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Topic: Lidar Lite V3 Accuracy Issue (Read 644 times) previous topic - next topic

xhr0428

I tested Lidar Lite V3 with Uno using the Garmin library I2C example. The specs says the reading accuracy should be within ±2.5cm for <5m range and ±10cm for the rest, but my result didn't match at all.

I pointed Lidar Lite towards a wall at different distances, recorded ~1000 samples at ~30Hz rate at each location and checked reading fluctuation:

Location     Fluctuation
1m             6cm
3m             9cm
7m             17cm
11m           52cm
18m           101cm

After 20m range, I could barely get any valid reading even though the measurement range should go to 40m written on the specs.

My connection exactly followed the diagram on the specs and I tried both default and maximum range modes.
http://static.garmin.com/pumac/LIDAR_Lite_v3_Operation_Manual_and_Technical_Specifications.pdf

Could anybody help me with this? Did I receive a faulty unit?

Thanks

mikb55

#1
Nov 17, 2019, 03:34 am Last Edit: Nov 17, 2019, 03:35 am by mikb55
Are you using a "70% reflective target" as per the documentation?
The device uses 905nm so there is no guarantee that something that appears reflective/white to you in the visible range is also reflective at that wavelength.

Are the values you see constant offsets or variations about a mean?


xhr0428

I pointed it at regular wall, I assume this should be a very normal use case.

The values are fluctuating around a mean.

mikb55


xhr0428

Yes, similar. His result seems to have less fluctuations than mine. Also my test beyond at 20m was like what he had for 40m, a lot of 1s and random erroneous values with several correct readings every now and then.

jremington

Point it at some different walls, and let us know what happens.

mikb55

If you fancy a bit of decorating visit your local hardware store and look for 'heat reflecting paint'. These are loaded with various metal oxides that reflect in the near infrared.

https://curve.carleton.ca/system/files/etd/252fd1b7-cb5f-4596-8469-c5e9c6b0857c/etd_pdf/f314d9e848600f52932bea16789c1d6f/cui-studyanddevelopmentofnearinfraredreflective.pdf

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