I'm sure this has been asked but I can't seem to find it; how do I power both an arduino nano and a ULN2003 driver (and stepper) from the same 12V power source? I put together a basic circuit (below), but it only works when powered through the USB, not the 12V plug. Any advice on where I'm going wrong?
You don't appear to have the uln2003 Gnd connected to the barrel jack Gnd.
Or maybe you do; I can't tell what the 2nd pin up is connected to, some unnamed pin on the Nano.
Connect the switch wiring to diagonal pins. I think as drawn the two pins on each will be connected all the time.
You can confirm with a multimeter.
Your graphic indicates the 12 V ground is connected to the ULN2003 board and the Arduino Nano.
Powering a Nano from 12 V - and using the "Vin" pin in general - is a bad idea because the regulator on many clones at least is reported not to cope with 12 V. And even if it can, it cannot cope with additional devices you may wish to connect to the "5V" pin as it will overheat and shut down.
We would like to see the Web links to the stepper and its control board you are using.
Paul__B:
We would like to see the Web links to the stepper and its control board you are using.
Unfortunately I don't have a lot of information on the stepper/board; it came from an amazon kit I had laying around The board says "2PH78500A" if that helps. Also the nano is for sure a cheap clone.
How would you recommend I power this? I'd like to keep it as simple as possible so that I can fit everything in a tight space.
Also, just FYI, this is for an electronic focuser on a telescope; the idea is to control the focus with buttons so that I can dial it in for astrophotography. It works great when plugged in via the USB port, but I'd hate to just give up and go that route rather than actually learn the proper way to do it!
CrossRoads:
You don't appear to have the uln2003 Gnd connected to the barrel jack Gnd.
Or maybe you do; I can't tell what the 2nd pin up is connected to, some unnamed pin on the Nano.
Sorry, I covered that with a wire! That's the 5V pin on the arduino going to the ULN2003, with the other wire going to the ground on the plug. My intent was to power the Nano with 12V, then use the 5V pin to power the stepper... but maybe that's a bad idea?
tommyent:
My intent was to power the Nano with 12V, then use the 5V pin to power the stepper... but maybe that's a bad idea?
Very bad idea!
The Nano actually runs on 5 V; the regulator is as I explained, pretty useless so just forget about "Vin".
This is the "standard" 5 V stepper module apparently,
Aliexpress link
It will probably do for your purpose. Power it all with a USB "Phone charger" of at least 1 Amp rating which you can connect to the USB port, but since the ULN2003 is very inappropriate for 5 V devices as it already loses at least 1.2 V and the Nano loses about 0.6 V in the series diode between USB and "5V", it might be better to connect the "charger" directly to the "5V" pin and stepper driver.
Hi,
Can you draw ,pen(cil) and paper, your circuit diagram please, with labels.
Fritzy as you have found is very confusing and "wiring" covers a lot of "detail".
Thanks.. Tom...
If you have indeed a 28BYJ-48 stepper, check whether it's a 5V or 12V version. Operating the 5V one at 12V will likely result in smoke...
If it works from USB, I'm guessing it's powered from the 5V pin of the Arduino. Works indeed when the Arduino gets powered by USB, will cause near instant overheating of the regulator if you try the same when powering the Nano off 12V.
wvmarle:
If you have indeed a 28BYJ-48 stepper, check whether it's a 5V or 12V version.
Noticed that. Obviously the 12 V version is better suited to the ULN2003.
I have one - or is it two? Purchased way back when I first struck Arduino in 2013, haven't actually played with it since. Have a mind to buy some more "just for the heck of it" (after all, people waste money on far more insubstantial pursuits, at least I am not "mathematically challenged" as a gambler ) with the (possible) intention of finding actual uses for them!
Most uses require a "zero sensor".
Aliexpress link
Here's an interesting thought.
There is a ton of these things on Aliexpress and less favourably, eBay. I can believe that the board was cooked up as a module in the same way as all the others that form part of the Arduino and others "kit" cosmos, but what was the original purpose of these "28BYJ-48" geared steppers?
Paul__B:
Here's an interesting thought.There is a ton of these things on Aliexpress and less favourably, eBay. I can believe that the board was cooked up as a module in the same way as all the others that form part of the Arduino and others "kit" cosmos, but what was the original purpose of these "28BYJ-48" geared steppers?
As louver sweep motors in AC systems.
As actuators in bench top ice making machines.
Tom...
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