ESP32 not getting power from servo rail

Hardware Pixhawk family
1

Hello,

I wanted to power an ESP32-CAM onboard from the power rail. I have a 2A Power Module powering the Pixhawk 2.4.8. But when I connect the power pins of the ESP32 to the servo rails, the voltage on the rail goes to 0.6 V (which is like the voltage across a forward biased diode). BUT Mavlink reports a healthy 4.9V on both Vcc ad Servo rails which indicates that the issue is after the internal voltage sensing network, so its probably related to some protection feature on the servo rails or on the ESP32 itself.

I also have an FS iA6B connected to RCIN but it has 4.9V and the drone responds to RC commands. So I guess the RCIN pin is independent from the servo rail (maybe it is connected to Vcc?)

Does anyone have any idea whatโ€™s going on? I now think its probably on the ESP32 side as Iโ€™m pretty sure there is a diode in the power path so that the circuitry inside wonโ€™t affect the rails as can be observed by the mavlink messages and servo rail header measurement discrepancy.

Thank you very much

2

The servo rail on a pixhawk is not powered from the pixhawk, it needs its own power supply.

1 Like
3

Like I said, I have a power module and the rail shows 4.9V on a multimeter. Or is it like that and collapse as soon as current is drawn?

4

Powering the Pixhawk

5

Oh okay, thanks. The presence of this phantom 4.9V misled me.