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[minushka]

Hi,
I got a basic knowledge about electronic... My question is pretty easy. If I build an astroeq based on arduino. Could I use a 24V power supply on the V+ pin of the DRV8825 boards (only) and use 2 high torque 24V steppers?
Thank you

[TCWORLD]

Hi,

The DRV8825 boards should support doing that. However if you are going to do so, the 78L05 regulator for the 5V rail would have to be replaced with something which supports that input voltage and can provide around 50mA - probably a switching regulator would be needed as a linear would dissipate around 1W which is quite a lot for a small package.

Also, adding an additional 30V zener diode across the 24V supply rail near the motor drivers would be a good idea to keep any voltage spikes to a minimum. Be sure that the capacitors you use on the 24V supply rail are rated for 35V. The ones in the AstroEQ parts list I believe are 25V rated so would not be suitable.

Finally, I would also make sure the current of the motors is not more than say 0.8A/phase (possibly a little higher - maybe 0.9A) as the higher voltage will result in a higher power dissipation on the drivers during switching. As an alternative, you could add additional cooling (heatsink, etc.) to make sure the driver boards don't overheat.

Tom.

[minushka]

Hi Tom,
Thanks for your answer. However I'm not good enough to do that :-). To be sure, Don't you talk about a diy astroeq based on ATMega? Cause I can't found the IC3 component on this schematic (https://www.astroeq.co.uk/doku/lib/exe/fetch.php?media=astroeq_arduino_schematic.pdf)
Anyway, I found good 12V stepper by nanotech. I'm still on the waiting list for the next batch.
Thanks for your time and your project!

[TCWORLD]

That schematic is the one based on the Arduino Mega. If you are going to build that one, you should not connect 24V to the VIN pin of the Arduino as that would fry its regulator.

[minushka]

Allright, I'll try.
Thank you Tom