I've always loved watches; not only are they aesthetic and beautiful, but they are functional, precise and useful. An elegant fusion between engineering and art; two normally opposed perspectives, now joined in harmonic unison. However, all technologies like the dial-up internet, the CVT monitor and the abacus, inevitably will become relics of our past with the advent of advancing technology, and have since become less pragmatic for the typical person to own. Unlike these archaic technologies, the wrist watch still thrives on the wrists of many, standing forever as a testament to one of mankind's greatest inventions: the measurement of time.
I suppose it was inevitable that I would design my very own wrist watch. The name for this wrist watch is the ChronosMEGA, a combination the greek word: chronos for time, and MEGA for the ATmega328P processor used.
The below video is a montage that saturates 4 months of development in 4 minutes.
This short video demonstrates the features of the watch and briefly explains how it functions:
- Robust and practical for daily use; long battery life
- "Production ready" and professional; to look, feel and behave like a finished product
- Compact, small form factor
- Assembly SW to drive the system
- To be as aesthetic as possible
- Atmel ATmega328P QFP processor
- Binary time encoding using 10 Blue 1206 LEDs
- Buttons to control time, sleep mode and display
- 32.768kHz external crystal and 8MHz internal clock source
- Micro-USB and Charge Management Controller to recharge 400mAh Li-ion battery
- Draws 4uA in its Deep Sleep mode to last up to 11 years on a single charge (see section 5.3.)
- Battery Indicator 0603 LED
- Boost TI Switching Regulator for power regulation
- Low Loss PowerPath Controller IC for power source selection
- Total form factor of 10mm x 40mm x 53mm
- Custom 3D designed case cast in pure polished silver
- Genuine crocodile leather watch band
This Instructable will be broken into two big sections:
I.1.1. Section 1: The Design; the Development
This section will introduce my approach and design considerations, and then dive into each component: explaining in great detail how the ChronosMEGA was constructed from top to bottom. There is even a pre-requisites page for a friendly pointer to what topics you must understand so you may understand the topics covered here.
I.1.2. Section 2: The Cloning Process
All files are included in this Instructable so you can build a ChronosMEGA clone with virtually no work on your part. There is a .zip file below on this page with everything you need, including:
• Gerber files to send directly to a board manufacturer
• STL files to send to a 3D printer
• Assembly ASM files to upload directly to the MCU
• Bill of Materials with links to every single part purchased
In this section, I provide step-by-step instructions with plenty of pictures to guide you in cloning. The process will cost you approximately $100 to $700 depending on the options you choose. The largest factor in price is the case material you choose.