Wiring & Setting Up the MicroMinim OSD-Airjacker

Wiring & Setting Up the MicroMinim OSD

The MicroMinim OSD is a great bit of kit for any mini quad. It gives you a really configurable on screen display from something as simple as a voltage readout to a full F-16 fighter pilot artificial horizon ladder. And when you are disarmed on the ground you can even tweak your flight controller settings, saving you lugging your laptop the the field.

It's tiny too - about the size of a £1 coin. The trouble is, it has pins and solder pads on all sides so it takes a bit of thought to stop the connections taking up more space that the board itself.

MicroMinim OSD with all pins collected

I found a post on Oscar Liang's blog detailing how he uses double row 90º pin headers and that inspired me to come up with this, even more streamlined take on it.

The only pins I need to access are the six FTDI pins (marked in blue here) and the video in and out pins on the left.

MicroMinim OSD Pins

The first step was to solder on the 90º headers to the FTDI pins. Connect the inner pins and just leave the second row hanging out in space like this:

90º Pin header soldered to a MicroMinim OSD

And from another angle:

90º Pin headers soldered to a MicroMinim OSD

Then connect the video in and out pins on the side of the board to those spare pins using short lengths of wire. I used some offcuts I'd removed from an ESC.

Pins connected with short lengths of wire

There's nothing like a close up to make you soldering look bad so I quickly hid my crimes with a coat of Liquid Electrical Tape. 

Solder covered in Liquid Electrical Tape

Then I wrapped the whole thing in some clear heat shrink so the indicator lights were still visible and hooked it up to my laptop with a simple FTDI programmer and some DuPont jumper wires to update the firmware.

I didn't actually need to update as it is already flashed with MWOSD R1.3 but 1.6 is out and I am that guy! You can get the GUI for 1.3 here and skip the whole flashing thing. Version 1.6 is over at mwosd.com too.

If you are going to flash a different firmware version you are going to need the Arduino IDE to do it. I won't go into what that is here as it's beyond the scope and in this instance, it's just a tool we are going to use to to put firmware on our board.

Plug in your FTDI programmer and wait while Windows realises it's a COM port. Then browse to the folder you extracted the MWOSD firmware into and double click the MW_OSD.ino file. That will load on into the Arduino IDE. Now, under the Tools menu, set your COM port and board type. Your COM port may be different, if you have a few, see which one appears when you plug the FTDI programmer in.

Auduino IDE

Click the right facing arrow icon and boom, your OSD is flashed. Now to to the GUI to configure things.

There are a heap of things you can turn on and off here but I suggest keeping things simple. I generally keep it down to voltage and amperage, RSSI and time but you can learn what all the other option are in the MW OSD docs.

All you need to do now is actually install it on your quad and that's just 4 wires. You need a 5V supply and a ground that you can take from an unused Naze32 motor output or a SPRacingF3Mini dedicated 5V pin. And you need a connection to a serial port (aka a UART) on your flight controller. The Tx and Rx pins in the middle of a Naze32 are perfect or UART1 on a SPRacingF3Mini. Make sure Tx goes to Rx and Rx goes to Tx and turn on MPS for that port in Cleanflight/Betaflight and you are good to go!

If you have any questions, drop me a line, or leave a comment.

1 comment

Great guide thank you…

David Owens

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