Creating a Smartwatch with 200 LEDs: A Cool Open Source Project

Recently, while browsing Hackaday, I came across a really cool smartwatch project that is still in development, and I want to share it with you.

Background

The author is building this ESP32 Pico Watch, which features WIFI, BT, Mesh, a vibration motor, an RTC, 4 buttons, a USB-C connector, and most importantly: 192 LEDs. You can control the 192 LEDs on the watch to create complex lighting effects.

There are a total of 4 rings of LEDs. The outermost ring is the second hand, which will be white. The two middle rings are purple, representing minutes. The innermost ring is yellow, representing hours.

The LED driver is an IS31FL3733-TQ.

The inspiration for the watch comes from the Japanese brand TokyoFlash®.

The author hopes to create a fully modern connected watch that can communicate with our phones or any other IoT devices.

What can this watch do?

The design of the 603-200 Morphwatch® aims to create a stunning visual effect using 192 LEDs. It consists of 4 rings of 603-sized SMD colored LEDs.

• 1 outer ring made of 60 white 603 LEDs for the second hand.
• 2 middle rings of purple 603 LEDs to display minutes.
• 1 inner ring of yellow 603 LEDs representing hours.

Each LED can be programmed independently using the I2C library or through Python scripts.

In terms of visual effects, users can unleash their creativity to the fullest.

Apart from visual effects, this watch has many other functionalities due to its powerful Espressif® ESP32 PICO D4 chip.

It can interact with your phone via Bluetooth. Through the phone, you can use the watch to enter a private MESH wireless digital network for communication.

You can make your watch vibrate when your phone is out of range (via Bluetooth) or far away (via WIFI).

With 4 buttons, you can design your watch to trigger various actions, such as sending emergency emails, sending vibration messages to another watch, etc.

Using the MESH ESPNow protocol, each watch can communicate with another watch, sometimes over distances of hundreds of meters; you can establish your private long-distance communication system beyond cellular networks.

You can also switch your watch into an access point or a web server, allowing anyone to connect and retrieve information (like a business card concept…).

Of course, it has the most important function: telling the time.

Related Documents

Since this watch is open source, everyone can access all related documents.

Main Content

We want to create a hybrid concept of a retro LED watch + a connected watch. We naturally thought of the ESP32 PICO D4 chip, which is powerful and has the classic 603 LEDs. If this version is successful, we plan to move the 603 LED package to 402 and reduce the diameter of the watch, making it more suitable for women to wear.

With a set of 192 LEDs driven by the classic IS31FL3733-TQ chip, we can achieve a series of very cool visual effects, as each individual LED can be independently controlled via I2C, allowing us to unleash our creativity in designing the desired effects.

ESP32 PICO 4D connects the watch with WIFI/BT and most importantly ESPNOW, enabling us to create a community MESH network.

If there are enough watches, we even envision establishing a global communication network beyond the existing commercial locked communication networks.

The first concept was created using SolidWorks. This is a cool software that can evaluate various possibilities and test various graphic options.

▼ Click to view

PCB Motherboard

Classic modules:

• Lithium battery charger module
• ESP32 PICO D4 to drive the system
• DS3231MZ real-time clock
• A CP2104 to convert USB to ESP32 readable signals
• A ME6211C33M5G-N 5v/BAT to 3.3v voltage regulator
• A TP4054 for charging

In this project, we need to frequently check the battery status. The ESP32 Pico D4 will read the battery status from (ADC).

This first PCB board will send power and I2C signals to the sister board that holds the LEDs and LED drivers. This way, we can easily design various different sister boards.

The motherboard has plugs and buttons to select various functions.

The WIFI/BT antenna is a PCB antenna. We plan to provide options for RFM95 _868/915MHZ in the next version. We need to work on handling two different antennas.

The USB connector for charging and uploading Arduino IDE sketches will be a USB-C port.

PCB Sister Board

The second part of this concept is to have a sister board that will accommodate 192 LEDs. A set of 3 connectors will send power and signals from the main board to the sister board.

We found it interesting to use this type of connector, as it allows maker friends to easily redesign a sister board with their own designs and creativity (adding a true color display, making different LED patterns, adding micro motors with complex functions, etc.).

Having a second board is also a good way to sandwich the battery in between.

The LED sister board is pluggable. The design concept of this watch is that the wearer can unscrew the screws on the watch to tinker with the components inside.

Aside from the LEDs, only one IC is used, which is an IS31FL3733-TQ, accepting the IC2 protocol and capable of driving up to 192 LEDs organized in a matrix style.

It offers a cool 56mm diameter PCB (more suitable for men and RAP singers). Once the prototype passes functional testing, we will move the 603 package to 402 and reduce the diameter to 40mm, making it more suitable for women.

After hours of struggling to design a 2-layer PCB without success, this will be a 4-layer PCB.

This is the current progress of the watch. If you want to be updated on the latest developments, feel free to follow this project on GitHub!

Project link: https://github.com/ccadic/The603-200