5 ms·

I'd like a smaller one in my home that I could interact with programmatically. Something that could hold weather forecasts, family calendar events, reminders, p

I'd like a smaller one in my home that I could interact with programmatically. Something that could hold weather forecasts, family calendar events, reminders, pictures, etc. I like the matte look of e-ink.

deleted 2y ago
[deleted]
chainwax 2y ago
https://usetrmnl.com/ https://usetrmnl.com/ This was recently shared here on HN: https://news.ycombinator.com/item?id=42137513 https://news.ycombinator.com/item?id=42137513
- whamlastxmas 2y ago
  I own 5 of them and love them!
- m463 2y ago
  Can you point these at your own server instead of theirs?
  - jwithington 2y ago
    Yes https://docs.usetrmnl.com/go/diy/byos https://docs.usetrmnl.com/go/diy/byos
sho_hn 2y ago
Here's the one I built for my home: https://imgur.com/a/NoTr8XX https://imgur.com/a/NoTr8XX This is still a black and white panel, but it's not that different with the color ones. Feel free to reach out if you have questions.
- generj 2y ago
  How was your battery life performance? I’ve been (slowly) working on a similar project and it’s been easy to get it running on my desk hooked into power but much more difficult to elegantly frame the panel that can just live on a wall.
  - sho_hn 2y ago
    I ended up replacing the battery with a larger one than the one pictured in the end, a 3100 (ed: hang on, was it maybe 3500 even?) mAh Samsung 18650 cell. I also switched the voltage reg to a more efficient chip. I now get about 9-10 months on a charge (with one daily refresh over wifi) in practice. At those durations battery Li-Ion self-discharge is actually a big factor sadly so a lot of those mAh fade into the ether. :)
    - blkhawk 2y ago
      I made my own version of this and I am seeing a lot of interesting choices so I am intrigued. The lack of soldering means you probably don't do that normally. I find it wild that you used a dev board because the LDOs on them are most of the time very bad and you do seem to use 5V instead of bypassing that. The type you get normally uses 1mA just sitting idle. Why did you use an external RTC instead of just soldering a 32.768khz crystal to the esp32? Okay if my assumption above is correct that answers that. but the external wakeup has no real advantage in power draw. The relay eats some current and a mosfet in its place would probably be better. I assume you added it because the e-ink hat has no proper shutdown. From the looks of it you can just bypass the BUCK converter on it so just run it off 3.3-3.6v. There is a smaller BOOST converter in there that might still waste power so the mosfet might still be needed. This beings me to my next point: you can completely do away with the DCDC boost converter by using a LiFEPO4 battery. All you need extra is monitor the voltage and have your display warn once it falls below 3V. Anyway 9-10 months is remarkable for the LEGO approach.
      - sho_hn 2y ago
        > but the external wakeup has no real advantage in power draw. This particular external RTC has very low power draw, and it allows me to put the esp32 into a deeper sleep state and turn off the entire RTC and RTC memory mini-MCU in the entire esp32. It does make a difference. > I assume you added it because the e-ink hat has no proper shutdown. From the looks of it you can just bypass the BUCK converter on it so just run it off 3.3-3.6v. There is a smaller BOOST converter in there that might still waste power so the mosfet might still be n Aye, the controller board isn't designed for a battery-based application and has an idiotically high idle power draw, even not taking the always-on power LED into account I could have taken out, so I'm only powering it up to do the update. And yeah, I'm sure a MOSFET would do this fine. > Anyway 9-10 months is remarkable for the LEGO approach. The LEGO approach is partly because I kept shifting the goal posts - originally I wanted to forego controller board entirely, and directly drive the e-ink waveforms from the MCU with the help of an op-amp (there's some prior art and reverse engineering available for this). This is partially why I picked a dev board with a big external PSRAM for a trial run. The controller board has its own SPI memory to hold the large framebuffer, but I was originally going to park this with the esp32 and have the lob of memory hooked up there :-) My other plan was actually ordering a custom PCB that has it all in one place (this is the main reason why I didn't bother to solder anything to a perf board). But then I had a little daughter and plans changed, so I shipped the mockup to production. Since it's holding up pretty well I'm quite happy with how it turned out anyway, but I absolutely agree a cleaned-up "v1.0" of this thing would be really nice to do at some point. Also, do note that I'm mainly a software engineer and have no formal training or background in EE, so partly I do these as little hobbyist learning projects and to do something with my hands. If your day consists of Alt-Tabbing between your EDA and your Mouser/Digikey order tracking I'm sure you'd approach this very differently and iterate it much more on the screen first :)
- StevenNunez 2y ago
  This is so cool! I always dream of doing this but don't know where to start. Even using old LCDs for new and interesting form factors would be a dream. Nice work on this!
  - sho_hn 2y ago
    Thanks! The main difficulty & goal with this one was reducing the power consumption to the absolute minimum, which meant putting some effort into component choices and I also ended up writing the display controller driver myself. But if you just want to get going, you don't really need to go through that sort of trouble. You can just buy a panel + controller board via a retailer like e.g. Waveshare, and hook them up to a computer. Quite a few of these controller boards even have HDMI input, or come with SDK code for e.g. Raspberry Pi if they use SPI over GPIO. You can tinker quite a bit without things getting more challenging, and if you can arrange for wired power you may not really need to optimize anything.
- fosh 2y ago
  This is so polished! Have you shared the latex / other bits anywhere ?
deleted 2y ago
[deleted]
brian-armstrong 2y ago
There's Visionect if you want to go large enough to see on the wall at a glance (32") https://www.visionect.com/shop/place-play-32/ https://www.visionect.com/shop/place-play-32/
- xienze 2y ago
  Perhaps a requirement left unsaid by OP, but something reasonably priced. $2500 is a bit rich for what it would be used for.
  - brian-armstrong 2y ago
    $2500 isn't too far off of the BOM for epaper this large, plus some markup for the assembler. Even if you bought this as a bare panel and a battery on Alibaba, you're not going to do better than $1500 or so. At current date that's just what it costs
- grogenaut 2y ago
  it's just absurdly priced though when you compare with a 80"+ tv, I get it, its different lower volume tech, but chicken and egg.
  - rbanffy 2y ago
    Indeed. This is the issue with these panels. They tend to be prohibitively expensive. Worth for signage because labour costs will dominate in the long run. I suspect this is what dictates the panel prices.
jwithington 2y ago
Trmnl was referenced but also this one https://learn.pimoroni.com/article/getting-started-with-badger-2040 https://learn.pimoroni.com/article/getting-started-with-badg...
bitdivision 2y ago
https://www.waveshare.com/product/13.3inch-e-paper-hat-plus-e.htm https://www.waveshare.com/product/13.3inch-e-paper-hat-plus-... The spectra color displays seem to be available cheaper than I expected ($250). Note that the refresh cycle is really long on these though. I'm now tempted to put something together.

deleted 2y ago

[deleted]

chainwax 2y ago

https://usetrmnl.com/ https://usetrmnl.com/ This was recently shared here on HN: https://news.ycombinator.com/item?id=42137513 https://news.ycombinator.com/item?id=42137513

whamlastxmas 2y ago
I own 5 of them and love them!
m463 2y ago
Can you point these at your own server instead of theirs?
- jwithington 2y ago
  Yes https://docs.usetrmnl.com/go/diy/byos https://docs.usetrmnl.com/go/diy/byos

sho_hn 2y ago

Here's the one I built for my home: https://imgur.com/a/NoTr8XX https://imgur.com/a/NoTr8XX This is still a black and white panel, but it's not that different with the color ones. Feel free to reach out if you have questions.

generj 2y ago
How was your battery life performance? I’ve been (slowly) working on a similar project and it’s been easy to get it running on my desk hooked into power but much more difficult to elegantly frame the panel that can just live on a wall.
- sho_hn 2y ago
  I ended up replacing the battery with a larger one than the one pictured in the end, a 3100 (ed: hang on, was it maybe 3500 even?) mAh Samsung 18650 cell. I also switched the voltage reg to a more efficient chip. I now get about 9-10 months on a charge (with one daily refresh over wifi) in practice. At those durations battery Li-Ion self-discharge is actually a big factor sadly so a lot of those mAh fade into the ether. :)
  - blkhawk 2y ago
    I made my own version of this and I am seeing a lot of interesting choices so I am intrigued. The lack of soldering means you probably don't do that normally. I find it wild that you used a dev board because the LDOs on them are most of the time very bad and you do seem to use 5V instead of bypassing that. The type you get normally uses 1mA just sitting idle. Why did you use an external RTC instead of just soldering a 32.768khz crystal to the esp32? Okay if my assumption above is correct that answers that. but the external wakeup has no real advantage in power draw. The relay eats some current and a mosfet in its place would probably be better. I assume you added it because the e-ink hat has no proper shutdown. From the looks of it you can just bypass the BUCK converter on it so just run it off 3.3-3.6v. There is a smaller BOOST converter in there that might still waste power so the mosfet might still be needed. This beings me to my next point: you can completely do away with the DCDC boost converter by using a LiFEPO4 battery. All you need extra is monitor the voltage and have your display warn once it falls below 3V. Anyway 9-10 months is remarkable for the LEGO approach.
    - sho_hn 2y ago
      > but the external wakeup has no real advantage in power draw. This particular external RTC has very low power draw, and it allows me to put the esp32 into a deeper sleep state and turn off the entire RTC and RTC memory mini-MCU in the entire esp32. It does make a difference. > I assume you added it because the e-ink hat has no proper shutdown. From the looks of it you can just bypass the BUCK converter on it so just run it off 3.3-3.6v. There is a smaller BOOST converter in there that might still waste power so the mosfet might still be n Aye, the controller board isn't designed for a battery-based application and has an idiotically high idle power draw, even not taking the always-on power LED into account I could have taken out, so I'm only powering it up to do the update. And yeah, I'm sure a MOSFET would do this fine. > Anyway 9-10 months is remarkable for the LEGO approach. The LEGO approach is partly because I kept shifting the goal posts - originally I wanted to forego controller board entirely, and directly drive the e-ink waveforms from the MCU with the help of an op-amp (there's some prior art and reverse engineering available for this). This is partially why I picked a dev board with a big external PSRAM for a trial run. The controller board has its own SPI memory to hold the large framebuffer, but I was originally going to park this with the esp32 and have the lob of memory hooked up there :-) My other plan was actually ordering a custom PCB that has it all in one place (this is the main reason why I didn't bother to solder anything to a perf board). But then I had a little daughter and plans changed, so I shipped the mockup to production. Since it's holding up pretty well I'm quite happy with how it turned out anyway, but I absolutely agree a cleaned-up "v1.0" of this thing would be really nice to do at some point. Also, do note that I'm mainly a software engineer and have no formal training or background in EE, so partly I do these as little hobbyist learning projects and to do something with my hands. If your day consists of Alt-Tabbing between your EDA and your Mouser/Digikey order tracking I'm sure you'd approach this very differently and iterate it much more on the screen first :)
StevenNunez 2y ago
This is so cool! I always dream of doing this but don't know where to start. Even using old LCDs for new and interesting form factors would be a dream. Nice work on this!
- sho_hn 2y ago
  Thanks! The main difficulty & goal with this one was reducing the power consumption to the absolute minimum, which meant putting some effort into component choices and I also ended up writing the display controller driver myself. But if you just want to get going, you don't really need to go through that sort of trouble. You can just buy a panel + controller board via a retailer like e.g. Waveshare, and hook them up to a computer. Quite a few of these controller boards even have HDMI input, or come with SDK code for e.g. Raspberry Pi if they use SPI over GPIO. You can tinker quite a bit without things getting more challenging, and if you can arrange for wired power you may not really need to optimize anything.
fosh 2y ago
This is so polished! Have you shared the latex / other bits anywhere ?

deleted 2y ago

[deleted]

brian-armstrong 2y ago

There's Visionect if you want to go large enough to see on the wall at a glance (32") https://www.visionect.com/shop/place-play-32/ https://www.visionect.com/shop/place-play-32/

xienze 2y ago
Perhaps a requirement left unsaid by OP, but something reasonably priced. $2500 is a bit rich for what it would be used for.
- brian-armstrong 2y ago
  $2500 isn't too far off of the BOM for epaper this large, plus some markup for the assembler. Even if you bought this as a bare panel and a battery on Alibaba, you're not going to do better than $1500 or so. At current date that's just what it costs
grogenaut 2y ago
it's just absurdly priced though when you compare with a 80"+ tv, I get it, its different lower volume tech, but chicken and egg.
- rbanffy 2y ago
  Indeed. This is the issue with these panels. They tend to be prohibitively expensive. Worth for signage because labour costs will dominate in the long run. I suspect this is what dictates the panel prices.

jwithington 2y ago

Trmnl was referenced but also this one https://learn.pimoroni.com/article/getting-started-with-badger-2040 https://learn.pimoroni.com/article/getting-started-with-badg...

bitdivision 2y ago

https://www.waveshare.com/product/13.3inch-e-paper-hat-plus-e.htm https://www.waveshare.com/product/13.3inch-e-paper-hat-plus-... The spectra color displays seem to be available cheaper than I expected ($250). Note that the refresh cycle is really long on these though. I'm now tempted to put something together.