did think about the prebuilt measuring tools since I have several for aligning etc but they all have the laser emitting from the top of the device and not the left side. From the top makes reading display difficult since its sideways. Guess im out of luck.

 

[rjenkinsgb]

Could you add a 45' mirror to deflect the beam in the correct direction, plus using a relative reading / zero offset facility to allow for the extra distance?