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Initial design thinking

A project log for ePaper clock

Compact low power epaper clock using a msp430

Waldo WolmaransWaldo Wolmarans 09/25/2019 at 09:330 Comments

I got a couple of e-paper displays to try out from waveshare .  

Why a clock?

I did start making a picture a day fridge magnet 2.7 display  (will come later).  But a clock is a good practical use case for e-paper because of the good view angles and low power.

Witch display?

Picking the right display can be tricky. Size, resolution and colors is not the only constraints.  Refresh time and partial updating is very important . I did not want to go the writs watch way. A small compact desk / table clock will be nice .  You can see the time easy with your corner of your eye.  The 2.13 inch display looks good. Black and white is better higher res and can do partial updating , where the 3 color can't. 

Main chip

Must be low power.  I had a couple of LaunchPad boards and the msp430 is known for low power use.

Power source

I did not want to go the lipo route. Lipo needs extra circuitry and is a shipment  problem these days. CR2032 coin cells (3 V) are easy to get and cheap. The msp430 can easily work with coin cells. And testing with the displays looked like it can works down to 2.8 V

Extra storage

A extra flush chip can hold lots of image fonts . SD cards don't work to well because it use to match power and need 3.3v

Display driver

The e-paper displays require external circuitry to work.  Mostly for boosting the voltage to do the e-ink magic.

Software

The msp430 does have a Arduino like environment you can use called  energia . Make it easy to port Arduino code find on the internet. 

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