Seeeduino 4.2 Low output voltage

My seeeduino 4.2 output pins only output 3.5 volts with an open-circuit load. I verified this after it failed to turn on a SS relay with 5v input. I disconnected the relay from the output, thinking maybe it pulls too much current. Nope, 3.5 volts open.

I thought connecting a 12v source would fix this, but it didn’t. Anything else I can do? I probably don’t need exactly 5 volts out, but it should be close. My application needs to switch frequently, so a mechanical relay is a poor substitute.

Hi @phatgeek
Did you slide the slide selector switch on seeeduino V4.2 from 3.3v to 5v?
I followed this wiki did a similar test, the seeeduino V4.2 can output 5v.

Hi. Thanks. Yes, the selector switch is set to 5v. I don’t have any sensors connected, so no need for 3.3v.

I do have two analog inputs with 10k potentiometers attached. That should pull 0.2 milliamps, so I think shouldn’t be pulling the voltage down. I tried output on other pins and found a maximum of 3.7v on pin 8. Other pins are even lower, and even pin 8 is unable to drive my relay.

Hi @phatgeek
Maybe due to you used two analog inputs with 10k potentiometers attached that pulling the voltage down.
You can try to not use potentiometers to do a test, so you can know whether the board can output 5V.

Hi, Jiachenglu.

Thank you. I disconnected my Seeduino from my circuit and you must be right. I’m surprised, but it looks like 5000k ohms is too much of a load. When the pots are disconnected I get 5v. I’ll replace them with 500k pots and hopefully that solves my problem! Thanks again!