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Topic: Cheap laser distance sensor/meter (Read 33 times) previous topic - next topic

cr0sh

Well - I went and wrote up an article for my website. It's basically the same as above, but I did add some extra links for other methods/ideas - so you may want to check it out:

phoenixgarage.org || Low Cost LIDAR and Laser Range Finders: Where Are They?

Hope this link doesn't offend anyone (mods, let me know and I'll remove it)...

:)
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

Archelon


It may work, though price of interface board is more than range finder itself. My guess, interface board software decodes LCD display messages, leaving laser sensor / processing out of the picture. Probably, there is no easy way to hack a core.  Following their path, you even don't have to open range finder itself, just put a web-cam above and make video recognition from LSD display,  I think it would be possible for $150 project budget, but I would not call it "integration".

That sounds right! That's a good idea to put a webcam on top of it and I think it would work out quite good but the problem is that I just want to use the arduino and not a computer to get the distance data. As far as I'm concerned arduino can't handle graphic data that well :)

Archelon

Thanks for your reply cr0sh! You give a few options which sounds great but I'll think I'll go for the laser distance meter FLUX 411D and the onterface board I talked about earlier. I think the total cost for that "system" would be around 350 USD and I suppose it would work just as fine as the vaccum cleaner option if I attach it to a servo. I do also think it will work quite well in daylight as well, what do you think?
And while I'm writing I must ask you cr0sh, you wrote this
Quote
homebrew - is an option. What you are suggesting with the serial communications system is certainly possible; I would see if the serial output is already in some TTL serial (5V or 3.3V) format, first (instead of going through a special interface cable). How fast you can make those measurements, though, would be a question to find out about.

what do you mean by TTL serial?
in the interface board data sheet (http://porcupineelectronics.com/uploads/LR3_Data_Sheet.pdf) it says that the RX and TX uses 3V signaling. does that mean that I have to power the arduino in some special way?

Magician

Quote
I just want to use the arduino and not a computer to get the distance data. As far as I'm concerned arduino can't handle graphic data that well
Right, interface web-cam to arduino would be problematic. Same time I can't imagine application where arduino would need +-3 mm distance measurements data over distance 50 m, plus 2D. There is no memory even to keep this information, not to do anything useful.
I also have no clue, why this guys use  2D scan (using complex and high price mechanical hardware)   for vacuum cleaner, when for simple obstacle avoidance you only need couple laser pointers ($2) and video cam (could be low as $10).
http://coolarduino.wordpress.com/2012/07/28/visual-navigator-making-it-mobile/


cr0sh


Thanks for your reply cr0sh! You give a few options which sounds great but I'll think I'll go for the laser distance meter FLUX 411D and the onterface board I talked about earlier. I think the total cost for that "system" would be around 350 USD and I suppose it would work just as fine as the vaccum cleaner option if I attach it to a servo. I do also think it will work quite well in daylight as well, what do you think?


I can't say anything as far as whether it would work well in the daylight or not, but it will probably be at least as good as any of the other low-cost options. It does say it's designed for outdoor use, so maybe it will work OK.

Likely, it will work better for distance than the XV-11 sensor (it's distance is limited), but I doubt you'll get the same speed; the XV-11 spins 360 degrees quite rapidly (I think it can scan 10 full turns a second or so?); whereas that Fluke meter is going to have quite a bit of mass to move back and forth. I guess it will depend on how many scans you need and how fast your robot will be moving. There is also the possibility that it might be inaccurate (?) at close ranges vs. longer ranges. Something to keep in mind.


And while I'm writing I must ask you cr0sh, you wrote this
Quote
homebrew - is an option. What you are suggesting with the serial communications system is certainly possible; I would see if the serial output is already in some TTL serial (5V or 3.3V) format, first (instead of going through a special interface cable). How fast you can make those measurements, though, would be a question to find out about.

what do you mean by TTL serial?
in the interface board data sheet (http://porcupineelectronics.com/uploads/LR3_Data_Sheet.pdf) it says that the RX and TX uses 3V signaling. does that mean that I have to power the arduino in some special way?


Well - that board runs on 3 volts and outputs a USB signal; given that, it is likely that the meter itself is a 3.3 volt TTL logic device (that is, 3.3 volt = HIGH and 0 volt = LOW; the Arduino is a 5 volt TTL device - 5 volt = HIGH, 0 volt = LOW); instead of going from the meter's 3 volt TTL logic to USB then having to (somehow) convert that to something the Arduino can understand, it would be far simpler (assuming you can find the proper interface points) to just tap the 3 volt TTL serial signal from the meter directly, and forgo using the interface board (this would of course depend on what kind of connector and/or how that board hooks up to the meter). There may be some solder points directly on the meter's PCB that you could solder wires to. You would, of course, need to do level conversion for the signals to use them with the Arduino's 5 volt TTL levels, but there are plenty of solutions for that.

Otherwise, that converter board is designed to be plugged into a PC (and likely appears as a virtual COM port to the PC - if you can identify what TTL serial to USB chip it uses, and get the datasheet for that, you might be able to tap the signals easily from there).

The only way you can get away from -not- doing level conversion with the Arduino is to run it on 3 volts; unfortunately (IIRC), a standard Arduino - to run it at 3 volts - means you have to use the internal oscillator @ 8 MHz (which means you can't use the bootloader any more - so you have to program via ICSP).
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

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