■ FIGURE 6. Fritzing
FTDI USB to TTL
■ FIGURE 5. Adafruit FTDI Friend.
ROLL YOUR OWN ARDUINO
Why would you want to do this? Arduinos
from the actual Arduino folks are cheap
compatible clones from all over the planet are even
cheaper [though not necessarily as reliable as the
'real' thing. Also, no money goes to the Arduino
core team for further development of the Arduino,
so please consider buying from the Arduino folks.]
There is simply no way that you are going to build
an Arduino cheaper than you can buy one (if your
time accounts for anything). Further, if the Arduino
doesn't do exactly what you want, you can get
shields for it and there is almost certainly somebody
selling a shield that will do what you want for less
than you can roll your own — so why bother?
Well firstly, you might, for instance, want to add
something to the Arduino board that nobody else is
making at the moment. Or, secondly, you might just
want to learn how to do it because you are one of
those pesky curious folks who just wants to know
how to do stuff. And, thirdly, you might want to
combine your shield design with the minimum
Arduino circuitry all on a single PCB. In which case,
you might save some money by rolling your own.
There might even be a fourthly or fifthly, but
whatever '#ly' your reason is, let's start rolling.
■ FIGURE 7. Fritzingduino (no shield) breadboard view.
■ FIGURE 8.
Specifying a Minimum Arduino
I'm not sure anybody knows exactly what a
minimum Arduino is. It probably should have a
microcontroller with an Arduino compatible
bootloader that can communicate with the IDE
(Integrated Development Environment), can use the
Arduino library, and can be identified in the IDE
Tools\Board list. Also, if it is to make claims about
being PCB compatible, it should probably have the
exact header pin layout for one of the Arduino boards so
that it can use standard shields. It probably should also have
some way to provide power to the board besides the USB
connection. So, let's specify a minimum Arduino that will
and take external battery power through a barrel
connection to provide the needed voltage:
1. Atmega328 with Arduino bootloader in memory.
2. PCB with the Arduino UNO R# header pin layout.
May 2013 71