Build a GIF-Powered Magic 8-Ball

You can find the parts packed in a tidy .zip over at Element14. I’ve included the full assembly as a STEP file in addition to the individual STLs, so you can modify the design to your heart’s content.

There are seven parts to 3D print: the upper shell, lower shell, bezel, LCD retainer, mounting block, logo insert, and button retainer. I printed mine out of PLA at a 0.2mm layer height, but at higher resolutions your sphericity will of course be much better. For the shells, I recommend printing in dome vs. bowl orientation as this is less likely to warp.

Print the logo vertically, as the X-Y axis is much higher resolution than the Z (the logo is a very shallow curved piece, which is a challenge for all FDM 3D printers).

Depending on what color filament you used, you’ll need to paint the shell and/or the logo pieces. If you print the logo in black, you can coat it a solid white and then scrape away (once dry) within the letters to reveal the black underneath, or as I did in the original version, use a fine tip brush to fill in the letters.

I’m not a fan of hand painting, but perhaps you have steadier hands than I!

There’s very little to do Linux-wise to prepare your Pi. First, flash the latest Pi OS onto your microSD card (Raspbian Lite is OK as the screen is run directly and doesn’t mirror the X framebuffer). Raspberry Pi’s new imager tool makes this all much more streamlined if you haven’t heard the word.

Get ready for basic headless setup by entering your Wi-Fi credentials. Once connected via SSH, you’ll need to install the ST7789 Python module from Pimoroni by entering the command:

sudo pip install st7789

They recommend installing some other common modules first, but I found that these were already up to date in the current OS. Also, be sure to run sudo raspi-config and enable I²C and SPI.

Before connecting any other components, let’s test our little TFT LCD display to make sure we’ve connected it properly and the software is good to go. With the Pi unpowered, use the female jumpers to make the following connections between the LCD and the Pi; they’ll communicate using the SPI serial protocol:

• 3v3 to any 3V pin
• TCS to Pi pin 7 — this is the SPI chip select pin for the TFT display
• SCK to pin 11 — the SPI clock input pin
• SI to pin 10 — the SPI MOSI pin (microcontroller out, serial in) to send data to the display
• D/C to pin 9 — the SPI data or command selector pin
• BL to pin 19
• GND to any Pi ground pin

Double-check your wiring, boot up the Pi, and cd into the folder st7789-python/examples. Then call:

python3 gif.py

And you should be greeted by Pimoroni’s colorful “Deploy Rainbows” GIF.

The classic toy is restricted to a mere 20 answers, but we, dear reader, live in the future! Our GIF-Ball can for all intents and purposes house a virtually endless array of images, answers, and, most importantly, memes! So don’t hold back when it comes to selecting your reply set.

If you’re an 8-Ball purist, the original had 10 positive, 5 ambiguous, and 5 negative replies, so a mere 20 GIFs will be sufficient to capture that classic fortune-telling experience.

There are preselected GIFs in the download package in the Images folder, but if you’re selecting your own, try to find images with a more square aspect ratio. The code will accommodate different image sizes and naming schemes, but keep in mind that while the mini IPS display is crisp, it’s still only 240 pixels wide. Any image that ends in .gif will be randomly selected as a response.

Once you’ve curated your preferred selection of GIFs, it’s time to slap ’em inside the Pi. Navigate to the directory on your main computer where you’ve got all your images, as well as the main program (fortune.py), and transfer them to the Pi via SCP (Secure Copy). For example:

scp *.gif pi@raspberrypi.local:
scp fortune.py pi@raspberrypi.local:

Your GIFs and the program should now be in /home/pi so you can now test it with:

python3 fortune.py

Tip: Learn more about using Secure Copy at raspberrypi.org.

We haven’t connected the tilt sensor yet, but you can short BCM pin 2 to GND and the program will register that as a “shake.”

There are several options to have a program autorun, but we’ll keep it simple. Just call:

sudo nano /etc/rc.local

After the line exit 0, add:

sudo bash -c '/usr/bin/python3 /home/pi/fortune.py’ &

Cut a female jumper in half and solder the halves to the leads of the vibration sensor.

Solder a strip of 8 right-angle male headers to the PowerBoost side connections, and a strip of 4 to the power pads.

Solder the JST socket to the pushbutton power switch (PPS) (red to IN, black to a GND connection). Add 3″ leads to the pushbutton and solder to PPS pads 1 and 3. Cut and solder a red jumper to the PPS OUT pin.

Cut and solder a black jumper to the G pin of the PPS.

You already connected the LCD in Step 4. Now, connect a jumper from the Pi’s 5V pin to the +5V pin of the PowerBoost, and another jumper from a Pi ground pin to a GND pin of the PowerBoost.

Connect the jumper from the PPS OUT pin to the Bat pin of the PowerBoost. Connect the PPS G pin to a GND pin on the PowerBoost.

Lastly, attach one of the sensor pins to pin 2 on the Pi and the remaining pin to a GND pin on the Pi.

Mount the switch in the square hole within the logo, using two M3 screws.

Glue the logo insert into the lower shell.

Test-fit the clips in their matching holes, making sure they all seat at the same level when fully inserted.

Put a couple drops of super glue on their tips and press them firmly down.

Screw in the LCD retainer with two M3 screws, then the bezel with two more.

Place the Raspberry Pi over the four mounting holes and align the mounting block above it, fastening it in place with four M2.5 screws.

Insert the battery.

Insert the vibration sensor into one of the holes on the side of the mounting block.

Secure the PowerBoost to the mounting block with two M2.5 screws.

Wait a few hours for the glue to fully cure, then connect the two halves together, making sure not to pinch any stray wires.