Just yesterday I received my Arduino Pro Mini (US$ 4.00) and a USB to serial FTDI programmer unit (US$ 2.00). I’m amazed at the price of these little devices. They’re so incredibly cheap!! I needed these to complete work on my Nikon IR Remote Hack Project.
The Arduino Pro Mini is a 5V 16 MHz with ATmega 328 onboard. As you can see, the board is very small. It comes with headers that need to be soldered into place. While this may seem a little daunting at first glance, it turned out to be surprisingly easy and in less than 10 minutes, I had all three headers soldered in place. You just need to make sure that you don’t overheat the board while applying the soldering iron.
If you look closely, you’ll notice that pins A4 and A5 are not along the edges of the board like the other pins. Also, pins A6, A7, one of the GND and one of the Voltage pins (Near the little RESET button) have not been soldered to headers. I think the designers wanted to keep the size as small as possible and so some of the pins are not intended to plug into a standard breadboard and are probably meant to be soldered onto a PCB without being tested on a breadboard first.
The USB to Serial FTDI programming interface is needed to upload programs from the Arduino IDE on a PC to the Pro Mini. As can be seen, this is a also tiny little unit with serial communication pins on one end and a mini USB connector to connect to the computer’s USB port on the other end. I’m amazed at the price of this unit – just US$2.00!!
Strangely enough, I could not find any simple tutorials on how to connect the FTDI interface with the Arduino Pro Mini and I hope this image clears things up. As you can see, all we need to do is make sure that the pins connect in the correct sequence, using the markings GRN (green) and BLK (black) as references. So GRN connects to GRN, BLK connects to BLK and the intermediate pins connect in sequence.
I used jumper wires and a breadboard to connect the Arduino Pro Mini to the FTDI programmer.
Next, I built a little test circuit using an LED and a 200 ohm resistor. The LED is in series with the 200 ohm resistor and is connected to pin 5 and then to GND.
Using the Arduino IDE, I wrote a simple LED flashing program and uploaded it to the Pro Mini via the FTDI interface. The procedure is exactly the same as when using an UNO or a MEGA. We just need to be sure that we have selected the ‘board’ correctly before performing the upload.
Also, if you’re buying your boards from ebay, make sure you know exactly which one you are buying. Also, remember that some Pro Mini boards run on 3.3V and other on 5V. Be very careful in choosing your power supply.
Here is my youtube video on getting started with the Arduino Pro Mini.