I assume you have either made the leap from the Arduino Duemilanove to an Arduino Pro Mini or you are contemplating to do so. In a nutshell the Arduino Pro Mini is basically an Arduino Duemilanove ATMega328 without a USB port and FTDI chip. It’s a really small board, approximately 0.7″ x 1.3″. You can find Arduino Pro Mini’s in semi-permanent installations, in objects or exhibitions, where the engineers had limited space or wanted to conceal the micro-controller.
It’s pretty much my go to micro-controller when prototyping interactive applications. A side from being tiny, it’s the least expensive of the Arduino family, at $18 a piece. Since the Arduino Pro Mini does not have a USB port or FTDI chip, you will need a serial connection to program the board. I recommend the SparkFuns FTDI Basic board.
You only have to buy one FTDI Basic board, to program as many Arduino Pro Mini(s) you can afford.
The Arduino Pro Mini comes in two flavors, 3.3 volt or 5 volt. I prefer the 5 volt option. I alter the voltage when need be, especially when working with sensors that operate at 3.3V . A few other things you will find a bit different migrating from the Duemilanove are the RAW, VCC and RESET pins. The RAW pin enables you to supply the board with a raw unregulated voltage (5-12 volts, depending on the model). The VCC pins requires a regulated 3.3 or 5 volt supply (once again, depending on the model) to power the board. I usually power the board via the RAW pin and use the VCC pin to output a regulated 5v power source. The RESET pin is typically used to add a reset button to shields which block the one on the board.
You will notice that the board has analog pins 4(sda) and 5(scl) on the interior of the board. Pins 4 and 5 have a specialized functionality. The pins are used to support I2C (TWI) communications using the Wire library. That pretty much sums up the differences between the Duemilanove beginners board and the Arduino Pro Mini. I love the size of the Pro Mini. It compliments most of my prototyping applications and gives me the inputs and outputs I have grown to love from the Duemilanove.
I recommend you take an Arduino Pro Mini and set it up to be Breadboard friendly. To do this you will need a medium size Breadboard, a set of straight headers and (optional) a set of Right Angle breakaway headers. The next steps provide you with info on how to set up your Arduino Pro Mini to be Breadboard friendly.
Take the break away headers and cut them to fit the Arduino Pro Mini. You will need (2) 12 pin headers, (1) 6 pin header and (1) 2 pin header.
Now get your soldering iron out and lets solder the headers onto the board. The first thing I do is solder the 6 pin header to the top of the Arduino board. This is where the Arduino board will connect with the Basic FTDI board. I prefer to use Right Angle headers for the 6 pin. Place the 6 pin header on the Arduino board and flip the board over keeping the header pins in place and solder. Take a pair of wire snipers and snip the excess wire from the bottom of the board to allow the Arduino Mini to set flush up against a Breadboard. You should now have an Arduino board that looks like this (if you used the Right angle header):
Next, grab the medium size Breadboard and insert the 2 pin header into the Breadboard (shorter side of the pins up). Then flip the Arduino board over (backside up) and set the analog A4 and A5 holes of the Arduino onto the header pins. Align the Arduino board parallel to the Breadboard and solder. When you are done grab your snipers and cut the excess wire on the bottom of the Arduino board. You should now have 2 pins sticking out of the top of the Arduino board, enabling access to analog pins 4 and 5.
Placing the headers on a Breadboard prior to soldering helps, keep the Arduino Mini in place. In the next step we use this technique to add the 12 pin headers.
Simply place one of the 12 pin headers (short side of the pins up) onto the Breadboard. Place the Arduino Mini (top side up) onto the header. Take a mental note of the placement of the holes in relation to the Breadboard and place the other 12 pin header in its place. You should now have a stable Arduino Mini sitting on top of the 12 pin headers. All you have left to do is solder the headers in place. The end result should look like this:
That concludes my instructional.
I have one more cool tip for you. Look into Modern Devices wired Breadboard. They make a foolproof beginners PCB board that enables you to transfer your project directly from your solderless breadboard to the PCB, now that’s cool! This is just the tip of the iceberg, I will release other topics primarily featuring the Arduino Pro Mini, so subscribe to my RSS feed to get the latest and greatest on my Arduino adventures.
Till next time, Enjoy!