@robert-hh said in ADC sensors on external PSU: @Alephus Connecting the sensor to the input should not raise the voltage measure at that connection. So it must be something else in the set-up. after a while i did a few more tests and found something: of all ADC1 pins, all behave properly except P19 and P20 (guess wich 2 i was using) a friend analized my problem as well and detected that those 2 pins where not "floating", and after analazing the datasheet he assumes its because they are the only ones with pullup/pulldown internal resistors. So for now i have a solution however i still dont understand is why, after all, they are tecnicaly valid Pins pins in the datasheet

@KiraKiraSoul said in Expansion Board 3.0 Vin (3.5-5.5V) pin: In other words, is the input voltage regulated in any way on the expansion board? No. It's the same signal, just differently labeled. When connected to USB, you should see 5V at that pin coming from USB. Otherwise you can supply a xxPy device at that pin with input voltages from 3.5-5.5 V.

@SiMoS-IoT Thanks. Given the state of Pycom documentation and the large quantities we are going to need we have decided to build our own solution, so the power feed issue will go away. I really like the approach to power Pycom have, but the fact we can't get any documentation on how it functions, other than a few system calls, means we can't take it into production. I'll probably still keep using it, but only for interests sake.

@curtis-hendrix I have no spec but I once tried to connect a small LCD display to that power pin. That was an instructive failiure. Even 400 mA is optimistic (may only be reachable at the limit of 5.5 V Gpy supply). You can safely use that 3.3 V pin to supply some I²C chips but nothing that needs power.

To close this post, I wanted to say that the issues I found in the deep sleep shield, have already been reported before in this forum. My mistake was not to do an exhaustive search before posting. Conclusion: the deep sleep shield has quite a few problems when powered by a lipo battery. *bradnz hace 12 meses For any one interested, or has this issue in the future I have resolved this by doing the following: Rolled back firmware to 1.7.9.b3 Used version 1.0.0 of the deepsleep.py file from github. Works fine now.* post1 post2 post3

@sslupsky AFAIK, the enable pin is not accessible.