# Over engineering a game of Lights Out

[Bertho] might have outdone himself this time. He built a Lights Out clone for the 7400 logic competition.

Lights Out is an electronic toy sold by Tiger in the mid 90s. The goal of the game is to turn a 5 by 5 grid of light up buttons off. There’s a catch, though – pressing a button toggles the state of the four surrounding buttons. Check out this Flash game that’s faithful to the original.

[Bertho] read a few Lights Out fan pages and set out to design the circuit. Most of the build is made up of shift registers: the ‘game state’ is saved in five 74hc164 shift registers and a 4557 programmable register. The board is set with a random number generator that toggles bits in the game register until a solvable puzzle is found. A truly spectacular build.

For the light-up buttons themselves, [Bertho] found an old Hack A Day post that describes putting tact switches underneath a LED. The project was put into a nice Plexiglas enclosure after 15 hours of soldering. [Bertho] was kind enough to put a video up of the game in action. Check it out after the break.

## 7 thoughts on “Over engineering a game of Lights Out”

1. EccentricElectron says:

Now that is a hack. Awesome work!

2. Jriddles says:

Simply amazing. The idea that a game like this can be constructed out of such basic logic components just blows my mind. Screw MCUs, where does one learn this wondrous art?

1. Bertho says:

You learn it by 1) starting small, 2) be very persistent and 3) try and try again. Being a bit crazy might help here and there too ;-)

Serious though, know your boolean algebra, Moore vs. Mealy state machines, sync. vs. async. counters, the various flip-flops plus (shift-)registers and a lot of creativity how to do reductionism. Sometimes, you need a tangential approach when using logic. And, just like in programming, there are many design-patterns you see repeated all the time.

2. mjrippe says:

Get a copy of the TTL Cookbook by Don Lancaster. Many used copies available cheap online.

3. Jan says:

what a beautiful machine!

4. blue carbuncle says:

Dude the best part of Lights Out is the nerd drama that ensued when one fella figured it out and then decided to not share it with the math community and instead sell it. This led to another member figuring out his method and posting it online for free iirc. I remember lmao while reading the forum posts but that was over 4 months ago when I picked one up at the thrift. I’ll have to look it all up and post the link, bc I think HaD readers would enjoy the old school battles.

BTW CONGRATS ON THE BUILD!!!

5. MaZtRHaXoR says:

Where can I get a schematic for this? I really need one -.-

specifically a 3×3 one, but any schematic will do, thanks in advance :)