os_smartwatch_v2

  • Time required: 20–40
  • Cost: $75–$125

My Open-Source SmartWatch combines readily available breakout boards, careful soldering, and a 3D-printed frame to make a one-of-a-kind timepiece that displays notifications from your smartphone and is easily customizable in function and appearance.

The watch design is straightforward, consisting of four major sections: a battery charging circuit, vibrating motor for silent alerts, programmable Arduino-compatible core with power regulation and Bluetooth LE, and an OLED display with pushbuttons.

Breadboarding the project is a snap. Wiring it into a small enclosure meant for the wrist is quite another matter. Break out your fine-point soldering iron and follow the complete instructions at oswatch.org.

schematic_battery

Battery Charging

A 3.7V 500mAh LiPo battery is wired to a JST connector and a two-position switch. Switched to the right, the circuit is in battery mode. Switched left, it’s ready for LiPo charging via the JST connector.

schematic_microduino_program

Programmable Core

Within the 3D-printed frame an 8MHz Microduino microcontroller is connected to a programming port, a Bluetooth Low Energy board for communicating with your smartphone or other devices, and a voltage regulating circuit.

schematic_motor

Vibrating Motor

The simple vibrator circuit consists of a diode, 1K and 33Ω resistors, capacitor, NPN transistor, and motor. The circuit is then connected to the Microduino to buzz your wrist when new calls or alerts come in.

schematic_buttons

Pushbuttons and OLED Display

Four momentary pushbutton switches are wired to three pull-up resistors internal to the Microduino and a single external 10K pull-down resistor.

schematic_screen_leds

An OLED screen and two small LEDs are wired directly to seven of the digital pins on the Microduino to display time, text, alerts, and more.

complete