Life Is But a Game by Tinkersoc

The Hardware Brief

• To build a 10 x 10 matrix of lights that can play the Game of Life (GOL).

• The matrix must be controllable from an external source (the display only needs to render the GOL, it does not need to run it).

• A high quality finish is required.

Initial Concept

100 ping pong balls + RGB lights = win.

Sourcing Lights

• Due to the size of the matrix we can’t plug in lots of lights into a micro (100+ pins needed!).

• Multiplexing is one solution: ▪ This would provide very

fast IO to render an image, but adds complication to the wiring of the device.

Sourcing Lights

• We don’t need fast refresh rates (the GOL will be slowed down a lot due to the ‘limited’ size of the screen).

• Addressable RGB lights would give us expansion room (replacing or adding pixels would be easier)...

Enter the WS2801 and the WS2812B

WS2801 & WS2812B

• 2 wires (ws2801B) and 1 wire (ws2812b) required to control a huge string of LEDs.

• Very bright RGB and individually addressable.

• Although timing is sensitive (would require FPGA or some fancy DMA on very large strings) we aren’t running that many LEDs (100 is relatively small).

• 100 of these LEDs would need a fair amount of ‘current’ at 5V, but easy to supply (10A external psu).

Prototype 1.

• 5 x 5 Matrix using a WS2801 string.

• Bit of hardboard.

• Arduino.

Designing The Final Hardware

• WS2812b tape (very cheap per LED).

• IKEA HOL table (A 10 x 10 lattice!).

• Wire.

• Front one-way-mirror.

A Lot of Soldering Later…..

If YouTube decides to work…. http://www.youtube.com/watch?v=M7ut70dOd7o#t=192

Version 2

• Soldering by hand is slow and potentially unreliable.

• Time to produce some PCBS. !!!!

• Produced in KICAD. ▪ Each strip contains 5 LEDs (will need 10 strips of these). ▪ Surface mounting each led and a capacitor. Fits nicely in

the lattice gap.

Result:

All in:

PLUGGED IN AND…..

DISASTER! ☹

Diagnosis – Why is my LED not working?

• Power is fine (5V consistently across the power rail).

• No shorts.

• Can run an individual stick.

• Should be working and we have yet to diagnose what is wrong (probably something messing up the signal).

A FEW DAYS LEFT AND WE HAVE NO DISPLAY!?!

The Society To The Rescue – Scrapping the design and going Plan B.

• KISS approach (This had got lost along the way.)

• Many Tinkersoc members = many man/woman hours.

• More eyes to check the work.

• A fun evening of building (make this an actual Tinkersoc project).

Day 1 - Case Design

• Custom case was designed in autoCAD

• Lasercut by architecture department (took over 1 hour to cut all the MDF).

Day 1 - LEDs

• Back to the WS2801s (same as those used in the prototype). !!!!!!

• Kiss again: 100 LEDSs prewired purchased and measured to fit the custom case. Arrived day 2.

Day 1 - Software

• Arduino micro setup with GOL firmware.

• A PhD student wrote this. Uploaded and tested.

DAY 2: BUILD.

Lessons Learnt

• Things can be swimming along fine and fall over when you least suspect it (generally right at the end).

• KISS is the best approach (as long as you KISS the right thing).

• Your society can save your butt.

• I love the smell of laser’d MDF in the morning.

Life Is But a Game by Tinkersoc