Arduino Watch




About: Make it yourself if you cannot buy one!

This Instructables show how to make a Arduino Watch from Arduino Watch Core.

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Step 1: Preparation

Arduino Dev Board

This time I am using Sparkfun Pro Micro 3.3 V 8 MHz dev board.

Watch Display

This time I am using a ST7789 1.3" IPS LCD.

Lipo Battery

I have some 301420 Lipo battery in hand.

Lipo Charge Board

I have some 15 mm x 15 mm Lipo charge board in hand.

RTC Chip

This time I am using DS3231M, it built-in crystal oscillator, no extra component required

RTC Battery

This is optional, in case you want to keep the time even Lipo battery used up. MS412FE is a tiny 1 mAh rechargeable battery, according to the RTC datasheet 1 mAh already can keep time many days.

Watch Strap

I have ordered some 20 mm width fabric canvas watch strap.


A diode e.g. 1N5822, four 6 mm M2 screws, copper foil tape and some wires

Step 2: Fixing Dev Board & LCD

Use a small piece of PET plate to stick the Pro Micro and IPS LCD together.

Step 3: Connect GND

Read the LCD datasheet provided by your vendor.

Cut a little copper foil tape just touch all GND pins and LED negative pins and fix it on the FPC plate. Then soldering the pins with copper foil tape.

Step 4: Connect Power Pins

Connect dev board GND Pins to the copper foil tape. Connect Vcc pins to LCD Vcc pin.

Step 5: Connect LCD Pins

Here are the connection summary:

LCD  -> Arduino
LED+ -> GPIO 10
RST  -> GPIO 18(A0)
DC   -> GPIO 19(A1)
CS   -> GPIO 20(A2)

Step 6: Remove Power Led

The power LED always on and consume over 1 mA continuously, so it is better remove it. Unsoldering and remove the LED carefully.

Step 7: Connect Lipo Battery

Here are the connection summary:

Charge Board +ve in      -> Dev Board J1 connector near the USB socket (5V)
Charge Board -ve in      -> Dev Board GND Pin
Charge Board Battery +ve -> Lipo +ve -> 1N5822 diode -> Dev Board Raw Pin
Charge Board Battery -ve -> Lipo -ve


Most Lipo charge board is better use 5V power as input. However, Pro Micro dev board do not provide USB 5V pin. Fortunately, the J1 connector near the USB socket is actually connected to USB 5V pin. Beware not soldering 2 connectors together.

Step 8: Connect RTC

DS3231M is very tiny and it require to connect to a tiny battery, please be patient connect all together:

DS3231M pin 2 (Vcc)  -> dev board Vcc
DS3231M pin 5 (GND)  -> dev board GND, MS412FE RTC battery -ve
DS3231M pin 6 (VBAT) -> MS412FE RTC battery +ve
DS3231M pin 7 (SDA)  -> dev board GPIO 2 (SDA)
DS3231M pin 8 (SCL)  -> dev board GPIO 3 (SCL)

Step 9: Connect Motion Sensor

As mentioned in my previous instructables, I use 2 vibration sensors as a motion sensor to trigger the dev board wake up pin.

However, the watch have no room to fit 2 5 mm vibration sensors. I have tried replace with a 3 mm vibration sensor and tested few days. It is too easy mis-triggered wake up and the battery drain up within a day.

I am still testing some other methods to avoid mis-triggered wake up. you may follow my Twitter to get the latest findings.

Step 10: Program

Please follow my previous instructables to program the dev board.

Step 11: 3D Print Watch Case

Please download and print the watch case:

Step 12: Happy Time!

It's to show off what you have done to your friends!

And also you can:

  • program and design your own watch face
  • add more sensors or components to make it become a smart watch
  • design your own watch case

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    11 Discussions


    Question 3 days ago

    Where is the pin 15 and 16 in arduino pro mini?????

    1 answer

    Answer 3 days ago

    Pin 15 and 16 are Pro Micro SPI SCK and MOSI pins representatively. If you use Pro Mini, the SPI SCK and MOSI pins should be 13 and 11.


    24 days ago

    I do like the tiny rechargeable backup battery. I've never seen them before and this seems like the ideal application for it!


    4 weeks ago

    How long does the battery last and does it charge through the USB port?

    2 replies

    Reply 4 weeks ago

    It can last around 1 week, depends on how many times motion sensor triggered wake up.


    Reply 4 weeks ago

    Have you looked at paper white displays? If so, what was your opinion of them for this type of application?


    4 weeks ago

    Very nice and compact. Good job!


    5 weeks ago

    is there a way to put gifs on it? that would be awesome.

    1 reply

    Reply 5 weeks ago

    I will try other watch face at next Instructables, the bitmap may be raw, GIF or JPEG, depends on processor power.


    Question 5 weeks ago

    Have you considered adding Bluetooth to it?

    1 answer

    Reply 5 weeks ago

    Yes, I am considered BT, WiFi, GPS, 9 axis sensor, heart beat sensor and more...