Using ATMega328 Microcontroller Custom Tron Disc Mod

In this Instructable, I cover modding the store-bought Deluxe Identity Disc to an upgraded version with 64 leds, controlled by an AVR MCU. The upgraded version is costume-ready and would be an excellent addition to your Tron costume – it’ll also look great on your desk/dresser/etc.
My 7 year old daughter watched Tron:Legacy with me on Father’s day and decided instantly that she wanted to be Quorra for Halloween. I knew the costume would be a decent bit of work, and I don’t sew (although I will be getting assistance making the costume – hopefully a forthcoming instructable) – I decided to start with the Identity Disc.
I managed to find an identity disc at Target for $9 on clearance (they can be found on Amazon for $12 as of the writing of this article). However, when we brought the disc home, I was seriously disappointed at the lack lighting. So – like any good father would do – I set out to upgrade the disc.
Please note that this project does not preserve the original sound – I’d really like to include something, but didn’t find any AVR examples I really liked. If you have any suggestions for sound inclusion – please share!
Before I start the article – and before people say they can’t do this themselves – let me be clear about my qualifications. I’m a Software Developer (.Net). I’m not an electrical engineer, my soldering skills are sub-par, and even though I’m a developer – my AVR code is probably horrible. If I can do it, anybody with a lot of patience and time can as well.
And take it easy on me – this is my first Instructable!
When I started my research – I ran across this article: Tron-Disc-with-NET-Microframework. Fantastic implementation – all LEDs can be controlled individually, adjustable brightness. Then I noticed the huge board in the middle. And the expensive cost of the hardware, etc. I needed something that wouldn’t break the bank, and parts that I could fit in the disc.
But first – let me leave you with a little teaser video. This is what the device looks like with the V1 firmware.

LED Display Driver

• Tron Deluxe Identity Disc
• 3 x AAA alkaline batteries – any battery source between 4 and 5.5v would work, but you’re limited on space
• 64 LEDs (I bought a set of 100 blue on Ebay for $3.50 including shipping)
• ATMega328/168 or ATTiny45- I was able to get free samples from Atmel – warning – they’re much more difficult to obtain than Maxim
Any AVR chip that supports SPI/USI and has an additional 2 input pins would probably work as well
• Max7221 or Max7219 LED Display Driver – I was able to get free samples from Maxim – they provide samples fairly freely

I have not tested with the Max7219 – but from what I’ve seen online, these should be interchangeable
• 50+ feet of 30awg wire – seems like a lot – but you’ll need it
• RSet Resistor – I needed a 15k resistor – this helps the LED Driver determine what current/voltage to use
See this page for more information on values
• Solder (I suggest something small like 0.032)
• Perfboard – a small sheet is all you’ll need.
You’ll want the kind with the copper rings. Veroboard would probably work as well, but it’s more expensive
• 24 pin DIP IC Socket (Optional – used for the Max7221 – I don’t trust myself to not fry the IC)
• 28 pin DIP IC Socket
• Two pens with springs
• Hot Glue Sticks
• cyanoacrylate
• Magnetic Reed Switch – I used the glass kind
For the second disc, I used a COTO-20 I purchased from eBay. For the first disc, I harvested one from a broken child’s toy

Soldering Iron – I’m not using anything fancy – just an $8 iron from RadioShack
Soldering Helper – Not sure what it’s really called, but it comes with the RS Iron – it’s a thin tool that I used to help route wires, wrap wire, etc. It proved invaluable. This or a similar tool will come in handy.
Dremel, cut off disc and engraving tip (Optional, but highly suggested)
Wire cutters
Wire stripper (Optional – finger nails work very well on 30awg)
AVR Programmer – I use a $6 USBASP programmer I found on eBay
Silver Sharpie (Optional)
Hot Glue Gun
Pliers – ideally a small pair

Gut It!

BEFORE YOU START – Get yourself a zip-top bag.  You’ll probably want to save all of the original parts.  If you want to expand on my design, some of the extra pieces might come in handy.

Dis-assembly is fairly simple.  Start with the six screws on the back and the battery compartment to open.  The rest of the process should go fairly quickly.  No prying should be necessary.  Remove the batteries as well.

Read more: Using ATMega328 Microcontroller Custom Tron Disc Mod

Leave a Comment

Your email address will not be published. Required fields are marked *