OSOYOO Pro Micro 5V/16MHz Module Board with 2 Row pin Header Replace wit Pro Mini for Arduino

Basic, small controller, works as it should without any real issues. About half the size of a standard lighter, allows it to be mounted in very small places. Mine was used for a custom Clone Hero guitar build, and worked great.

Making a jog dongle for my CNC, only need 10 keys and this board will handle that easily. My issue is I spent a full day trying to get it to connect to the Arduino app, first few hours to track down the driver I needed (no documents in the box and I am new to this) I finally got that working thanks to SparkFun's site.But with the correct drivers it still would not connect. I knew that some cables are power only so I tried 3 different ones with no luck (figured something beyond my abilities was set wrong or board was bad) but on day 2 I said what the heck, lets try a third cable and it worked!! No way to tell if a cable has data lines just by looking. Man I lost a bit of hair on that one.I left off 1 star for lack of any documentation. Heck they could have even just stuck a QR code sticker on the box to one of the sites with docs.

Initially, I was having a lot of trouble connecting to my Mac running Mojave. I tried all the instructions here that suggested installing new drivers. Turns out all that was not necessary. The culprit was THE CABLE! After losing an entire weekend day trying to get it to work, I stumbled across a post on an Arduino forum that suggested some micro USB cables are only wired for charging and do not have the data pins connected. None of the micro USB cables I had were working and I realized that yes, they all came into my possession because they were included with other devices for charging purposes. So I found an old box of cables in the garage and found an old Nokia micro USB cable and BAM, now my board was showing up on a port! So, if you're having trouble connecting to a mac, it could be that you are using a cheap cable that may not have data pins connected. Mine works great now and I built a very cool project with it that does exactly what it should. I'm very pleased. :)

So far it works perfectly. Note that I have done a bunch of arduino stuff on my computer before this so I may already have drivers that other people don't have installed.Connected to my computerOpened Arduino IDE and loaded Blink sketchSet board to Leonardo and selected the appropriate COM port (It showed up in the list already identified as a Leonardo)Connected an LED to pin 9 and modified the sketch accordinglyHit upload and within a few seconds I had a blinking LEDNote that for some reason the onboard red Rx LED keeps flashing even after the upload, not sure why. I unplugged it from the computer and connected to the battery pack I used for charging my phone on the go and it started back up with no issues and without the red light blinking. So it does appear to be getting some sort of continuous data signal when plugged into my computer which is odd, but doesn't seem to actually be a problem.The pinout appears to match the sparkfun pro micro board for which I've attached the diagram. EDIT: I just realized that the pins with the white circles around them are the PWM pins.

Board works great. I did not have any difficulties that I could not resolve.Changing my recommendation to use the "Leonardo" board definition. This avoids all problems I had, don't need to download new definition. Only missing 5 pins that are on the Leonardo -- so just don't use those. Also use the macros for RX and TX LED, as pin 13 is one of the missing pins and so is the extra (active high) LED.----------- Original review: -------------That said, I gave 4 stars only due to documentation short comings.This board is electrically a duplicate of the SparkFun Pro Micro - 5V/16MHz, except the RXLED and TXLED (at least on my board) are both red color, and the power LED is green. And the bootloader shows as an Arduino Mini -- which is confusing but works.I use the latest Arduino system on Windows 10, which seemed to then have all driver issues resolved and did not need to download any drivers.I did use the Arduino facility to download the SparkFun board definitions for the "Pro Micro" which has different pin definitions than the recommended Leonardo. (Leonardo should work, but has pin definition problems.)BE ESPECIALLY CAREFUL if you use the "Pro Micro" board setup that when selecting the board type YOU ALSO set the processor selection on a separate menu item to "ATmega32U4 (5V, 16MHz)". Failure to do so will make the board appear to stop working. (Then a complex and tricky sequence of resetting using reset pin and uploading with correct settings within the special 8 second window must be done to reload the board so it will work after the 8 second boot delay elapses.)Other issues are related to and similar to the same issues with the Pro Micro itself, and the Leonardo. This board has the special advantage that the user can feed very fast data through USB, and can simultaneously output data on the RX,TX serial port to another process. I found this especially useful in communicating with a different system using serial data.