Simple Laser range finder

[bogalark]

hi
Request for help in making laser distance measurement/module for 200 feet or approx 70mts.
Generally a laser range finder contains sender, receiver and time measurement module to find the distance.
can any one help me out with the complete components to be used and the schematics, including the optics to be used...

 

[Cyparagon]

First post asking for entire blueprint to rangefinder? Not gonna happen, sir.

I won't say it's impossible to built one from scratch, but it's a very advanced project. Might I suggest building a pointer or projector first?

 

[bogalark]

First post asking for entire blueprint to rangefinder? Not gonna happen, sir.

I won't say it's impossible to built one from scratch, but it's a very advanced project. Might I suggest building a pointer or projector first?

thank you,agreed with you sir..
coming to the pointer,i have been through few components like collimator, laser diode of 650nm CW laser and 855nm pulse mode laser diodes and few of the laser diode drivers for the above...im not perfect but just trying to make one. i felt pointer section is abit easy compared to the rest of receiver section when i had gone through few block diagrams in the net... not able to make out,needed help for the same...:thinking:

 

[Sigurthr]

If you're just going to point at random things and measure the distance I have no idea, but if you wanted to measure the distance of a fixed target I think you could do it somewhat "easily".

You can use a one-shot to simultaneously trigger a short pulse to the laser and a count down start (or even a reset - even easier) to a simple binary counter driven by a high frequency oscillator. Feed the receiver's HI output (which indicates the return pulse has arrived) to the counter stop (can be a simple soft latch that holds the binary counter's oscillator input high). Read the counter's state and multiply by the time period of the oscillator, then divide by the speed of light in air and then divide by two. I have no idea what frequency you would use, you would need to determine how long a pulse should take and work out a frequency which will have enough clocks for good resolution but not so fast that you risk the counter resetting or timing out. Most simple counter ICs max out at 8192 time periods. You also need to be mindful of any propagation delays in your signal paths and logic.

Good luck, you'll need it!

 

[bogalark]

If you're just going to point at random things and measure the distance I have no idea, but if you wanted to measure the distance of a fixed target I think you could do it somewhat "easily".

You can use a one-shot to simultaneously trigger a short pulse to the laser and a count down start (or even a reset - even easier) to a simple binary counter driven by a high frequency oscillator. Feed the receiver's HI output (which indicates the return pulse has arrived) to the counter stop (can be a simple soft latch that holds the binary counter's oscillator input high). Read the counter's state and multiply by the time period of the oscillator, then divide by the speed of light in air and then divide by two. I have no idea what frequency you would use, you would need to determine how long a pulse should take and work out a frequency which will have enough clocks for good resolution but not so fast that you risk the counter resetting or timing out. Most simple counter ICs max out at 8192 time periods. You also need to be mindful of any propagation delays in your signal paths and logic.

Good luck, you'll need it!

thank you very much, can you help me out with any schematics of the module or of any kind like that plz...

 

[Sigurthr]

I don't know of any modules, though I don't doubt there are some available commercially. Heck, I think they make range finders for golfers and land surveyors.

Schematics would be a bit above what I could reliably do; I've only recently begun working with timer ICs (not counting the 555 of course) and there is a lot more info and research needed to take the basic design theory that I posted and put it in to a schematic.

Not that we don't have some members who might be capable of this kind of device but why don't you look to an electronics forum for help with this? The Laser in this device is such a minor part that for all intents and purposes it could be replaced with an LED and the circuit would work electrically the same (sans no return signal of course). In other words, find help with the main part of the citcuit elsewhere then come here and find the laser specific info you need.

 

[bogalark]

I don't know of any modules, though I don't doubt there are some available commercially. Heck, I think they make range finders for golfers and land surveyors.

Schematics would be a bit above what I could reliably do; I've only recently begun working with timer ICs (not counting the 555 of course) and there is a lot more info and research needed to take the basic design theory that I posted and put it in to a schematic.

Not that we don't have some members who might be capable of this kind of device but why don't you look to an electronics forum for help with this? The Laser in this device is such a minor part that for all intents and purposes it could be replaced with an LED and the circuit would work electrically the same (sans no return signal of course). In other words, find help with the main part of the citcuit elsewhere then come here and find the laser specific info you need.

thank you, i tried but wanna know the power ratings and current limiting factors to design the component in the circuit,so...trying to know the specs of laser and receiver module first...

 

[bogalark]

hi
if not complete schematics of individual components can i get the readily available modules so that i can integrate them to get a laser range finder like 1).laser diode transmitter which includes the laser diode(CW or PW) including the collimator and the laser diode driver
2).laser receiver which includes receiver lens,photo diode and conversion unit(i am not sure, i mean light signal to voltage(electrical signal)).
3).time descriminator/ time to digital converter for measuring the time between start pulse and received pulse(any microcontroller/chip).

if yes, for measuring a distance of 70 mts, can anyone specify the specifications that are appropriate to make a module..

thanks in advance...

 

[Cyparagon]

People around here usually expect you to do at least 30% of the work in your own projects.

 

[lasersbee]

hi
if not complete schematics of individual components can i get the readily available modules so that i can integrate them to get a laser range finder like 1).laser diode transmitter which includes the laser diode(CW or PW) including the collimator and the laser diode driver
2).laser receiver which includes receiver lens,photo diode and conversion unit(i am not sure, i mean light signal to voltage(electrical signal)).
3).time descriminator/ time to digital converter for measuring the time between start pulse and received pulse(any microcontroller/chip).

if yes, for measuring a distance of 70 mts, can anyone specify the specifications that are appropriate to make a module..

thanks in advance...

You are trying to build a sensitive Electronic/Optical system
and yet you seem to have no basic knowledge of Electronics
or Optics.

It is akin to me stating "I have a screwdriver... can someone
give me a drawing or modules to build a 747"

I would suggest that you do some in depth Google searching
for Basic Electronics and Laser Range Finder or LIDAR circuits.


Jerry