Your Next Smart Home Device is a $30 Used Kindle | Hacker News Reader

Your Next Smart Home Device is a $30 Used Kindle

matthealy.com

107 pointsmetadat9 comments

I have a similar setup at home with an M5Paper[1] to display a daily screenshot of my homeassistant dashboard. It's a neat little device based on an ESP32 chip with an e-ink display and some sensors.

I never thought about using a Kindle, even though I have an old jailbroken Paperwhite... It fits so much better for this usage, and would certainly have saved me days of working around hardware limitation.

[1]: https://shop.m5stack.com/products/m5paper-esp32-development-...

I have thought about doing a similar setup for an in-home dashboard with HA and possible some other widgets, but would really like a larger option. Even a Kindle DX would be better, but getting one of those is still several hundred aud. Are there larger consumer-accessible e-ink displays, or is that kinda it?

Ha, I have a few of these. The script looks handy, I might try it out.

> You may be thinking, “Kindles have famously long battery life. Can I run this without having to plug it in?” The short answer is, not really. In previous iterations of this project I tried hard to make it work. The main challenge is that in order to keep the screen refreshing, we can’t let the Kindle go to sleep — you might get weeks of battery life from a Kindle you use for reading, but it’s because most of that time it’s hibernating. Power consumption is very low when it’s awake and the screen isn’t changing, but it’s not nothing. With a lot of effort (refreshing only once a day, and turning off the wi-fi radio when I wasn’t actively using it), I was able to get the battery life up to about a week. Refreshing only once a day is okay for some purposes, but for data that needs to be fresh it’s not really good enough. Also, having to take the Kindle down to recharge it even once a week got to be pretty annoying.

Haha, yeah. The Kindle does have a timer that allows it to wake up from sleep (there are some tricks to prevent it from crashing). At very low refresh rates (once per day) you should be able to get a good bit more battery life, but I haven't yet tried.

I've also put a lot of thought into this, since I'd really like to hang the thing somewhere without any wires sticking out.

Unfortunately even waking the thing from sleep, connecting to a WiFi and checking for new data requires a significant amount of energy. I've been thinking of ways to reduce this with an external device that would run on BLE, Thread or ESP-Now (and check for data much more efficiently, only waking the device when data is actually available), but I haven't been able to wake the device up via UART. The processor allegedly supports it with an extra kernel parameter, but I haven't been able to get it to work (either I couldn't set the parameter or it had no effect, not sure anymore).

After seeing the post yesterday about the e-ink weather display, I thought about how to do it with a kindle, since they’re (a) cheap and available (b) basically self-contained versions of exactly what parts are needed and most importantly (c) subsidize the high price of the display.

I pretty much came to this same design, although was thinking more about disabling the screensaver and (hopefully) finding a way to tap into the sleep/wake power controls so that the display would only refresh once per day or and hopefully consume a lot less power.

Cool to see someone beat me to it! Although I’m not too surprised.

That is a very cool project and makes perfect sense.

Also I've just realized I am still using my Kindle 3 (the one with keyboard) to read books and it would feel strange to repurpose it to just display screenshots.

I would love to do the same but just with my home-assistant page. So basically showing power consumption, temperature readouts etc. Should be doable I guess?

But does this already exist as a product? I've started resenting involving Alexa and would love something this but ootb

Too bad it is a screenshot instead of Fullscreen website, then you could do buttons as well

First time I heard about BackMarket thank you.

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