LIDAR RPM and PWM reports

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LIDAR RPM and PWM reports

Postby vic7767 » January 24th, 2016, 11:13 pm

I have found a couple of tools for testing the Neato and Botvac LIDAR units outside of the robot. The first tool is a small PCA with a Teensy 2.0 mounted on it as well as jacks to plug in the Lidar motor and 4 pin Lidar circuit board connector. The board is powered via the USB port on a PC. This device is built and sold by GetSurreal and you can go to their website to order one for $29.95.

Once connected to your PC the Teensy board will power up and start spinning your Lidar. The default speed is set at 300 RPM but there are several commands that can be sent to change different settings to what you prefer. I set mine up to display the RPM and PWM data on a poor performing Lidar. What I discovered was a defective main turret bearing. By adding a drop or two of lubricant I could get the RPMs up close to 300 but it would then drop back down. This will require a bearing replacement to perform correctly.

Here is an output example that was captured using RealTerm.

RPM: 244.97 PWM: 1023.00
RPM: 245.00 PWM: 1023.00
RPM: 244.23 PWM: 1023.00
RPM: 243.97 PWM: 1023.00
RPM: 245.19 PWM: 1023.00
RPM: 245.98 PWM: 1023.00
RPM: 245.58 PWM: 1023.00
RPM: 244.42 PWM: 1023.00
RPM: 245.08 PWM: 1023.00
RPM: 243.59 PWM: 1023.00
RPM: 243.00 PWM: 1023.00
RPM: 297.66 PWM: 802.85
Here is when the oil was dropped onto the bearing
RPM: 298.63 PWM: 801.01
RPM: 298.58 PWM: 801.28
RPM: 299.25 PWM: 799.94
RPM: 298.81 PWM: 800.95
RPM: 298.63 PWM: 801.48
RPM: 298.64 PWM: 801.60
RPM: 297.69 PWM: 803.84
RPM: 297.84 PWM: 803.79
RPM: 298.53 PWM: 802.72
RPM: 299.13 PWM: 801.66
RPM: 300.02 PWM: 799.99
RPM: 299.94 PWM: 797.91
RPM: 299.34 PWM: 799.18
RPM: 299.27 PWM: 799.72
RPM: 299.50 PWM: 798.44
RPM: 299.86 PWM: 797.57
RPM: 299.80 PWM: 797.85
RPM: 298.05 PWM: 802.20
RPM: 297.94 PWM: 802.62
RPM: 298.08 PWM: 802.77
RPM: 298.25 PWM: 803.64
RPM: 297.66 PWM: 804.06
RPM: 296.69 PWM: 805.86
RPM: 298.47 PWM: 804.72
RPM: 297.81 PWM: 806.26
RPM: 298.02 PWM: 806.02
RPM: 297.00 PWM: 808.39
RPM: 297.69 PWM: 807.26
RPM: 297.47 PWM: 807.99
RPM: 298.48 PWM: 806.14
Lidar controller
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Re: LIDAR RPM and PWM reports

Postby shirgal » January 25th, 2016, 10:57 am

Vic thanks for sharing, I just ordered one with lidar mounter,
Cheaper controller option is temporary out of stock, just the $32.95
Last edited by shirgal on January 26th, 2016, 5:27 am, edited 2 times in total.
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Re: LIDAR RPM and PWM reports

Postby vic7767 » January 25th, 2016, 12:54 pm

shirgal wrote:Vic thanks for sharing,
Just wait for a few hours and I will be sharing a URL to some free software that contains an app using the Teensy XV Lidar controller to map a room !
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Re: LIDAR RPM and PWM reports

Postby glnc222 » March 3rd, 2016, 11:37 pm

SLAM Software

To use the mapping data from such a device in making an entire robot guided by lidar, one possible source for code is (SLAM -- Simultaneous Location and Mapping). One entry there is TinySLAM, how to do it in 200 lines of C language code.
Besides the lidar input robots use tachometer data from drive wheels, and also computer mouse-like sensors reading motion across the floor.
Most of the software in this field appears proprietary but there are many sources and tutorials on the mathematics employed. I suppose of use mainly by advanced engineering students.
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Re: LIDAR RPM and PWM reports

Postby robotmaker » February 5th, 2017, 4:18 pm

easiest and the cheapest way is to use a 3.1 volt power supply and ttl to usb board
or arduino board and terminal program

mostly the arduino or tennsy board is for controlling rpm (300 rpm) and the boards act like a ttl to usb

about 3.1 volts will give very close to 300 rpm doesnt have to be exact just to see if your lidar is working
its very simple to hook up and use,also there is a GUI graph that shows a radar graph that shows the lidar is working

i sell lidars on ebay a lot and i use the same program plus a box to test lidars i sell
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