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Lightware LW20 I2C with Pixhawk 2.1 ArduCopter 3.5.3

(René Desgagnés) #1

Hi everyone,

I got an early Christmas present. I bought myself a Lightware LW20 i2c version. I tried to follow the guide at but the sonar distance is always 0. I have double-checked and triple-checked my settings and everything seems fine. As an experiment, I connected the LW20 to a Raspberry Pi and I enabled the following stream $1,ldf­ . I can then read from the i2c bus which gives me results like these ldf,0:0.87 for example.

Does anyone else have a LW20 i2c version that works ?



(Nikita) #2

Hello, I had problems with Lightware SF11 and Pixhawk 1, and recently I noted PR to fix I2C issues with it and it helped me, so either wait for new firmware or build latest yourself.


(RobGowans) #3

The issue with the Pixhawk 2 seems to have been resolved with changes to the code as Nikita pointed out above. I’m trying to verify it personally. I will let you know what I find.

(René Desgagnés) #4

Hi Rob,

I compiled the master version and now the lw20 i2c works fine. Thanks Nikita for the tip.


(RobGowans) #5

Good to hear. It looks like this fix will make it into 3.6 and be backported to Copter 3.5 and Plane 3.8.