Hi, I am a hobby type, writing my own software to control my astronomical observatory. It's all battery powered as there's no ac mains on site.

My current problem is that I have a microcontroller (Arduino Mega2560 board in this case) which controls a stepper motor via an MA860H stepper controller, to open and close a door. If powered by DC the MA860H requires a minimum of 24 Volts and I supply this via two 8AH lead acid batteries wired in series. The Arduno board is currently powered separately via another 12v PSU which has a 'cigar lighter' type connector into which I plug a USB adapter. From that a USB cable is plugged to the Arduino. It all works fine.

The MA860H spec is here

So my query is that I'd like to do away with the separate Arduino PSU and instead connect to one of the two 12V batteries which power the stepper controller (still using the USB adapter to get the 5v). My concern is that there might be noise on the power line from the stepper/ driver and that might affect the Arduino, making it unstable.

Unfortunately I do not have an oscilloscope with which to check.

Any help with this idea much appreciated,
Paul

 

A voltage regulator shouldn't have problems generating 5V from a 12V battery that's clean enough for the Arduino. If you find that you have issues, you can increase the size of the capacitors on the input and/or output of the regulator. If you continue to have issues, you can try adding a choke filter.

https://en.wikipedia.org/wiki/Ferrite_bead

 

You are engaging in premature optimization. You don’t even know if there is a problem. If there is, you won’t know the nature of it until is happens. You don’t have a scope, but you can test the running system and see if it glitches or otherwise misbehaves.

 

You are engaging in premature optimization. You don’t even know if there is a problem. If there is, you won’t know the nature of it until is happens. You don’t have a scope, but you can test the running system and see if it glitches or otherwise misbehaves.

Yes, I guess I am, but rather than destroy the Arduino, I thought I'd ask first

 

A voltage regulator shouldn't have problems generating 5V from a 12V battery that's clean enough for the Arduino. If you find that you have issues, you can increase the size of the capacitors on the input and/or output of the regulator. If you continue to have issues, you can try adding a choke filter.

https://en.wikipedia.org/wiki/Ferrite_bead

Thanks for the info, I guess I'm not going to destroy the Arduino then, so I'll give it a try.

 

If you use the same battery for the motors and the microcontroller, make sure that the common (-) return is wired individually for each right back to the battery negative terminal. That will eliminate the possibility of the motor current causing unwanted voltage surges on the microcontroller supply return wiring.

 

Have you checked the freely available Arduino board schematic? Does it already have bypass cap(s)? It has an on-board voltage regulator, right? (I forget.) Check the specs on what input voltages it will accept.

 

Hantek 6022 runs off laptop, called a USB oscilloscope. It appears to be basic off grid concerns about noise on sensitive equipment.
A USB scope can help locate noise help mitigating noise with capacitor filter. Step up converter, (*voltage regulator circuit very important*) analog
filter board, effective faraday shielding, grounding. It is equipment in a system that is ideal for off grid astronomy which is at the heart of an ongoing software control development.

 

You neglected to state how the 2- 12-Volt Batteries are being charged, or what type of Batteries they are.

Connecting a Load to just one of the 2 Batteries will result in
differing states of Charge between the 2 Batteries,
this could result in unwanted problems with Charging,
and there is a possibility of eventually causing damage to one of the Batteries.

How are You Charging your Batteries ?

There are 36-Volt USB Power-Supplies readily available ........
https://www.amazon.com/UCTRONICS-Co...1_3?keywords=24v+to+usb&qid=1649889171&sr=8-3
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