B4R Question Totally puzzled with this - WeMos D1 Pins set to high arbitrary on one side of the board

[hatzisn]

Hi everybody,

I soldered the pins in a new WeMos D1 R3 mini and I tried to check with the voltometer if everything works fine. Here is what I 've found:

- 5V pin gives around 4,68V which I don't know if it is ok. Any suggestions are highly welcomed.
- 3,3V pins gives 3,29 which is almost perfect I think (the voltometer might be inserting a minor error)
- Pins D0, D5, D6, D7, D8 from one side of the board work as expected (when set to high 3,27-3.29V and when left without setting they have some voltage around 0,02-0,20 - I think it's ok).
- On the other side of the WeMos the party begins:

I started with D4 and this seemed to work fine. I set it to high, measured 3,28, I left it without setting and measured 0,08. I then moved to D3 and set it to high measuring 3,29V. I immediately changed the code to D2 and tried to set this high and normally I measured 3,29V but then I remembered I didn't check with out setting the D3 pin and removed the jumper wire from D2 and plugged it in D3 which without being set in the code to high had a value of 3.27. I added some code to check if there was a short circuit between the two pins and I have set D2 to high and D3 to low. I measured the voltage of each and D2 was 3.29 and D3 was 0,00. Luckily I tried to check without changing the sketch the D4 pin which had a voltage this time of 3.27 . What am I supposed to believe and debug for this? Any suggestions?

Cheers

P.S. D1 pin worked as expected
P.S.2 I suppose one has to set to low all output pins in AppStart to save some power.

 

[hatzisn]

I tried setting alternatively D1, D2, D3, D4 to high and all other 3 pins to low. And it worked as expected. What can I make out from both this behaviour and the previous?

 

[Mark Read]

Firstly you do not say how you are powering the Wemos and secondly, what are you doing with the voltmeter anyway??? Why is the voltage so important to you?

 

[hatzisn]

I am powering it with USB. It was the first time I soldered the pins of a board and I wanted to make sure that everything was soldered correctly and works as expected (it didn't) - thus the measuring of the voltage of the pins.

 

[Mark Read]

Just measuring the voltage on the pins is not really the best way to check your soldering. It would be easier to use an LED and a resisitor. Set all digital outputs to high and test each one with a jumper wire to the LED. Then do the same with Low, nothing should work! If all outputs work on high and not on low, you have soldered correctly.