Pixracer: Potential power sequencing issue on GPS port

LorenzMeier commented 8 years ago

@nickarsov @pkocmoud The airspeed sensor browns out on boot. The most likely reason is that the power sequencing goes bad during boot.

It only happens when powered through battery, it doesn't happen when powered through USB.

How does the 5V rail plot look like on boot? Please do not offer any judgements, I just want to see the real data. 3 plots:

1) USB power applied 2) Battery power applied 3) A sequence of wiggling the power connector of the battery

LorenzMeier commented 8 years ago

So it seems like connecting battery "kills" the sensor. Which seems absurd.

Maybe the device went into a bad state when we powered it reverse.

RomanBapst commented 8 years ago

Correct, having usb connected the driver works. Connecting power without even removing the usb cable kills the driver.

pkocmoud commented 8 years ago

5vduringboot

Power Up using Battery, connecting and disconnecting USB, Battery remains connected until the end.

LorenzMeier commented 8 years ago

@pkocmoud It would be great if you could try to repro with one of these: http://www.hobbyking.com/hobbyking/store/%5F%5F62752%5F%5FHKPilot%5F32%5FDigital%5FAir%5FSpeed%5FSensor%5FAnd%5FPitot%5FTube%5FSet.html

pkocmoud commented 8 years ago

"repro"? I have the 3DR Version to test with.

RomanBapst commented 8 years ago

@pkocmoud That would be great.

pkocmoud commented 8 years ago

5vduringbootonmaster Recorded while loaded with Master.

pkocmoud commented 8 years ago

No Brown Outs Detected. The PixRacer power supply is solid during our tests.

LorenzMeier commented 8 years ago

@tumbili If you comment out this line, does it work for you? https://github.com/PX4/Firmware/blob/0e0c1302e41abc75e83bd3b0a324bead952f8a16/src/drivers/meas_airspeed/meas_airspeed.cpp#L228

RomanBapst commented 8 years ago

@LorenzMeier same thing

LorenzMeier commented 8 years ago

Odd. It has to be somewhere there.

LorenzMeier commented 8 years ago

So my 2nd board has an all working sensor. We have now 3 boards:

1): 0-1.8V on the 5V rail 2): Romans board: 5V on GPS rail, but no airspeed sensor signal when powered via the 3DR power module 3): Completely working when powered at 5.3V through a lab power supply

The only thing I haven't tried yet is what happens when the sensing / ADC pins are active, as I have no power module.

I certainly have a bad board, not sure yet about the causality of the other two items.

RomanBapst commented 8 years ago

@LorenzMeier Is 5.3 a magic value? Does is also work with 5V?

LorenzMeier commented 8 years ago

Your power module is outputting 5.3V. Which is why I chose it.

nickarsov commented 8 years ago

Yes, it works with 5V too, because the USB can't supply 5.3V

LorenzMeier commented 8 years ago

Nick, rather than speculating it would be good if you could work out how I can return the electrically bad board to your for inspection.

nickarsov commented 8 years ago

Lorenz, Speculating with what...I just answered to Roman. And yes, you can return it back to me for inspection at: Nick Arsov 8 Konstantin Irechek str., bl.1 4700 Smolyan Bulgaria

LorenzMeier commented 8 years ago

Thanks, will do! I'm closing this as it seems board-specific.

LorenzMeier commented 8 years ago

@nickarsov the part you identified has 5V on one side and 0V on the other.

LorenzMeier commented 8 years ago

Soldering looks sketchy. I will rework it later today or tomorrow.

LorenzMeier commented 8 years ago

This was in fact the airspeed sensor. Still have one board with 1.8V on that port, but that is probably manufacturing QA. Replaced with: https://github.com/PX4/Hardware/issues/55

pixhawk / Hardware

Pixracer: Potential power sequencing issue on GPS port #49