Pro Micro (5V, 16Mhz) - Need a few clarifications about pins

Hi, I've been getting into Arduino with my daughter and I'm looking to build a real project with her. Building a USB Dual Analog Gamepad sounds like fun, but I could really use a few clarifications. To start I'll outline the basics of what I'm trying to do for clarity.

Make a PS/Xbox style HID USB gamepad for use with a PC (or Raspberry Pi, etc): -4x face buttons (A,B,X,Y) -4x shoulder buttons (L1, L2, R1, R2) -2x 'utility' buttons (Select & Start) -4x button based DPAD (Up, Down, Left, Right) -2x dual axis Analog Joysticks FWIW, I'm not doing any fancy custom PCB, just THT perf board and wires for everything.

So after looking through the options the Pro Micro (5V, 16Mhz) seems like exactly what I need. It does USB communication with a PC already, and can be setup to show up as a HID Game Controller. Plus there's a good Joystick library for Leonardo/Pro Micro boards that'll make life a lot easier. I do have a few questions about the Pro Micro though.

-Does it need pins 0&1 (Tx, Rx) for USB serial communication or can I use them for button inputs? I need 14 digital pins for my buttons, and honestly I'd prefer not to use shift registers if I can avoid it (one less thing taking up space and requiring wiring/soldering time).

-It says there are two 'extra' digital pins underneath the USB send & receive LEDs. If I want to use these do I need to de-solder the LEDs first?

-Is the RAW pin ok to power things with? The board itself will always be powered by USB. The two analog sticks I picked up need two +5V wires each, and there's only one VCC pin. It'd be a little cleaner to have two wires coming from each hole (RAW and VCC) than having some more jumpers/splices. Not really a big deal, if it isn't safe to power things from RAW I'm fine with having jumper wires instead of burning things out.

Any other tips/info about making a gamepad are definitely welcome. I did my best to do my research but it never hurts to have more info.


1 No, pins 0 and 1 are only needed for USB serial on devices that don't have native USB.

  1. If you're out of pins, get a micro, instead of a pro micro. Pro micro is a gimped version of micro without all the pins broken out - I don't know why they are so abundant. If you need to use an I/O pin otherwise connected to an LED, if the pin is an output driving something that doesn't draw much current, you don't need to remove the LED. If using it as an input, though, you do need to remove the LED.

  2. No, you may not use RAW to power things - it's the input to the on-board regulator. Either make a Y-cable or use a little scrap of prototyping board to split it up (hey, guess what, I happen to sell some lovely little pieces of prototyping board).

Thanks for clearing things up DrAzzy. I'll keep the tip about the Micro in mind when I decide to build a second game pad (I already have the pro micro coming). Kinda odd naming convention, I incorrectly assumed 'pro' meant it was the same thing just missing a few 'convenience' things for the sake of being slightly smaller.

If you consider some of the digital I/O pins "convenience", then yes, that's true....

Pro Micros have a bad reputation when it comes to the USB connector; it easily breaks off.

I think it's advisable to use a panel mount connector with a cable that fits in the Pro Micro; look at the images that google gives for micro usb panel mount to get ideas.