# Common power source **URL:** \ **Category:** Motors, Mechanics, Power and CNC\ **Created:** [March 9, 2024, 5:18pm UTC](https://forum.arduino.cc/t/common-power-source/1233551 "2024-03-09T17:18:58Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![majkelowsky99](https://avatars.discourse-cdn.com/v4/letter/m/e274bd/32.png) [@majkelowsky99](https://forum.arduino.cc/u/majkelowsky99)\ **Post date:** [March 9, 2024, 5:18pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/1 "2024-03-09T17:18:58Z")
Hi, I would like to power Arduino, R385 water pump and stepper motor with common power source 12V. To lower voltage I would like to use LM2596. I,ve made a wiring diagram and would like to know If I connect everything correctly. ![water pump, stepper motor wiring](https://europe1.discourse-cdn.com/arduino/original/4X/3/a/5/3a5abe15e52c7ceaf57c71dd7538b89eac838a79.png) ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [March 9, 2024, 5:28pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/2 "2024-03-09T17:28:30Z")
You must be **very very** careful when connecting an adjustable Buck converter to the 5V output pin on an UNO. If the voltage is to high or not well regulated, you will burn out the UNO. If the voltage is too low you could also damage the Uno If you accidently connect something to Vin you could again damage the Uno. ---
**Author:** ![majkelowsky99](https://avatars.discourse-cdn.com/v4/letter/m/e274bd/32.png) [@majkelowsky99](https://forum.arduino.cc/u/majkelowsky99)\ **Post date:** [March 9, 2024, 5:39pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/3 "2024-03-09T17:39:42Z")
Apart from the fact that I have to be very careful. I would like to know if wiring diagram is correct. ---
**Author:** ![johnerrington](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/johnerrington/32/340106_2.png) [@johnerrington](https://forum.arduino.cc/u/johnerrington)\ **Post date:** [March 9, 2024, 5:43pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/4 "2024-03-09T17:43:35Z")
The wiring diagram LOOKS fine - but it would depend on the actual devices you are using and their current demands. SO could you provide links? ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [March 9, 2024, 5:47pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/5 "2024-03-09T17:47:22Z")
> [@majkelowsky99](#): > > Apart from the fact that I have to be very careful. I would like to know if wiring diagram is correct. Not quite, the pump needs a power source Is that relay 5V or 12V? ---
**Author:** ![majkelowsky99](https://avatars.discourse-cdn.com/v4/letter/m/e274bd/32.png) [@majkelowsky99](https://forum.arduino.cc/u/majkelowsky99)\ **Post date:** [March 9, 2024, 5:58pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/6 "2024-03-09T17:58:20Z")
12v relay and water pump will be powered directly from 12v ---
**Author:** ![mancera1979](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/mancera1979/32/732001_2.png) [@mancera1979](https://forum.arduino.cc/u/mancera1979)\ **Post date:** [March 9, 2024, 5:59pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/7 "2024-03-09T17:59:40Z")
Your diagram does not show how power will get to the pump. Also, it shows a 5V relay. Be sure to use a 12V relay. ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [March 9, 2024, 6:01pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/8 "2024-03-09T18:01:36Z")
> [@majkelowsky99](#): > > 12v relay Are you sure that your 12V relay can be controlled by an UNO 5V output? ---
**Author:** ![majkelowsky99](https://avatars.discourse-cdn.com/v4/letter/m/e274bd/32.png) [@majkelowsky99](https://forum.arduino.cc/u/majkelowsky99)\ **Post date:** [March 9, 2024, 6:04pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/9 "2024-03-09T18:04:09Z")
Water pump:[https://robu.in/product/dc6-12v-mini-aquarium-water-pump-r385/](https://robu.in/product/dc6-12v-mini-aquarium-water-pump-r385/) Stepper motor :[Stepper motor 28BYJ-48 5V / 0.1A / 0.03Nm with Botland - Robotic Shop](https://botland.store/stepper-motors/12807-stepper-motor-28byj-48-5v-01a-003nm-with-uln2003-controller-5904422306410.html) Water pump - 0,5A - 0,7A Stepper motor - 100mA ---
**Author:** ![majkelowsky99](https://avatars.discourse-cdn.com/v4/letter/m/e274bd/32.png) [@majkelowsky99](https://forum.arduino.cc/u/majkelowsky99)\ **Post date:** [March 9, 2024, 6:14pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/10 "2024-03-09T18:14:14Z")
My wiring diagram may be unreadable a little bit. On the left side, there is a barrel jack connector for 12v 2a charger. And I wanted to power relay directly from charger. ---
**Author:** ![majkelowsky99](https://avatars.discourse-cdn.com/v4/letter/m/e274bd/32.png) [@majkelowsky99](https://forum.arduino.cc/u/majkelowsky99)\ **Post date:** [March 9, 2024, 6:15pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/11 "2024-03-09T18:15:11Z")
On the left, there is barrel jack connector for 12v charger and I wanted to power water pump directly from charger. ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [March 9, 2024, 6:18pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/12 "2024-03-09T18:18:30Z")
> [@majkelowsky99](#): > > And I wanted to power relay directly from charger. If it a 12V relay that is OK but is is safe to control it with a 5V digital signal? ---
**Author:** ![LarryD](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/larryd/32/215550_2.png) [@LarryD](https://forum.arduino.cc/u/LarryD)\ **Post date:** [March 9, 2024, 6:22pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/13 "2024-03-09T18:22:02Z")
**Always** show us good images of **your** ‘actual’ wiring. Give links to components. - We need to see the actual relay module, give us a link. 5v logic to the relay module IN pin cannot control a 12v relay through the input opto isolator. Need more information 🥺 . ---
**Author:** ![mancera1979](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/mancera1979/32/732001_2.png) [@mancera1979](https://forum.arduino.cc/u/mancera1979)\ **Post date:** [March 9, 2024, 6:29pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/14 "2024-03-09T18:29:40Z")
To control the pump with the relay you need to connect it in series with the pump. You can connect the power supply black wire to the pump, and the red wire to the central relay terminal. From the other relay terminal (NO), run a wire to the other pump terminal. You need 3 wires, not 2. In the relay, NO stands for Normally Open, NC for Normally Closed. "Normally" means "when the relay is not energized it is". A source of concern is that the pump motor can induce noise into the buck converter and cause the Arduino to fail. You may have to add a capacitor in parallel with the pump. Try with 100µF @ 16V. > [@jim-p](#): > > If the voltage is to high or not well regulated, you will burn out the UNO. This is important. If the stepper side can handle 7.5V, configure the buck converter accordingly and connect it to Vin. ---
**Author:** ![majkelowsky99](https://avatars.discourse-cdn.com/v4/letter/m/e274bd/32.png) [@majkelowsky99](https://forum.arduino.cc/u/majkelowsky99)\ **Post date:** [March 9, 2024, 7:45pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/15 "2024-03-09T19:45:30Z")
Thank you guys for all advices. ---
**Author:** ![gilshultz](https://avatars.discourse-cdn.com/v4/letter/g/67e7ee/32.png) [@gilshultz](https://forum.arduino.cc/u/gilshultz)\ **Post date:** [March 10, 2024, 2:18am UTC](https://forum.arduino.cc/t/common-power-source/1233551/16 "2024-03-10T02:18:15Z")
When adjusting the regulators, do it before connecting any parts to it. ---
**Author:** ![LarryD](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/larryd/32/215550_2.png) [@LarryD](https://forum.arduino.cc/u/LarryD)\ **Post date:** [March 10, 2024, 2:53am UTC](https://forum.arduino.cc/t/common-power-source/1233551/17 "2024-03-10T02:53:25Z")
> [@gilshultz](#): > > do it before connecting any parts to it - Or add a resistor to draw 500mA. - Adjust voltage. - Add finger nail polish to the screw on potentiometer. ---
**Author:** ![majkelowsky99](https://avatars.discourse-cdn.com/v4/letter/m/e274bd/32.png) [@majkelowsky99](https://forum.arduino.cc/u/majkelowsky99)\ **Post date:** [March 10, 2024, 3:27pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/18 "2024-03-10T15:27:42Z")
Is there a chance or a way to control 12v relay through 5v signal? ---
**Author:** ![LarryD](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/larryd/32/215550_2.png) [@LarryD](https://forum.arduino.cc/u/LarryD)\ **Post date:** [March 10, 2024, 3:45pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/19 "2024-03-10T15:45:08Z")
**Always** show us good images of **your** ‘actual’ wiring. Please, give links to components including the relay module. - We need to see the actual **relay module, give us a link**. 5v logic to the relay module IN pin cannot control a 12v relay through the input opto isolator. Need more information 🥺 . Note: if the module is driving the relay coil with a transistor only, 5v can key the transistor and the 12v relay will energize. Please link us to the relay. ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [March 10, 2024, 3:58pm UTC](https://forum.arduino.cc/t/common-power-source/1233551/20 "2024-03-10T15:58:18Z")
> [@majkelowsky99](#): > > Is there a chance or a way to control 12v relay through 5v signal? Yes, you can use a simple one transistor circuit. How much current does the relay coil need? [Next page](https://forum.arduino.cc/t/common-power-source/1233551.md?page=2)