Wednesday, May 4, 2011

Conway Life - redesign of Ladyada's board

I described this project first on the (DP forum text follows with some edits):

I designed small 2-layer PCB for a version of Ladyada Game of Life. The board is two-side, front has 16 0603 LEDs on it, back has ATTiny861, 4 resistors, 4 FETs, 2 capacitors and one button.

The board was prototyped through Laen's PCB group order.

One side with TQFP processor was soldered on a hot plate, 16 LEDs on the other side soldered manually.

The board's firmware is not ready yet - the processor is quite different from the original ATMega 168 - less pins, less memory, fewer timers etc.

The LED activation is implemented as 4 x 4 matrix with columns connected through FETs and rows connected through limiting resistor directly to ATTiny. The idea is to activate one column at a time - thus FETs, and light up to 4 rows for every column - so we can get away with direct connection of row to processor pin.

The board is alive - first test lights the LEDs and senses the button.

Next step is a full port of original firmware with communication protocol - the boards can be connected to form large Game of Life field.

I'd appreciate suggestions on cheap 4-wire side connector.

--- end of quote ---

Here is further details on the project that seems to be interesting for me. Recently I learned through Laen's tweet about nice ISP connector for AVR boards: . I faced with analogous problem - the main curse of miniaturization is connectors. I have four communication connectors for proprietary (if you can say so about open) protocol, and ISP connector to program the beast. If you look at the photo

you'll see that the left side looks more populated with these nice golden strips. Upper three of them is an upper part of shortened board-side ISP connector I use on some of my boards. The layout is a standard AVR ISP 6-pin put on a board's side. I use a small adapter board with similar connector and solder bent pins to it, not unlike a SDcard breakout with headers. This is the header:
This is how it is connected to the board:

The board is still to be programmed, I port Ladyada's software slowly.