I've been (gradually!!!) building a "barn door star tracker" in bits n pieces over I guess nearly the last year. For those who are interested it's a gadget for doing long exposure astrophotography, by taking out the rotation of the earth - imagine something like these but in my case a bit bigger and more wooden!
The structure is now pretty much done and I've tested the basic Arduino code which drives the 5v 28BYJ48 stepper motor (I am using a pro micro) to move the camera part. So far so good!
However, when I've been testing, the power comes from the USB for the Arduino, and from my bench power supply for the stepper (via ULN2003 driver board).
Now I need to figure out how to power this in the field (well, the garden to be honest!), and this is where I am stuck.
Can anyone recommend a decent battery setup that will let me run both Arduino and stepper at the same time?
I have some phone charger battery packs.
Cheap on aliexpress and you supply your own 18650 set of batteries.
I have not run any steppers, but it works for LCD displays.
Thanks both, some good options there! Once I’ve got the battery, do I need some kind of power supply board for each bit (Arduino and stepper), or is it possible to power them off the same +5v rail?
This one has two outputs.
as a note the solar is worthless. the 'charging' LED uses 80% of the charge. someone calculated that it would take 30 days to charge if left in full sun in the summer.
as a battery bank, it outputs around 5 volts for my NANO
You can have one battery pack supplying power to a power supply and distributions center or board. I'd have a regulator for all non-motor stuff and a regulator(s) for the motor(s). I'd filter the motors with a larger output electrolytic cap then the component regulator.
OK, after doing a bit more investigation, is something like the attached diagram feasible?
The idea is to use a couple of these LM2596 boards, one supplying the Arduino @ 7V, the other supplying the stepper driver board at 5V, both powered from the same battery.
Please ignore the picture of a 9V battery, the idea would be to use a LIPO battery like this as suggested by Idahowalker above.
Since you have a 5v regulator for the motors, there is no point in feeding the Arduino with 7v, it wants 5v too. You are using three regulators where one should suffice.
Nick_Pyner:
Since you have a 5v regulator for the motors, there is no point in feeding the Arduino with 7v, it wants 5v too. You are using three regulators where one should suffice.
Thanks, make sense - then from what I have read, I believe should send the regulated 5V input for to the VCC pin instead of RAW.
One question though: don't I still need separate regulators for the stepper driver board and the Arduino?
Brutha:
One question though: don't I still need separate regulators for the stepper driver board and the Arduino?
I think it is going to be a matter that is at the discretion of the hobbyist's.
Myself, I'd give the 'motor' its own regulated power supply. To me, having another regulator to run the noisy motor parts provides some degree of separation. My 2 smoked ESP32's and one smoked ESP32 WROVER were all on a single regulator shared with a 'motor.'
Brutha:
Thanks, make sense - then from what I have read, I believe should send the regulated 5V input for to the VCC pin instead of RAW.
The datasheet should tell you, and you are probably right. It is called VIN on Uno etc., but it looks like you are using a Nano and I'm not familiar with them.
I think Idahowalker has a point, it sounds like the voice of experience, and it may well be easier and cheaper than ensuring a single supply has sufficiently clean output.
Idahowalker:
Oh, have you figured out the battery charging electronics?
Hi, was this addressed to me? If so, no I haven't - have I done a confusing diagram?
BTW, just so I understand properly: you are suggesting I use two regulators as I've shown, one feeding the Arduino (via the direct voltage input rather than a regulated input), and another for the motor, right?
Brutha:
Hi, was this addressed to me? If so, no I haven't - have I done a confusing diagram?
BTW, just so I understand properly: you are suggesting I use two regulators as I've shown, one feeding the Arduino (via the direct voltage input rather than a regulated input), and another for the motor, right?
Yes, I was 'talking' to you about recharging the battery. Diagram is not confusing.
Yes, 2 5V regulators, onto to the Arduino and the other to supply the motor. Of course, just sending the battery voltage to the Arduino and letting its regulator do its thing works to.
Idahowalker:
Yes, I was 'talking' to you about recharging the battery. Diagram is not confusing.
Yes, 2 5V regulators, onto to the Arduino and the other to supply the motor. Of course, just sending the battery voltage to the Arduino and letting its regulator do its thing works to.
