3 ms·

For what its worth, my math was ~1 update per 15-minutes was the crossover point between memory-lcd and eink. There's a lot of different eink and memory-lcd sc

For what its worth, my math was ~1 update per 15-minutes was the crossover point between memory-lcd and eink. There's a lot of different eink and memory-lcd screens that could explain the difference between your calculation and mine. But all else considered, 15-minutes vs 60-minutes isn't much of a difference at all. For most applications of updates-per-second (or at worst, a few seconds per update), low-power monochrome seems best served by Sharp's memory-lcd.

kragen 4y ago
Agreed. Also, my figures for eink power consumption are very uncertain; possibly you were able to take measurements or get good datasheets, but I couldn't. A thing I didn't mention is that there are actually eink applications that have lower update rates than this. Store price tags, for example.
- dragontamer 4y ago
  I decided to try my math again and document it more carefully. -------- https://www.pervasivedisplays.com/wp-content/uploads/2021/12/1P255-00_03_E2154CS0C1_202111203doc.pdf https://www.pervasivedisplays.com/wp-content/uploads/2021/12... Pervasive Displays has an oscilloscope measurement of 3.75mA on their 5.9-second updates for their 1.54" eink screen. (Page 14). That's 22.125 mCoulombs of electrons. -------- https://media.digikey.com/pdf/Data%20Sheets/Sharp%20PDFs/LS013B7DH03_Spec.pdf https://media.digikey.com/pdf/Data%20Sheets/Sharp%20PDFs/LS0... Sharp 1.2" memory-LCD (a bit smaller) has 12uW to 50uW on static images. Assuming 3.3V, that's 15uA worst case (0.015mA). ------- 22.125 mCoulombs / 0.015mA == 1475 seconds per update break-even point, or ~24 minutes. So yet another number, but yeah, memory-LCD is just really good. Remember that the 1.2" screen from Sharp is a bit smaller though, so its not a perfect apples-to-apples comparison. Either way, its a much longer period between updates than I was expecting.
  - kragen 4y ago
    thank you very much! this is great!
  - Firmwarrior 4y ago
    Yeah man, thanks for this clarification, looks like I've been spending too much time tinkering with apps and I've gotten completely out of touch, haha

kragen 4y ago

Agreed. Also, my figures for eink power consumption are very uncertain; possibly you were able to take measurements or get good datasheets, but I couldn't. A thing I didn't mention is that there are actually eink applications that have lower update rates than this. Store price tags, for example.

dragontamer 4y ago
I decided to try my math again and document it more carefully. -------- https://www.pervasivedisplays.com/wp-content/uploads/2021/12/1P255-00_03_E2154CS0C1_202111203doc.pdf https://www.pervasivedisplays.com/wp-content/uploads/2021/12... Pervasive Displays has an oscilloscope measurement of 3.75mA on their 5.9-second updates for their 1.54" eink screen. (Page 14). That's 22.125 mCoulombs of electrons. -------- https://media.digikey.com/pdf/Data%20Sheets/Sharp%20PDFs/LS013B7DH03_Spec.pdf https://media.digikey.com/pdf/Data%20Sheets/Sharp%20PDFs/LS0... Sharp 1.2" memory-LCD (a bit smaller) has 12uW to 50uW on static images. Assuming 3.3V, that's 15uA worst case (0.015mA). ------- 22.125 mCoulombs / 0.015mA == 1475 seconds per update break-even point, or ~24 minutes. So yet another number, but yeah, memory-LCD is just really good. Remember that the 1.2" screen from Sharp is a bit smaller though, so its not a perfect apples-to-apples comparison. Either way, its a much longer period between updates than I was expecting.
- kragen 4y ago
  thank you very much! this is great!
- Firmwarrior 4y ago
  Yeah man, thanks for this clarification, looks like I've been spending too much time tinkering with apps and I've gotten completely out of touch, haha