Last year for Halloween, HaHaBird - aka Nathan Pryor, illuminated the Instructables community with his Pumpktris. This was one of the coolest Instructables ever posted. Now that we here at Instructables are neighbors with the wonderful, magnificent, science-tastic Exploratorium, we worked with them this year to make a GIANT version of Pumpkin Tetris, which was exhibited during their Halloween festivities.

Step 1: Materials

For this project I used:
Materials:

2 Pumpkins (One giant pumpkin, and a little guy for the controller)
128 10mm LEDs
1 Joy Stick
2 8x8 Grids/Backpacks
1 Arduino
a LOT of wire
heat shrink
electical tape
flux
drywall anchors
coupling nut/50mm extension bolt - 6mm diameter

Tools:

exacto knife
snips
heat gun
wire stripper
soldering iron
drill - 1" hole saw, and 13/32" bit for LED holes
hacksaw

I also used a laser cutter to make a jig, more on that later

Step 2: Building the Circuit

I used Nathan's Instructable to guide me in building the circuit, and programming the Arduino. It was stone simple.

I marked up the joystick with tape and a sharpie so I could remember the orientation of the controller before I jammed it in the pumpkin - I also machined out some slightly larger holes to make it easier to mount the joystick in the pumpkin.

The Arduino requires the following libraries from Adafruit:

And here is the sketch

A small understanding of how these microcontrollers function is helpful when building these kinds of projects. I had to do a little fussing in the sketch when the joystick wasn't communicating in the way I had initially anticipated.

Step 3: Jig for Assembling Matrix

In Corel Draw, I made a matrix of 16x8 10 mm Holes, then used an Epilog laser cutter to cut 3 sheets of cardboard. When the sheets came out of the laser cutter, I taped them together.

The LEDs fit nicely in there, and didn't wiggle around too much when I moved the matrix around.

Step 4: Assembling the Matrix

Building the matrix takes time. Like, a lot of time. I methodically moved through and used Nathan's very helpful diagram to create the matrix.

Heat shrink every junction of wire to LED lead, as you don't want ANY MOISTURE creeping into your circuit. I heat shrunked (that's a word, right?) every LED, and then wrapped it in electrical tape.

It was helpful to use flux to get the wire junctions to solder properly together. I used a junky paintbrush to coat the leads as I was soldering. I also made hundreds of Jumpwires using my Jumpwire Jig.

Did I mention this part takes time? It took me like four nights of mellow music, and a few beers, to do this part.

Step 5: Carve That Sucker!

Our neighbors at the Exploratorium were kind enough to get us a HUGE pumpkin to carve Tetris into. I made a timelapse video of hollowing out each pumpkin. Finding a good flat orientation took a little bit of work. I used masking tape to mark off where the grid should go.

Don't try and use an electric carving knife for this job - I found that the best tool for the pumpkin carving was the cheap-o carving knives you get from the grocery store. Using a nicer knife proved to be unwieldy. The tiny serrated pumpkin knives were perfect.

For the LED holes, I used a 13/32" drill bit.

I used an exacto blade to carve out the front of it, and slowly shape allllllll the squares into the pumpkin. Be careful when using all of these sharp implements, I sliced the back of my thumb when the blade flipped out of my hand from applying too much pressure.

Carving delicately into a pumpkin is a lot like working with soft clay. A light touch goes a long way.

Step 6: The Controller Pumpkin

Again, using HaHaBird's instructable as a reference, I carved the controller pumpkin. I sawed off the top of the stem as close to the pumpkin as I could, and then drilled a 1/4" hole into the stem. I connected the controller to the stem with gorilla glue, and mounted it in the pumpkin with dry-wall anchoring screws.

I soldered long extension wires from the controller pumpkin to the display pumpkin. Again, carefully moisture proof all your wires - they are going into organic material.

Step 7: Testing

As I was carving out the front of the pumpkin, I was also testing it. This was a good way to make sure it worked, and see which LEDs needed a little extra support. Patience for repetitive carving is critical, this is a timely process.

Step 8: Exhibiting the Pumpkin

This piece was featured at the Exploratorium for the Halloween events, and it was a great opportunity to talk about maker culture, Instructables, and tinkering at such a cool venue! We sparked a lot of community interest, and I can't wait to see what kind of projects our new neighbors post to the site!

As a side note, a lot of the kids playing the pumpkin HAD NEVER EVER PLAYED OR HEARD OF TETRIS BEFORE!!! I got multiple asks if it was a mine-craft pumpkin. It was great to see parents explaining to their young ones what tetris is, and then crush it while playing the game on the pumpkin.