Hi all am new to arduino nano's, I am building a 3d printed ball clock and hope someone can help. I cannot run the electronics as per diagram. if I connect the live wire from the 12v to the vin it bricks my nano, it will only work if I disconnect the live and connect a usb feed to the nano then it will work, will I have to use 2 feeds to run it?. I cannot upload the diagram that came with the 3d files due to been a newbie, it consists of an ardino nano, a drv8825 and a nema 17, thanks for any help 
Welcome to the forum
I see no diagram
What happens if you disconnect ALL other connections to the Nano?
forgot to remove the as per diagram cos if you read further along I cannot upload diagram due to been a newbie.
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@Paul_KD7HB not tried it with all others disconnected as have bricked about 5 nano's have ordered some more as am on my last one.
Esquema_electrĂłnico.pdf (652.0 KB)
this is the diagram.
Thank you for the schematic. I also see documentation to the effect: "There is a voltage regulator on board so it can accept voltage up to 12VDC.".. Does you 12 volts exceed 12 VDC at any time? Perhaps when you are using the motor?
This should not damage your a Nano, if your diagram is accurate.
Please post bright, clear photos so we can see every connection.
Measure the 12V supply. Is it truly 12V?
Have measured the voltage and it is 12v, when i connect the 12v to arduino I get 5v out of vcc, I connected an old nano and the tx,rx andpower lights stay lit but no movement on motor.
Welcome! It is doing exactly what I would expect, the Arduino is not a power supply. Use an external supply for the motor. Here is something you would have found months ago had you looked in this forum:
il's Crispy Critter Rules, they apply to processor hardware:
Rule #1. A Power Supply the Arduino is NOT!
Rule #2. Never Connect Anything Inductive to an Arduino!
Rule #3 Don't connecting or disconnecting wires with power on.
Rule #4 Do not apply power to any pin unless you know what you are doing.
LaryD's Corollary's
Coro #1 when first starting out, add a 220R resistor in series with both Input and Output pins.
Coro #2 buy a DMM (Digital Multi-meter) to measure voltages, currents and resistance.
Violating these rules tends to make crispy critters out of Arduinos.
Hint: It is best to keep the wires under 25cm/10" for good performance.
If you are lucky you may have only fried the regulator and they could be repaired if you have the needed skill set in your toolbox. I do not know but the Pro Mini is a different board then the Nano which has many varieties and processors.
Did you look at the schematic? Power supply is 12V. 5V is only used to keep reset and sleep pins at a certain level, not to power the module.
Sorry I did not see it.
What is missing is the big capacitor directly between Vmot and Gnd of the DRV8825. This capacitor is mandatory, because the Vmot is not only a current sink, but also a current source when the DRV8825 is working. The capacitor must buffer these current peaks.
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Just like to say I am really impressed on the help and response from this forum, @MicroBahner I saw a post here UPDATE: Current adjustment for motor drivers (DRV8825 / A4988) - #2 by Southpark that uses a 100uf capacitor is this what you mean?
Yes, that's it.
Just ordered some will let you know the outcome in a day or two.
when you say "bricked" what symptoms are showing?
I would:
- Disconnect all the external connections.
- Using the USB input, load and the "Blinkwithoutdelay" example from Files/examples/digital
See if the board LED blinks. You may have only fried the 12V to 5V regulator.
@JohnRob have tried what you suggested and 2 of the nano's say usb not recognised and have 3 red lights, the other 2 have 3 red lights but the port is not recognised,
@MicroBahner soldered the capacitor to the plus and negative of the 12v supply and WORKS perfectly, many thanks to you and all for replies and suggestions.
Glad I could help. But it would be better to solder it directly at or very near to the DRV8825 board.