Maxbotics MB1240 XL Maxsonar EZ4 sensor issues in v2.49

I have been playing with the v2.49 APMRover firmware. The manual/learning & auto modes work perfectly.

However, I have added one Maxbotics MB1240 XL Maxsonar EZ4 sensor, to the A0 pin of my APM2.5.

I checked out the instructions for adding the sonar sensors appears. The params described at the following link: … r-sensors/

appear to be outdated. But, based on the notes for the RANGE_FINDER related params, I things up.

Under the tuning menu, I do see the readings from the sonar sensor, so the sensor appears to be working.

But, when I switch to Steering mode, the wheels turn right and the rover goes in a circle, even if there are no obstacles. I am unable to use the steering radio controls any more, other than throttle forward.

So, I switched to learning mode; made it learn some way points by flipping the CH7 switch. When I move it to auto mode, it does not follow the waypoints. The rover seems to have a mind of it’s own.

Anyone seen this?

Any help is greatly appreciated.


Hi Ganesh. I have seen this post I just haven’t gotten to it yet. Could you please attach a dataflash log (.bin) when the issue occurs and I’ll try to have a look on the weekend.

Thanks, Grant.

Hi Grant,

Thanks for the offer to help. It’s going to be raining all day for the next few days and I will be unable to do this over the weekend either. I will be able to try this after on or after the 26th of June. As soon as I get a chance to retry this, I will post the file you’ve requested.

Thank again,