LiPo powered datalogger with 5v analog device

I want to make a LiPo powered datalogger using an MKR Zero, but the analog device I am using requires 5V excitation (between 4.75 and 5.25V).

My understanding of what I have read is that the 5V pin on the Zero works only when it is USB powered or has a Vin of 5V or more, implying that it doesn't work when powered by a 3.7V LiPo battery.

Am I reading this right? To use a 5V device, I'd have to get a separate supply for that.

Or I could just use an Uno (although I like the built-in RTC and SD port of the Zero.)

Any help would be appreciated.

You could add a boost converter to get 5v.

As Larry suggested, use a boost converter. I use the MT3608 a lot on my projects with liPos

Thank you. That looks like a good solution!

Thanks for the tip. That kind of worked.

When I hooked it up, I had a very hard time establishing a serial connection on the micro-USB cable. Hitting the reset button repeatedly during the file upload got it to work sometimes. Is there something I should know about connecting the MT3608 to make it work more easily? Should I put a resistor in the circuit or something like that?

My connections are this:
MKRZero VCC (3.3V) -> MT3608 Vin+ (MT3608 tuned so Vout = 5V)
MT3608 Vout+ -> analog device 5V
Analog device signal -> potentiometer/voltage divider + end
Pot/Voltage divider slider -> MKRZero A1

MT3608 Vin-, Vout-, Analog device GND, Pot - end -> MKRZero GND

Do you see anything that would interfere with the Serial USB connection?


I don’t see anything from my knowledge, can you understand upload a picture of your wiring diagram and how you have it hooked up?
Maybe try uploading a sketch without having the boost converter attached

If I can't have the boost converter, then I cannot use the 3.3V MKR Zero. It's built-in SD and RTC and ability to use an external rechargeable LiPo made it more attractive than an UNO with the rat's nest RTC/SD breakout board.

I think the MPX Ground should be connected to the boost converter ground, but I really do not know. Try creating a new topic with this problem, you might be able to get more help from people that are more advanced

Thanks, but all of the grounds are tied together.

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