LIDAR Sensor has arrived!

[seg9585]

Just wanted to share that a new LIDAR (laser radar/rangefinder) is out on the market from "PulsedLight3D" for $90 -- Class I laser so it's FIRST legal. Just arrived today in the mail, and I hooked it up to my Arduino:



Did some initial testing via I2C, seems to be very accurate between ~20cm and 650cm (as far as I could test it tonight without finding a larger room), 0.5 deg beam width

Here's a snapshot of my Serial output with distance in cm (~100 Hz samples averaged and output at 5 Hz), sitting on my desk facing up to the ceiling.


http://pulsedlight3d.com/
We're going to have fun with this!

[AllenGregoryIV]

We got ours today as well. Similar results to your tests. Very excited about this little guy.

[runneals]

Being a geospatial geek, this is TOTALLY COOL!!!!!!!

[TylerStaudigel]

This might be a newbie question, but this can be connected to the robo-rio via the I2C and programmed in labview to give us the distance. Right. I haven't done much work dealing with I2C and am not sure what to expect.

[seg9585]

Originally Posted by TylerStaudigel

This might be a newbie question, but this can be connected to the robo-rio via the I2C and programmed in labview to give us the distance. Right. I haven't done much work dealing with I2C and am not sure what to expect.

The sensor has 2 output formats: I2C and PWM. I have tested via I2C and it works great. To use PWM, you'd need to create a low-pass filter to smooth the output which could then be read by the roboRio analog input.

I will be coding up a Java Class this week to interface with I2C on the roboRio, which I'd be happy to share.

[tech2077]

In case anyone is interested, I wrote up a java class for this, you can use the start/stop functions to use the built in updater Timer, or use the update function to only poll distance when needed.
LIDAR.java

[PaulDavis1968]

Ordered! I have been drooling over this for 6 months. And we might have a use for it. I was going to buy it for my self regardless. If it works out I will get one for the team so we have two.

[dellagd]

Based on the datasheet it seems this wouldn't work on polycarbonate, since it transmittance is just as high at 905nm as it is in the visible spectrum, and the laser would mostly go right through. I really don't know much about LIDAR systems, so does anyone else with more experience know if this would be the case?

[PaulDavis1968]

Originally Posted by dellagd

Based on the datasheet it seems this wouldn't work on polycarbonate, since it transmittance is just as high at 905nm as it is in the visible spectrum, and the laser would mostly go right through. I really don't know much about LIDAR systems, so does anyone else with more experience know if this would be the case?

I asked this question on their forum.

https://groups.google.com/forum/#!forum/pulsedlight3d

[Jared Russell]

Polycarbonate doesn't have 100% transmittance for near IR, but it's still very high. You will get a small amplitude return from polycarb, which will be higher if there are scratches or dirt on the surface, or if you are getting specular returns from other light sources. You can configure the LIDAR-Lite to present either the strongest, first, or last return to you, and I'd expect whatever is behind the panel to be the strongest return the vast majority of the time (but not always).

Experientially, LIDAR sucks for detecting transparent objects and requires lots of signal processing and integration of multiple scans over time to have any chance of accurately detecting a transparent object.

[seg9585]

FYI, I have detected distance to transparent windows with moderate levels of success. I'd assume polycarbonate behaves similarly, but would have to do more testing. We are programming up the LIDAR against the roboRio tonight so I'll try it out.

[NotInControl]

For those that have these sensors, what is the jitter on the returned distance value you are receiving for a given period of time?

Does the returned value go unstable at any point in operation (i.e bouncing around different values) or is it pretty accurate, to what level of accuracy have you noticed? (i.e +/- 1 cm)?

Are you using the RoboRio or other embedded device to power and read the sensor?

Thanks for your response.

Thanks,
Kevin

[dellagd]

Originally Posted by seg9585

FYI, I have detected distance to transparent windows with moderate levels of success. I'd assume polycarbonate behaves similarly, but would have to do more testing. We are programming up the LIDAR against the roboRio tonight so I'll try it out.

Not quite. Glass is actually opaque to IR light, just like a piece of metal would be, while polycarbonate behaves just the same as it would in the visible spectrum (for a good bit). Things change when you move to different wave lengths, like, for instance, a black trash bag is totally transparent.

[seg9585]

Originally Posted by dellagd

Not quite. Glass is actually opaque to IR light, just like a piece of metal would be, while polycarbonate behaves just the same as it would in the visible spectrum (for a good bit). Things change when you move to different wave lengths, like, for instance, a black trash bag is totally transparent.

True for some IR bands but not near-infrared. Glass transparency doesn't drop off until approx 2000nm but this laser operates at 900nm.

One source:
http://www.molalla.net/members/leeper/transmis.png

[dellagd]

Originally Posted by seg9585

True for some IR bands but not near-infrared. Glass transparency doesn't drop off until approx 2000nm but this laser operates at 900nm.

One source:
http://www.molalla.net/members/leeper/transmis.png

Fair enough, then I'm curious how the LIDAR is operating as well as it does. Interesting.