improper data with Arduino

[Jerwinprabu]

I have tried the simple_connect example with Arduino Mega. Because I can't use Arduino UNO for checking results. Here, I have tried to use Serial1 for checking lidar data, but the data is improper.

Output:

theta: 200.25 Dist: 01659.00 Q: 47
theta: 50.80 Dist: 01700.00 Q: 47
theta: 340.80 Dist: 02213.00 Q: 47
theta: 73.33 Dist: 02208.00 Q: 47
theta: 211.89 Dist: 02222.00 Q: 47
theta: 111.44 Dist: 02229.00 Q: 47
theta: 79.00 Dist: 02234.00 Q: 47
theta: 204.55 Dist: 02238.00 Q: 47

Is there any way to solve this problem?

[Titibo26]

i can't see what is improper ? I got the same.

[Jerwinprabu]

Can you check the output carefully. The data is not continuous data.

If the first data is theta: 200.25 Dist: 01659.00 Q: 47 then next it should be 201, 202, 203 etc. But it is directly from 200 degree to 50 degree.

It is a random data. It should give the data from 0 degree to 360 degree. So I am asking solution for getting the proper data.

[Titibo26]

Yes i know, i have the same output. I'm not sur if it's a problem. it seems to be the normal behaviors because in the window app "fram_grabber" wich is given in the source code, they sort the array of point by the angle value. It is not clear how the lidar should work and i can't find anthing about this, but a solution is to sort output value by yourself in your code (as the arduino library doesn't do it).

It would be way better to have output allready sorted by angle... Maybe its a problem related to the serial link, if the µC can't handle so much and so fast data some are deleted in the buffer ?

You can try to contact slamtech here : support@slamtec.com they are fast but its really hard to have real answer on their products...

If you find a solution, post it here ! :)

[Pilooz]

Which kind of Lidar do you have ?
A1 or A2 ?
Your data seems to output from the A2 version.

[Jerwinprabu]

RP LIDAR A1M8 360 Degrees Laser Range Finder- 6 Meter Range

[gunnicus]

RP LIDAR A1M8 360 Degrees Laser Range Finder- 6 Meter Range

Hello sir, do you mind share some details how to connect arduino mega to RP LIDAR? I'm using PR LIDAR A1M6 REV6, I can't get any data from the lidar to arduino, all I got is timeout error.

[Jerwinprabu]

@gunnicus Suggesting you to use Raspberry pi 4 (2/4/8 GB RAM)

[gunnicus]

@gunnicus Suggesting you to use Raspberry pi 4 (2/4/8 GB RAM)

Thanks you so much sir for your reply..it looks like my rplidar is a bit different compare to yours
I followed this diagram but never got it working...I'm not sure if this diagram is correct. This is from their A1M8 datasheet...

[Jerwinprabu]

@gunnicus The New RP Lidar is a compact version but the configurations and protocol is same as the old Version. You can try this

https://github.com/robopeak/rplidar_arduino

[gunnicus]

@gunnicus The New RP Lidar is a compact version but the configurations and protocol is same as the old Version. You can try this

https://github.com/robopeak/rplidar_arduino

Thank you sir, that's very kind of you. Yes basically I did that, but no luck, I can spin the lidar if I write analogWrite(RPLIDAR_MOTOR, 255) inside loop(), but all the commands timed out...

[Jerwinprabu]

@gunnicus Can you specify your Application or you can share the code to check the issue, It will help me to provide the proper suggestion.

[gunnicus]

@gunnicus Can you specify your Application or you can share the code to check the issue, It will help me to provide the proper suggestion.

Hello Sir, please see the attached pitcure it is my wireing. The code is simple_connect example, the only change I made is to use Serial1 instead of Serial : lidar.begin(Serial1); . Thank you so much for your help.

[gunnicus]

@gunnicus Can you specify your Application or you can share the code to check the issue, It will help me to provide the proper suggestion.

Hello sir, I did more test, the issue seems to be the power supply for the core. I measured the voltage between the vcc5v and groud, the voltage is only 4.1v, I checked the spec it says min voltage is 4.9v. If you run the lidar with Arduino mega, what is the voltage supplied to the core interface?

[Jerwinprabu]

@gunnicus You can use external power supply for 5v and make a Common Ground between 2 different source.

[Pilooz]

Hi,
I confirm what @gunnicus said. Arduino does not deliver enought power to lead the lidar.
Consider using an external poxer supply in the good way. For example you could use a 5/5A (which is 25W) block.