12v to 5v divider

Hi,

I’m considering powering my next Arduino project with a DC power supply. I need to power:

  1. Arduino UNO, approximately drawing 30 milliamperes (5 volts).
  2. Oled connected to the Arduino, approximately drawing 30 milliamperes (5 volts).
  3. Solenoid, approximately drawing up to 2 amperes (12 volts).

In my thinking, I need some sort of a power supply that will give me both 12 and 5 volts and it must be able to provide me with say 3 amperes.

My question to someone who has the knowledge is:
Would it be possible to use a 12 volts 7 amperes DC power supply in conjunction with a switching regulator. That way being able to supply the 12 volts and enough amperes to the solenoid as well as providing the 5 volts and enough amperes to the Arduino?

These are the products I’ve been looking at for the purpose:
12 volts power supply
Switching regulator down to 5 volts

Your time and knowledge is very much appreciated.

ebay- 12v to usb 5v 2A

I’ve butchered one of these in the past to use for a project (12v controlling solenoids and 5v for relays). Cut the far end off the USB cable and you have two wires with a steady 5v (2A). There may be a more elegant solution, but i had one of these laying around so utilised that.

Hi, thank you for sharing your knowledge. I’m not following completely. Do you suggest that I use the 12v power supply that I suggested? How do you mean that I could make use of a USB cable in conjuction with that? I know that the usb provide 5 volts via the output of my computer, howevee I want to to use my wall outlet and provide enough volts and amps using only one connection (from the wall output).

Thanks again.

Just a 12v power supply in combination with a simple 7805 lineair regulator should suffice (including the proper capacitors of course) Buck converters are more efficient, but for 60mA i doubt if it matters much. for that sort of current even a TO-92 package would be ok, but i’d just use a TO-220 package in case the 5v requirements increase.

It depends upon of board and the power you are goiving. Which board you are using to do the same?

If your current estimates are accurate and you only need 60mA at 5V, why not just use the onboard 5V regulator on your Arduino Uno by connecting your 12V power supply to the DC jack input? The built-in NCP1117ST50T3G regulator is rated for 1A, so 60mA should not stress it at all.

This is roughly what I meant I’ve done in the past if the source is 12V DC. it’s not pretty but it works, especially if you’ve got one of these car converters laying around. it will draw more current in the converter circuitry than a linear regulator.

The arduino will use 5v over USB, if your supplying power to the external barrel jack though I believe it is 7v that is recommended in the datasheet with 6v as a minimum supply voltage

The recommended voltage through the DC jack socket is 7V - 12V. I have used 12V successfully with no problems - here is a quote taken from the Tech Specs section of the Arduino Uno webpage:

Input Voltage (recommended) 7-12V
Input Voltage (limit) 6-20V