Why The Pro Micro Is Perfect For Embedded Arduino Projects

Like most people, I started with an Arduino Uno but was quite hesitant to try different Arduino form factors, especially the smaller ones.

I was unsure whether I had to do anything special to make them work, if they had any limitations, and whether they were a bit dodgy/a scam.

However, I’m happy to say that after taking the jump and buying my first Pro Micro, I have become a massive fan and use them in the majority of my electronics projects.

In this article, I’d like to tell you why the Pro Micro is so good, and to answer some questions you may have if you’ve never used one before. Oh, BTW, I am not gaining anything from Pro Micro sales in any way, I just really bloody love them and think you might do too!

Here’s what the Pro Micro looks like:

Without further ado, let’s get stuck in…

Reason 1) It can do everything an Uno can

Yep, if you’re worried about functionality I can confirm that the Pro Micro can do everything the Uno can. Any code you write for an Arduino Uno will work perfectly on the Pro Micro (and any other Arduino for that matter).

This is because the Pro Micro is electrically identical to an Arduino Leonardo –  if you’ve not come across it, the Arduino Leonardo is a ‘sister’ board to the Arduino Uno – they’re both very similar and for 95% of applications they can be used interchangeably. Here’s what the Leonardo looks like…

The Pro Micro uses the same microchip and has the same functionality as the Leonardo… it even appears as ‘Arduino Leonardo’ in the Arduino IDE! The only difference really is that it’s significantly smaller.

Reason 2) It’s super cheap

Oh boy, it’s so cheap! You can pick up Arduino-compatible Pro Micros from Ebay for under £4. Because of the low price, you can solder a Pro Micro into your project and not worry about breaking the bank.

Although I was initially worried about buying cheap Pro Micros on Ebay, I have not been disappointed yet. They all tend to come from China which means it may take 2 weeks to arrive, but the quality is always perfectly good. I tend to buy five of them at a time and that sets me up for a couple of months.

Sidenote: As the ones on Ebay are clones, none of the money from their sale actually supports the people behind Arduino, so if you like, you can donate to Arduino at www.arduino.cc/en/Main/Donate.

Reason 3) It’s compact and breadboard friendly

The Pro Micro comes with pin headers which you solder on. They’re the right spacing to fit into a breadboard so you can just plug it in and start prototyping – no messy hookup wires!

Another great thing is that the Pro Micro can be plugged in directly via USB and programmed from the Arduino IDE, just like you would with an Arduino Uno. This means you can put it in your breadboard and then update the code as much as you like whilst tinkering with the surrounding circuitry.

It makes for rapid, fun and easy prototyping – just what we want! As a bonus, the USB connection can also be used to power everything on the breadboard so you don’t need to worry about batteries or power supplies.

Just use the VCC and GND pins on the Pro Micro for power – so long as you draw no more than 200 mA you’ll be fine – this should be plenty to power LEDs, buzzers and other chips. However, if you want to use motors or other higher current components, you will need a separate power supply.

Reason 4) You can embed it

Due to the small size, low cost and easy programming, you can happily embed a Pro Micro into your project and leave it there. I actually did just this in a Kickstarter campaign I launched for a Pro Micro-powered USB keypad.

I built a circuit board around the Pro Micro and used little black 3D prints to hold it in place (it’s upside down – this was intentional, I promise!).

The circuit board with the Pro Micro soldered on then had a load of keyboard keys added and was screwed into a case. Finally, I added colourful keycaps.

So as you can see, the Pro Micro works perfectly well when embedded within a project. I actually sold a couple of these keypads so I know that somewhere, someone is using a Pro Micro to control their computer!

Reason 5) It can act as a keyboard and a mouse

The Pro Micro’s party trick is that you can programme it to act as a keyboard or a mouse (or both at the same time)… which explains the USB keypad in the previous section.

Therefore, you can use it to control your computer! Here is me playing the addictive game Helicopter with a Pro Micro. Every time I push the button, the Pro Micro does a left click on my computer, causing the helicopter to fly.


If you’re interested in using your Pro Micro as a keyboard or mouse, Sparkfun have a really good tutorial to get you started, which you can find here.

Pro Micro Top Tips:

  • When programming the Pro Micro, it will show up as ‘Arduino Leonardo’ in the Arduino IDE and when selecting the type of board, you also need to select Leonardo.
  • There are two versions which you can buy – a 5V, 16 MHz version and a 3.3V, 8 MHz version. Unless you have a really good reason, I would always go for the 5V one.
  • Don’t get confused with the Pro Mini. a lot of people online confuse the Pro Micro (which has a USB connector) with the Pro Mini (doesn’t have a USB connector). Note the difference in the pictures below. When buying one, make sure to get a Pro Micro.

Wrapping Up

As you can tell I am a massive fan of the Pro Micro and think the combination of small size, low cost and simple programming make it a fantastic little board for hobbyists.

If you’ve got any thoughts on this I’d be delighted to hear them in the comments. If there is anything else you’d like to know about the Pro Micro, don’t hesitate to ask!

Bye for now,


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