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PX4 Hardware designs
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Pixracer: FrSky Telemetry cable #54

Open LorenzMeier opened 8 years ago

LorenzMeier commented 8 years ago

@kd0aij @nickarsov Do we need to connect the 5V signal to the receiver? That might be problematic and we might want to only connect S.PORT and GND.

kd0aij commented 8 years ago

I was not connecting 5V from pixracer to the X4R receiver in my testing, except of course via the RC input cable. Its purpose is to supply power from the RX to sensors on the bus, so the sensors do not source 5V. The S.port + pin on my X4R-SB is connected directly to the + line on the servo bus, so there shouldn't be a problem if the same supply is connected to both pins.

LorenzMeier commented 8 years ago

No, there would be a massive problem. @nickarsov If you connect the 5V rail you can fry Pixracer if a servo is back-driven (which happens on planes and servo gimbals).

Building drones is an art. The seemingly simple is quite complex to get right.

LorenzMeier commented 8 years ago

@pkocmoud FYI: You need to ensure your S.PORT cables do not connect the 5V line.

LorenzMeier commented 8 years ago

We have seen quite a few people connecting servos to the receiver even if connected to the autopilot. The most famous case that brought a plane down this way was Tridge.

kd0aij commented 8 years ago

@LorenzMeier Thanks, I see now they are 2 different supplies, and that this would tie the VDD_5V_RECEIVER and VDD_5V_PERIPHERAL supplies together, disabling the back-emf protection provided only for the RX supply.

nickarsov commented 8 years ago

Don't forget TVS103 !

pkocmoud commented 8 years ago

The manual is updated.