Difference between revisions of "Watch display"

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** [https://www.adafruit.com/products/250 Graphic ST7565 Positive LCD (128x64) with RGB backlight + extras - ST7565] : Power: 3.0 V at 1 mA (when the 5.0 V at 120 mA backlight is off) (What exactly is the difference between this and the [https://www.adafruit.com/products/438 "Graphic ST7565 Negative LCD (128x64) with RGB backlight + extras - ST7565"]?)
 
** [https://www.adafruit.com/products/250 Graphic ST7565 Positive LCD (128x64) with RGB backlight + extras - ST7565] : Power: 3.0 V at 1 mA (when the 5.0 V at 120 mA backlight is off) (What exactly is the difference between this and the [https://www.adafruit.com/products/438 "Graphic ST7565 Negative LCD (128x64) with RGB backlight + extras - ST7565"]?)
 
** [https://www.adafruit.com/products/398 "RGB backlight positive LCD 16x2 + extras - black on RGB"] and [https://www.adafruit.com/products/399 "RGB backlight negative LCD 16x2 + extras - RGB on black"]. Is this really 2.7 V to 4.5 V at 0.3 mA ? (When R, G, and B LEDs are turned off).
 
** [https://www.adafruit.com/products/398 "RGB backlight positive LCD 16x2 + extras - black on RGB"] and [https://www.adafruit.com/products/399 "RGB backlight negative LCD 16x2 + extras - RGB on black"]. Is this really 2.7 V to 4.5 V at 0.3 mA ? (When R, G, and B LEDs are turned off).
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* Digikey has a long list of display modules at [http://www.digikey.com/product-search/en/optoelectronics/display-modules-lcd-oled-character-and-numeric/524437?stock=1 Digikey: LCD and OLED Character and Numeric Display Modules in stock] and also [http://www.digikey.com/product-search/en/optoelectronics/display-modules-lcd-oled-graphic/524918?stock=1 Digikey: LCD and OLED Graphic Display Modules in stock]. Which of them are low-power enough for an always-on wristwatch display?
 
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* ... ''Have you seen a display that would work on a wrist calculator? Please add it to the list here!'' ...
 
* ... ''Have you seen a display that would work on a wrist calculator? Please add it to the list here!'' ...

Latest revision as of 16:30, 6 December 2015

The display is perhaps the most critical part of a wrist computer such as the uWatch and the Open Source Watch.

The history of the uWatch mentions the 53mm x 20mm compact 16x2 line LCD that convinced David L. Jones that the uWatch project was actually doable with off-the-shelf components. If you are doing low-level programming of the uWatch, such as making "custom characters", you might want to look at the datasheet (via "Moon Phases").

Alas, that original display pulls about 2 mA, more power than anything else on the uWatch -- even the CPU uses less power (at 250 KHz). That's the main reason the current uWatch cannot run the display continuously (like a standard watch), but much be explicitly "turned on" every time you want to read the time.

The current uWatch2 rough draft seems likely to use the Newhaven NHD-C12832A1Z-FSW-FBW-3V3 128x32 Pixels display. Which uses less than 100uA which would enable a continuous display watch. The "white LED backlight" uses 30 mA at 3.0 V but is still very usable at much lower currents.

There's some discussion of some of the screens considered for the first iteration of the Open Source Watch at http://oswatch.org/details_screen.php .

Proposed displays: Limited to less than 10 mW of power when updating the time once a second (FIXME: reduce this limit and prune higher-power displays when this list gets too long): In no particular order:

Some threads discussing diplays: "Hardware Stuff » Why not a smaller LCD...",