View Full Version : Game of Life on Propeller with LED Matrix

05-26-2010, 12:40 AM
Since there was a discussion the last week or two about interfacing a LED matrix to a prop, I thought I'd share my latest prototype. It's Conway's Game of Life implemented on a prop with an 8x8 LED matrix.

The anodes were sourced via 100 ohm resistors directly from the prop. Cathodes were sinked via a ULN2803 darlington array. I operated the display in a straightforward common-cathode manner, energizing the cathodes one at a time while setting the appropriate 8 anode bits. The design used 16 IO lines from the prop. As discussed in the other threads, this could certainly have been reduced by using latches or shift registers. However, the sole purpose of the board was to operate the display, so only half of the prop's IO pins were even needed.

There are empty pads for mounting a dallas RTC, and headers for joining multiple boards into a grid should I ever choose to do so.

It's also my first SMD board, and I'm pleased to say that I assembled it correctly and it powered up the first time with no problems!

If I'd had it to do over again, I might have mounted the display to the opposite side of the board rather than putting it on the same side as the components.

05-26-2010, 02:16 AM
I think that's dead cute. Great for simple displays with cogs and pins left over for other purposes. How can I get one ?

For me, the past is not over yet.

Phil Pilgrim (PhiPi)
05-26-2010, 02:36 AM
Very cool! Now, I see some unpopulated pads on each edge of the board. Are these for R/A connectors so multiple boards can be connected to make a larger display?


05-26-2010, 02:46 AM
Very cool project. Reminds me of a mini version of the Spare Time Gizmos's life display/clock.


I built one from the blank PCB and have it hanging up at work.


05-26-2010, 03:29 AM
Nice work.

May the road rise to meet you; may the sun shine on your back.
May you create something useful, even if it's just a hack.

05-26-2010, 04:37 AM
Yes, the pads on the size are intended to allow multiple modules to be connected. Each one has +3V, GND, and two unique prop pins with provisions for current-limiting resistors. I haven't thought through exactly what my plan was for linking multiple modules, but it seemed reasonable to layout something onto the PCB for future use. My intention was to use right-angle headers, although I haven't fitted them, so I don't know if they'd leave a gap between modules. Might take a little bit of trimming.

The Dallas RTC pad and crystal are intended so I can make a binary clock out of one of the modules. Creating a binary clock was my original plan when I got started tinkering with props last year and strangely enough remains the one project that keeps getting pushed off into the future.

As far as how to get one, I wasn't really planning on selling them. The layout is at batchpcb.com, so I could make it publicly available for ordering if people were interested. The biggest issue is the matrix display. It's an 8x8 matrix that I believe came from 'All Electronics'. I think they were surplus and aren't sold there anymore. I have been able to find similar matrices on ebay from China or Hong Kong that can be ordered in 10-quantity, but I haven't been able to find them in small quantity at any US part houses. The matrix has a rather strange and inconvenient pinout. At the time, I couldn't even get a datasheet and had to figure it out on my own, which was a bit tedious.


05-26-2010, 05:37 AM
that is very cool. you can use some HT1632C IC to drive 6 matix and also have PWM control, Display RAM.

05-26-2010, 07:12 PM
Great job! I was just thinking about doing the same thing with my Prop powered 8x8xRGB matrix board. But, now I have to think of some other clever demo :(

My Prop Info&Apps: ·http://www.rayslogic.com/propeller/propeller.htm

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