- 2 ATTiny84 microcontrollers
- 3 Ceramic resonators at 20MHz
- 3 5V regulators
- A 14 pin DIP socket
- Female Headers like on sides of Arduino boards
- 25 PNP transistors
- 25 NPN transistors
- 50 1k ohm resistors
- 50 10k ohm resistors
- 10 10uF Capacitors
- 3 Slide switches (for power on/off)
- 2 2.1mm barrel jacks
- A programmer kit from adafruit
- A 2.1mm male barrel jack with screw terminals for wires (batteries)
Using a few of all of these parts, I plan on creating an evaluation/development board (I'm not sure the difference between the definition of an evaluation board vs. a development board) for the ATTiny84 microcontroller. This will be complete with:
- A Power Jack for DC power (5-18V)
- A 6 pin Serial connector for a programmer
- Easily accessible female pin headers to quickly hook up wires to each IO of the board.
- A 20MHz clock to take full advantage of the microcontroller instead of using the 8MHz internal clock (possibly more work than it's worth unless this is involved in an important real-time system like a segway-bot)
- A reset button
- An LED indicating power to the board.
This definitely isn't going to be anything special or pretty to look at. I think I'm going to use Radio Shack's perforated board with wires all over, although I'm going to try to keep it small (Tiny) and relatively clean looking. I bought extras of everything to be able to redo parts if something accidentally goes wrong. This is starting to look like a fun project and definitely the first time I've ever tried anything like this.
Once a board is programmed it can easily be taken out of the development board and put into a more permanent board for use.
I quickly made a sketch as to how things will be wired up:
And tomorrow night I'll start designing on this template (yes, graph paper would've been easier) to make the actual layout on the perf board. Every intersection of lines represents a hole in the perf board, and in real life they're .100" apart.
EDIT: I added a 10uF capacitor between Vcc and ground BEFORE the 5V regulator to even out the incoming voltage before the regulator even touches it. I wasn't sure if this was needed before, but somewhere I read that it couldn't hurt.
All together this board is going to cost me less than $10 including the $3 perf board. The microcontrollers then are about $3.01 each when I go through them. This has got to be one of the most fun and inexpensive hobbies a guy could ask for!