|µWatch2 Back Again|
Message #1 Posted by DaveJ on 20 Aug 2011, 9:26 a.m.
Well, it's been around 2 years wince I last floated ideas for my µWatch2 project. Lots of things have happened since then which left zero time and enthusiasm for it, but as with all my projects it's back again.
This time it has a new concept and a new look, which I really like and think will work much better than any previous designs.
It is designed to be a "clip-in" watch calc, so it works equally well as a calc watch, or a tiny pocket calc. Just snap it in and out of the rubber watch band.
- 168x144 mono LCD. No backlight yet, it's designed for very low light conditions. But maybe I can add an even backlight as the LCD is transflective.
- 41mm x 55mm x 10mm alloy or SS case with screw on back plate
- 20 key keypad, with recessed legend overlay. 100g tact switches. 6.5mm key spacing
- Powered from 2 coin cell batteries. (estimate 1+ year life with continuous display)
- Processor choice is up in the air. Suggestions? Needs to be low power, I want to run continuously at 32KHz. Microchip 24F XLP perhaps. Would shoot for say 64KB & 8KB minimum as per the Mk1 uWatch. If it could play chess again I'd be happy.
The LCD and keys are FIRM, and the case design is almost complete to fit actual hardware. According to eMachineShop it should be manufacturable.
First design was 60mm wide with an extra column of keys, but I thought this was too big.
The concept is not a super high end feature watch, with USB and all sorts of fancy stuff. The idea is now low power, long battery life, ruugged, good nerdy calc watch looks, functional, with a basic Casio CFX-400 style shifting key style calc interface.
Might even have an internal micro SD card for storage, maybe
It will have a mineral glass protection for the LCD. Though I'm not sure how these are best mounted. At present it will just sit inside the case against the LCD. If it can some how be glued(?) on a front recess or something then I'll do that.
It will have a 0.1" I/O header pin interface on the left side, for, whatever...
Been thinking about a temperature compensated crystal for a super accurate watch, but that would increase the consumption maybe 10 fold.
Cost is not really factoring into the design, I want this to be a proper commercial quality calc watch you can wear everywhere and have it look good and last.
Buttons and spacing are designed so you can actually use the thing.
Previous designs have gone for powerful 32bit micros, rechargable lithium ion batteries, touch screen or cap sense buttons, and USB etc. But touch screen watches are now a dime a dozen, and I think cap sense will just be too variable at a small key spacing.
I want something with real calc buttons that screams "I'm a NERD!"
It is designed to fit the massively popular existing iPod Nano TikTok watch band. So it's the exact same height as a nano (41mm), but longer, so it would simply hang over each side of the watch band.
As always, feedback welcome.
Edited: 20 Aug 2011, 9:55 a.m.