This little article covers the steps needed to use an arduino Uno board as USB-Serial adapter for Meduino Pro Mini, another well done Arduclone.
Well i want to avoid an USB-FTDI serial adapter in order to upload sketches to my Meduino Pro Mini.
It is a good cheap ebay-ish Ardu-clone, in fact it has a 3-5 Volts Switch, that, compared to the Arduino Pro Mini, avoids a couple of pins, thus SDA and SCL are no more “hidden” but exposed and well wired, much more comfortable. On the other side the Arduino Mini Pro (used this other article for a Multiwii project from scratches) can deliver both 3 and 5 Volts simultaneously and also has more leds (tx and rx are missing from Meduino Pro Mini).
It misses also the USB port and, consequently, the onboard adapter too. So If you don’t want to buy an FTDI USB-Serial adapter (like me) and want to use your other arduino model with an USB port, just remove the microprocessor from the Arduino Uno, and then connect the following pins as described:
Arduino Uno 5V -> Meduino Pro Mini Vin
Arduino Uno GND -> Meduino GND
Arduino Uno Pin0 (RX0) -> Meduino Pro Mini Pin1 (RX1)
Arduino Uno Pin1 (TX1) -> Meduino Pro Mini Pin0 (RX0)
Arduino Uno Reset -> Meduino Pro Mini RST
This way, the Arduino Uno will act as usb-serial adapter for Meduino pro mini.
In this pic i used a mini breadbord to put things together and save some space.
Using The IDE
To upload sketches with the Arduino IDE, just attach your sandwich to your pc with the usb cable, open uo the ide and select your model from the drop down, in this case our model is not listed, for this reason we will choose:
“Arduino Pro or Pro Mini (5V, 16Mhz) w/ ATmega328”.
p.s. You can try with a simple sketch like the blink (the Meduino Pro Mini blinks on Pin13 with no need to add a led).