LIDAR Sensor has arrived!

[Joe Ross]

Can you try in C++ as well (either the accelerometer or the LIDAR). Java and C++ share a lot of code, and that might help pinpoint where the issue is.

[tech2077]

Originally Posted by Joe Ross

Can you try in C++ as well (either the accelerometer or the LIDAR). Java and C++ share a lot of code, and that might help pinpoint where the issue is.

Verified to have the same error.

[marshall]

We picked up one of these... it seems very sensitive to glossy/reflective surfaces. Much more so than the lidar system we yanked from a Neato vacuum robot. Not sure what others are seeing. We haven't dived into the sample code yet beyond running it.

[Tom Line]

We have 2 of these and played with them today with LabVIEW. We have been unable to get them to work with the native I2C port on the roborio. However, we have them working just fine on the MXP expansion I2C with identical code. We've pinned them out, swapped the lasers themselves, and still have zero luck with the native port.

The native port DOES know the sensor is connected. We received read and read/write errors stating that the device is busy. This is different that the 'resource not found' error we get when the device is not plugged into to power or not plugged into the I2C.

On the MxP I2C port we are reading then writing in alternating 20 ms loops. We lowered the timing of these loops incrementally until we started getting errors. At 10 ms polling we receive all zeros, at 15 ms we receive data, so 20 ms is where we are (50 hz). We average 5 loops in a moving average filter and the data looks very good.

I know we can improve this by doing the write then checking for the ready bit, but this worked just as well and gave us a resolution we're happy with. Plus after 6 hours of banging our head against the native port we were already pretty frustrated.

We have noticed that when the sensor was aiming at the ceiling and our flourescent lights we got highly inaccurate results.

[Merfoo]

How would one program the LIDAR Sensor for use via DIO in Java?

[marshall]

Originally Posted by Merfoo

How would one program the LIDAR Sensor for use via DIO in Java?

I don't know that you can. It's designed to work via PWM output or I2C. The I2C implementation should be pretty similar to the arduino example on their website. The PWM setup will likely just be reading analog input values but don't quote me on that.

[tech2077]

Originally Posted by Merfoo

How would one program the LIDAR Sensor for use via DIO in Java?

Two possible methods:

1. Use a low pass filter and read through analog (less programming but requires a resistor and capacitor connected to the output, or
2. Directly measure the pwm pulse and convert the timing to distance (more programming, but the sensor just drops in and works)

I plan on eventually writing up a pwm based class due to the problems teams have had with this sensor and the onboard i2c port.