DIY Arduino UNO Programmable Watch Project

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Last week, we introduced a project about watches titled “I Made a New Watch for Myself This New Year!”.

This project is a programmable watch based on the Arduino UNO, which has a higher manufacturing threshold. At the same time, it is more mature and practical, and its design is very beautiful!

Let’s get into the main content!

This watch, only 10mm thick, can be used for several years and is powered by a CR2032 battery. It features a built-in DS3231 clock (RTC) chip, providing accurate time and temperature compensation.

Material List

Arduino Uno × 1
ATMega328 × 1
3V 20mm CR2032 Button Cell Battery × 1
0603 RED LED Diode × 12
DS3231 RTC Chip × 1

PCB Schematic and Layout

DIY Arduino UNO Programmable Watch Project

Create the PCB using Autodesk Eagle. First, import the parts library from the schematic, check the datasheet, and determine the correct logical connections. Then, I designed the layout of the PCB and generated the Gerber and Drill files.

The specific specifications of the PCB are: Layers: 2 Size: 35mm×35mm Thickness: 0.8mm Impedance: No PCB Color: Black Surface Treatment: Hot Air Leveling (Lead Included) Copper Weight: 1 oz Gold Finger: No Material Details: FR4 – Standard Tg 130-140C JLCPCB Group: No Flying Probe Test: Fully Tested Honeycomb Hole: No

Burning the Bootloader

If your ATmega328 (or ATmega168/88) is brand new, you need to burn the BootLoader first.

Without the initial code, the microcontroller cannot interpret the Arduino commands. It needs a bootloader, which is similar to the BIOS driver on a computer.

The bootloader must be burned before soldering. Please click this link for the steps: https://github.com/MCUdude/MiniCore#how-to-install

Details for burning the microcontroller are as follows:

Mainboard: ATmega328
Bootloader: Yes
Clock: Internal 1 MHz
Compiler LTO: Disabled
Variant: 328P/328PA
BOD: 1.8V

After successfully burning the Arduino bootloader to the ATmega328p, you can use the USB to serial converter (FTDI chip) on the Arduino board to upload programs.

Soldering and Assembly

The assembly process is very simple. Prepare all the materials and start from one side of the watch. For more details, please click on my website. https://mblazevic.com/iowatch-soldering-top

If you are new to soldering, it is recommended to refer to some tutorials on soldering 0603 components. https://www.sparkfun.com/tutorials/category/2

Programming

Using the FTDI test (connection) pads provided on the back of the PCB, you can upload code using a cheap FTDI converter.

I created a custom FTDI converter that utilizes the micro USB B interface on the watch PCB. Therefore, modifying and uploading code is very simple and convenient. Just remove the battery, connect the custom converter to the watch PCB, and program it.

For more detailed instructions on how to read the time, set the time, and read the temperature, please click this link. https://www.sparkfun.com/tutorials/category/2

3D Modeling and Printing

Designed in Fusion 360, what you see is the final version. Everything except the watch band and glass is 3D printed.

Specifically includes:

Watch Body
Watch Fixed Ring
Base
Button

Settings in Cura are as follows:

3D Printer: Prusa I3 MK3S
Material: PLA
Layer Height: 0.1mm
Shell Thickness: 0.8mm (Nozzle: 0.4-2)
Top/Bottom Thickness: 0.8mm
Fill Density: 100%
Filament: 1.75mm
Support Type: Any Type
Platform Adhesion Type: Skirt

The watch glass is press-fit, and the fixed ring on the body is also press-fit. Use M1.4 screws to secure the PCB to the bottom case, and then secure it to the inner body case. Don’t forget to place the 3D printed button.

Completion!

If you want to know more about assembly and soldering, you can visit the author’s website. https://mblazevic.com/project/iowatch

Original project link: https://www.instructables.com/Arduino-Wristwatch/

Project Author: Inge

Translation first published on Fun Unlimited

Reprinting is welcome, please indicate the source and author information

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If you have any thoughts or corrections regarding the article, feel free to leave amessage!

All files mentioned in the article can be obtained by replying “IO Watch” in the public account.

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