Power supply for Arduino and external module

Dear forum members,

I am using:

  • An Arduino mega 2560, which according to this page, should be powered with 7-12V, 500mA-1A.
  • A GSM module which should be powered 4.6-5.2v at 1-2A. Hence, since it draws too many amperes, it cannot be powered from the Arduino 5V pin.

What is the best way to supply power to this system, without using two AC/DC adapters ?

I was for example thinking about using a 9V 3A AC adapter and:

  • Direclty power the Arduino from it.
  • Use a power regulator down to 5V before powering the module.

Is it a good idea ?

Using a high power AC wall adapter sounds like a good idea to me. I would go for a 12V 2A unit since it's easily available everywhere (but that's just my preference).

Try to use a cheap buck converter to get 9V or 12V down to GSM module 5 volts.:)

Update: What's wrong with using 2 different wall adapters?

You can use a switching regulator like LM2575 to give 5 volts to GSM module. It's very energy efficient and will not produce any heat. You can supply 9v to VIN pin of your Arduino.

I am using an LM2575 to power an ATMEGA32A and several other modules like Bluetooth and WiFi modules.

Hi

9V 3A AC adapter

Don't forget you will have to rectify and smooth the rectified AC before you regulate it.

Tom... :)

TomGeorge: Don't forget you will have to rectify and smooth the rectified AC before you regulate it.

Excuse my inexperience, but could you give more details ? If I use a regular AC/DC 9V adapter (say, something that looks like that), do I need to do something before connecting it to a buck converter like that one, to get my 9V down to 5V ?

Hi, If it says its DC output, then no problems, go straight to regulator.

Tom... :)

klaus: Excuse my inexperience, but could you give more details ? If I use a regular AC/DC 9V adapter (say, something that looks like that), do I need to do something before connecting it to a buck converter like that one, to get my 9V down to 5V ?

Nope, you can connect that buck converter directly to your adapter and output will be just fine.:)

He thought you were gonna directly convert AC current without rectification. you should have mentioned DC adapter instead of AC adapter. Or He probably meant that if you use a voltage regulator alone (instead of using a buck converter unit). In that case you need to smooth it using capacitors.

He thought you were gonna directly convert AC current without rectification. you should have mentioned DC adapter instead of AC adapter.

I think the advantage of using the term "wall wart" is it eliminates any confusion that might arise with newbies when using the term "AC/DC adaptor" (which , you would THINK could only mean a device that converts AC to DC !) (and NOT a device that OUTPUTS AC)

raschemmel:
I think the advantage of using the term “wall wart” is it eliminates any confusion that might arise with newbies when using the term “AC/DC adaptor” (which , you would THINK could only mean a device that converts AC to DC !) (and NOT a device that OUTPUTS AC)

True, but in some parts of the world (especially where I live), nobody knows what a wall wart is. Everyone here call it simply “adapter”. Just like the cell phone/ mobile phone/ handy.

Dear forum members,

While it does have a nice formal ring to it, it is not necessary. (you're not writing home to Mom..LOL)

You could just as well have said :

"YO !" "WHUS UP ?"

and while we might be taken aback a little, we would still treat it like any other post.

Thank you very much for your input!