Fashionably on Task: a Smart Bracelet for Forgetfulness

Wearable Workflow: A Sculptural ePaper To‑Do Bracelet

Are you ready to wear your productivity on your sleeve—literally? Welcome to a project that proves jewellery can be as smart and functional as it is stunning!

Created as a collaborative project for the Instructables Jewellery Competition (always motivated by these competitions!), this tutorial will show you how to build a Wi-Fi-enabled, tri-color ePaper to-do list bracelet.

Inspired by the incredible freeform circuit sculptures, we’re ditching traditional circuits. Instead, we are using raw brass bars and enameled wire to create a beautiful, exposed structural frame that doubles as our ground plane.

Whether you're a seasoned maker or a jewelry designer looking to add some serious high-tech flair to your wearable art, this project will spark your creativity. Let's fire up the soldering iron and make some functional fashion!

[This is the first collaboration I've put on Instructables working with my husband. He has the CAD skills, the ability to create more intricate designs with the soldering, and the patience for it! Using both our skill sets has created this artwork jewellery piece.]

Before we dive into the build, let's round up our parts. We need a mix of traditional jewellery/metalworking supplies and some modern micro-electronics.

The Electronics:

1. ESP32-C3 Super Mini microcontroller (We used a super cool pink one!)
2. Tri-colour ePaper display
3. Lithium rechargeable battery
4. Battery charge board
5. Micro on/off switch
6. Enamelled magnet wire (Two gauges: slightly thicker for Power/Ground, slightly thinner for Data/Clock lines)

The Hardware & Tools:

1. Brass bar stock (for the main structural frame) choose weights to suit your project
2. MDF block (for creating our soldering jig)
3. Soldering iron & flux (See our pro-tip in Step 3 about using a jeweller's torch!)
4. Fusion 360 (for CAD design)
5. PlatformIO (for programming)
6. Roland MXT-40A CNC Mill (or similar router/mill to cut the jig)

We are using an ESP32-based board so that we can use wifi in our completed jewellery piece. We will be connecting to our mobile phone to create a 5-item to-do list that we can edit on the fly!

Note: PlatformIO is used with VisualStudio - but you can use ArduinoIDE if that is your preference.

You will need soldering skills to make this, and if you design it in CAD first you will need the software skills for that too.

For a quick reference, here is the basic workflow and requirement list to pull this off:

What You Need:

1. Tech: ESP32-C3, Tri-color ePaper display, battery, charge board, switch.
2. Materials: Brass bar stock, MDF block, two gauges of enamelled wire.
3. Software/Machinery: Fusion 360, PlatformIO, CNC Mill (like the Roland MXT-40A).

The Workflow:

1. Design: Measure wrist, model components in Fusion 360.
2. Jig Creation: Mill the 3D negative space into an MDF block to hold components.
3. Frame: Bend brass, place in jig, solder USB connector to frame to create a structural ground plane. (Watch out for thermal mass—use a jeweller's torch if possible!).
4. Wiring: Use enamelled wire (to prevent shorting on the ground plane) to connect all data and power lines in a visually pleasing, freeform style.
5. Code: Flash the ESP32 via PlatformIO. Configure the web-server UI, deep-sleep mode, and IO0 wake button.
6. Use: Connect via phone to update your tri-colour to-do list!

Because this is a wearable piece, comfort and fit are key. First, measure the wrist to ensure the brass frame will sit perfectly.

Using those measurements and the physical dimensions of our electronic components, design a CAD model (ours using Fusion 360) to visualize the design. This wasn't just to see how it looked—this 3D model also gives us the exact dimensions needed to cut our materials.

To keep everything perfectly symmetrical and aligned during the tricky freeform soldering process, I used the 3D design to generate toolpaths. From this, you could mill a custom pocketed shape into a block of MDF. This MDF block acts as our ultimate soldering jig, holding every component in the exact right place for both sides of the bracelet.

Here is where the magic happens! Bend the brass bars to match your wrist design and place them into the custom MDF jig.

To keep the design incredibly clean, the brass frame itself acts as the common ground plane* for the whole circuit.

Because there is no mounting spot on many of these electronic modules, the only solid point to connect the brass rod to something with thermal connectivity, is essentially the USB connector. To attach the connector and the brass bar - you will need to melt the solder between them.

1. The first connection we will create is to solder the USB connector directly to the brass frame.
2. An essential step is to pre-tin the USB connector (this means add some solder to it), then heat the brass bar up to the point where it will take the solder, then don't let it cool down - have the USB ready to put on the top of it, and drag the solder iron along. Essentially this is to reflow the solder.
3. The trick to makeing it look reasonably neat, is to control where you put your flux!

⚠️ Maker Pro-Tip: Brass has a massive thermal mass! When using a standard soldering iron, heating up the bar to add a new component would sometimes desolder the parts we had just attached. It was a delicate balancing act! If we were to build version 2.0, we would highly recommend using a jeweller's torch to join the main frame together or utilizing slightly thinner brass wire to reduce the heat transfer.

You can reuse your jig which is a great perk!

*What's a ground plane?

A ground plane is a large area of copper on a PCB that serves as the common reference point (0V) for the entire circuit. Instead of running individual ground traces everywhere, you give signals a big, low‑impedance “sheet” of copper to return through.

Think of it as the quiet, stable floor your whole circuit stands on.

Because the entire brass frame is an active ground plane, we couldn't just use bare metal wire for the rest of our connections, or the whole bracelet would short out! Eek!

This is where the enamelled wire comes in. The invisible enamel coating allowed us to coil the wires beautifully around the brass bars for physical support without making an electrical connection. We used a slightly thicker gauge wire for our power routing and a thinner, more delicate wire for the data and clock lines.

Take your time here.

Routing the wires beautifully is what gives freeform electronics that magical, architectural look! Connect up your:

1. charge board,
2. battery,
3. on/off switch,
4. ePaper display,
5. and that pink ESP32-C3 (or ESP32 of your choice.

Don't forget to stop and admire your work!

With the hardware looking like a piece of cyberpunk art, it’s time to give it a brain. We programmed the ESP32-C3 using PlatformIO. Note that the code will work if you are using the Arduino IDE as well.

What the jewellery will do:

When powered on, there are 2 options:

1. the bracelet connects to your wifi that you have entered in the name and password for, or if it can't find or connect to your wifi...
2. the bracelet broadcasts its own Wi-Fi Access Point. You simply connect to it with your smartphone, which automatically opens a custom web page.

From this UI, you can:

1. Type out your top 5 daily To-Dos.
2. Change the background and text colors (taking full advantage of that tri-color ePaper display!).
3. Mark tasks as complete.
4. Remove/Reset all tasks

To save battery, the ESP32 is programmed with a deep sleep mode. What is amazing is that the ePaper screen continues to display your list using zero power. When you need to update your list, just press the IO 0 button on the microcontroller board to wake it right back up!

I wrote the code using Visual Studio and PlatformIO. This creates a .cpp file that will be uploaded to the ESP32. To use this for the Arduino IDE, you can create a new sketch in Arduino, and copy the code from gitHub, then paste the code into your sketch in the Arduino program.

Be aware of the libraries that this project will need.

NOTE: I made a video https://youtu.be/Ww5av-e-W50 that demonstrates connecting an ePaper screen with an ESP32 dev board, as well as how to make the image file to use in your program.

Pin mapping for ESP32-C3 Mini

The pin mapping will change if you are using a different device. This is one thing you will need to edit in the code but it it at the top of the code so it's easy to find.

The line at the bottom is for the tri colour ePaper screen, the line of code commented out is for a B&W device.

Change the SSID and Password to match your system to use it in wifi mode. If it can not find the Wi-Fi, then it will use AP mode, where, essentially, it is creating its own server for you to connect to to talk to the device.

You can change these values to anything!

The other thing that is quite fun about the code is that there is an area that is all HTML for displaying the webpage. You can go into this code and edit it to display different words, or have a different background colour and so on. You can really customize this!

For example, these are some of the styles that control how the page will look:

The full code is available on GitHub: https://github.com/cmoz/YouTube/tree/main/BrassToDoWrist

Switch it on, sync your tasks, and strap it to your wrist.

You now have a completely custom, highly functional piece of electronic jewellery that is guaranteed to start conversations wherever you go.

[Supporting tutorial YouTube video on its way!]

Learning about wearable technology? Join me in my journey!

💜 Make fun wearable tech projects with me! Do you want to learn more tips and tricks for creating wearable technology? https://www.youtube.com/@CMozMaker

➡️ Dive into more fun projects with Arduino and ESP32 by exploring my playlist.

➡️ Additionally, for wearable technology items, such as conductive fabrics, visit my little maker shop Tinker Tailor.

✔️ My book on Amazon about making wearable technology.

➡️ Or for other projects and information, see my site: https://christinefarion.com