Pixhawk 1 and Lumen functionality

Hi Eliot and the Forum:

So a client of ours is trying to find a replacement for a Pixhawk 1 on an old BlueROV. We have some of the MRobotics Pixhawks that were available up until recently. Before shipping one of those out, I’m trying to understand the context of the note that was in the last run of Pixhawks that BlueRobotics shipped:


" Please note! Due to a chip incompatibility, these units do not function with our Lumen Lights."

Does anyone know the context of this note? I’m assuming it is only related to late-production Pixhawk 1s, but I would really like to understand this issue better before shipping a Pixhawk that might not work correctly to a client.

When the Pixhawk supply crunch hit a couple of years ago, did anyone end up using the mRobotics Pixhawks that were available, and if so, can they comment on whether they had issues? Thanks.

Walt Holm
Mission Robotics

Hi @wholm,

We got a batch of Pixhawks manufactured, and the supplier used a PWM driver with less timing consistency than would normally be expected for that component (not sure if it was counterfeit or just a bad batch or something), so the pulse durations have fluctuations. That works out ok for applications with some inertia (like thrusters and servos), but is quite annoying for a light source like the Lumen because it causes visible flickering.

Unfortunately we only found out about the issue after we had received the boards, and reworking them with replacement PWM drivers would have made them prohibitively expensive. If I’m remembering correctly we stopped selling those Pixhawks at the time, but then once the Navigator was generally available we decided to at least list them as available (with an appropriate warning), in case there were people who wanted a reduced price and didn’t mind the sub-par PWM output performance, since they still work fine as flight controllers.

I’m not aware of any Pixhawks having that issue other than that specific batch.

Thanks Eliot for that information. We’re going to go ahead and ship a mRobotics Pixhawk 1 to that customer of ours, I’ll report back here if he experiences any issues with it.

Walt Holm
Mission Robotics

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Just to check up on this thread. Was there any problems regarding using the Pixhawk 1 with Lumen R2 lights?

Well, we never heard anything back, so I’m assuming the mRobotics Pixhawk 1’s worked fine.


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