Magnetic Seeed EE04 + Spectra 7.3"/BW 7.5" E-Ink Case

Overview and Basic Info

I wanted an E-Ink calendar display for my fridge so I made this. This model is designed for the Seeed Studio EE04 board, paired with either the 7.3" Spectra 6 raw panel, or the 7.5" monochrome raw panel (both panels have identical outer dimensions). The entire case is less than 15mm thick! 

One big benefit of Seeed's XIAO EE04 ecosystem over Waveshare and most other ESP32-driven E-Ink panels is that you get an easy battery connector and 4 buttons with no soldering. 

This case has space for a LiPo battery, allows access to the USB-C slot and power slider, and printable buttons so your EE04 retains all its functionality!

Included STEP and Fusion 3D files for your tweaking pleasure. All attempts were made to model this parametrically for ease of editing.

Materials List

Product links to Amazon and Seeed are affiliate links; if you find this model useful and need supplies, I'd appreciate you buying through the link to support my efforts at no extra cost to you. I always link the exact items I used during the make so it goes together flawlessly!

Required components for the assembly

• Seeed Studio XIAO EE04 EPaper DIY Kit

  • Select either the 7.3" Spectra 6 display or 7.5" monochrome display. These tend to be backordered in the US warehouse. Mine shipped from China to US in under 2 weeks with the cheapest shipping tier. 

• (QTY 6) 20mm x 3mm neodymium magnets

• (QTY 4) M3 threaded heat set inserts, max 5.7mm height

• (QTY 4) M3 8mm flat head screws

• (QTY 4) M2 4mm self-tapping screws

• (QTY 1) 2000 mAh rechargeable LiPo battery w/ JST PH 2.0 connector

  • Without editing the model, up to 46mm (W) x 106mm (L) x 9.8mm (T) battery is supported

  • If going with a thicker battery than 6.5mm, be mindful of FPC routing, the 180 degree bendback may overlap the battery

• (QTY 1; optional but recommended at least for Spectra panel) Type B FPC cable

  • Type A cable included with the display requires a lateral twist (not enough vertical space in this case for that), 2x 45 degree folds which could damage the cable, or 2x 180 degree bends. Basically the 50 pin cable for the color display is much less malleable than the 24 pin, the one Seeed includes is likely too short to account for the extra rigidity, and I didn't want it to transfer stress to the panel connector. Using a Type B FPC cable allows connecting the EE04 and E-Ink display with a straight run and single 180 degree bend well within its minimum bend radius.

  • For 7.3" Spectra 6: 50 Pin, 0.5mm Pitch, Type B FPC Cable

  • For 7.5" monochrome if you have issues with included cable: 24 pin, 0.5mm Pitch, Type B FPC Cable

Required tools

• Appropriate size allen key for your M3 screws

• Phillips PH0 screwdriver for the M2 screws

• Multimeter

"Nice to have"

• Cyanoacrylate glue

• Kapton tape

Printing Instructions:

I used a 0.4mm nozzle with the 0.2mm quality profile in Prusaslicer. Everything used PLA. The following changes were made to the slicer settings:

• Bottom Shell:

  • Enable Supports --> Touching buildplate only

  • Scarf Joint --> Everywhere

  • PAUSE @ 3.4mm to insert 2-3 drops of cyanoacrylate glue and magnets

• Buttons:

  • 100% infill

  • Fun to print these in an accent color to add a bit of flair to your case!

• Lid:

  • Arrange the top surface facing the buildplate.

  • Hilbert Curve looks nice on the finished surface. If you want to do this, set the bottom fill pattern to Hilbert Curve and first layer speed to 15 mm/s.

Assembly Guide:

Test fit everything before attempting final assembly. The E-Ink panel is fragile, and the case is a very tight fit. If something doesn't seem right, don't force it. A good test is to turn the lid upside down and put your panel inside of it; it should drop right in yet be snug in the side-to-side direction. If this isn't the case, check your printer calibration.

1. Place the 4 buttons in their slots, tilting the case helps keep them all in.

2. Insert the EE04 on its standoffs in the recess. Secure it with four M2x4mm self-tapping screws. Do not use screws longer than 4mm without corresponding washers to offset any length over 4mm, otherwise the tips will stick through the rear of the case. Do not over-tighten the screws, the holes made by these tiny self-tappers are super easy to strip.

3. Install the antenna to the EE04, on the rear side of the USB-C charging component. It's a press fit; angle one side of the female connector onto the male and gently press the other side down. Route the wire off to the left and rest the antenna next to the EE04 cutout in the bottom corner.

4. Verify your battery polarity and note which wire is positive. Also note the orientation of the battery's JST PH 2.0 connector and how it will plug into the EE04's female connector. Make sure the + wire will be on the same side as the rail on the EE04 reading + behind the battery connector. These connectors are not standardized for polarity so you may have to swap the wires on your battery's connector to make sure it matches the EE04.

5. If you have it, use double-sided tape to secure the battery in the recess close to the case wall. Otherwise tape it down with kapton tape.

6. Heat your soldering iron to 250C. Sink the four M3 threaded heat-set inserts into the corner holes on the underside of the lid until they're flush or just below the surrounding surface.

7. Ignore and throw out the diagram Seeed includes in the EE04 static bag that shows the blue side of the FPC cable facing up when looking down at the EE04 board. This is wrong.

8. Loosen the tabs on the included FPC connector. The gold fingers on the panel's FPC, and the silver traces on the ribbon cable need to face the same direction. If you're looking at the rear of the panel with the FPC folded onto the rear, all pins are facing away from you. Gently bend the panel's FPC cable back towards the rear of the panel once the connector is mated to the ribbon cable and secure it in place with a piece of kapton tape. Place the panel into the lid as oriented below, with the FPC nearest to the shortest lip on the lid.

   

9. Plug the other end of the FPC cable into the EE04. The silver pins should be facing UP when looking down at the EE04 board. Type B FPC nicely bends back 180 degrees along itself when you close up the case.

   

10. I recommend bringing the case halves together at a similar angle to the below image. Make sure not to pinch your panel when lining up the case. Mate up the long face opposite the side with the buttons first and ensure the panel stays tight against this side of the case opposite the buttons.

    

11. Closing the case on the side with the EE04 buttons requires some finesse. What worked for me was using a couple fingers on top of the panel to gently slide the panel away from the buttons (ensuring it's fully seated against the opposite wall of the case), while with my other hand snagging the bezel of the lid with a fingernail and pulling it towards the buttons. This ensures the panel is out of the way and that the lid lip can slide past the bottom shell without crushing the panel.

12. Once everything is closed up tight, secure from the rear with your four M3 x 8mm screws.

Calendar Software

The software running on this is a simple stack:

• On my home server, a Python app containerized with Docker that pulls events from my family's self-hosted Radicale calendar, plus local weather data for the day, and generates the 800x480 color calendar image as a .bmp. The dithered color squares allow a pretty accurate match for our different color-coded calendars. Handling dithering server-side and generating a pixel-perfect image for the Spectra 6 display vastly simplifies the EE04 code.

• The .ino sketch on the EE04 fetches the .bmp from the server once per day over HTTP and draws it on the E-Ink display. It also measures the battery voltage and appends this to the fetch request to display a battery percentage in the corner. Finally, the EE04 also receives the number of seconds until its next scheduled daily refresh before anybody wakes up for the day, and goes to deep sleep to conserve battery until then.

Get the calendar rendering software and EE04 firmware along with setup guide here on GitHub.