tinkerish.com writes:
Do it yourself AVR atmega8 based GPS Running Watch. Consists of an atmega8 microcontroller, a LCD out of a Nokia 3310 cell phone, and a GPS module from SparkFun.com.
AVR Based GPS Running Watch – [Link]
Named ‘El Relojito’ (relojo = watch in spanish), this seemingly simple design is a great project for anyone ready to move past the rank of ‘amateur’. 60 LEDs surround the 7-segment leds telling you the time. A PIC micro controls all the action. The write-up is in spanish, but the schematic/pictures should be enough to guide you. [via]
Simple LED Clock PCB Design - [Link]
This watch is built around a 3V-powered ATmega328P running at 8MHz. Time is shown using 2 circles of 12 LEDs, in a manner similar to an analog watch (with hands). Minutes are indicated on the exterior circle of green LEDs; hours are indicated on the interior circle of red LEDs, as shown in this video.
Introducing DWex – Duino Watch for experimenters - [Link]

The uWatch is an open source RPN and Algebraic scientific calculator watch that you can build yourself. Jones writes: [via]
It only had an 18 key keypad, but I figured that was OK as my old CFX-400 only had 16 + 4 side keys. All the extra functions were performed with a MENU key and two rows of 4 soft function buttons that mapped to the 8 keys directly below the LCD.
uWatch : World’s First DIY Scientific Calculator Watch - [Link]
Two lights-emitting diode 5*8 matrixes where used to construct a computer controlled spectrum analyzer and clock. Microcontroller ATMEL AT90S2313 is the heart of device. The controllers accepts data from a serial port and with the help of conclusions of port B and the additional decoder 74145 is deduce a spectrum on the light-emitting diode screen are collected from two matrixes.
Spectrum analyzer + watch - [Link]





















