Show HN: ePaper.js – Easily create an ePaper display using JavaScript and HTML

Re:Show HN: ePaper.js – Easily create an ePaper display usin... by sdfhbdf on Saturday August 22, 2020 @04:55AM (#24242776)

Looks very cool and promising.

I'm wondering what's the power draw for the Pi with this one since it "Loads index.html in a headless instance of Chromium, using Puppeteer". Isn't Puppeteer quite a power hungry process?

Would it run on Pi Zero with a battery attached and how long would it last with updates once a minute or once every 5 minutes?

I'm thinking about possible projects that would not have AC power all the time, maybe something solar powered for a dashboard outside.

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Re:Show HN: ePaper.js – Easily create an ePaper display usin... by lukehaas on Saturday August 22, 2020 @06:42AM (#24243206)

I built something that's similar to what you're describing, here's an article about it: https://www.hackster.io/lukehaas/e-ink-display-for-daily-new...

It combines a Pi Zero with a 2000mAh lipo, updates every 6 hours and lasts for around 90 days per charge.

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Re:Show HN: ePaper.js – Easily create an ePaper display usin... by taf2 on Saturday August 22, 2020 @08:03AM (#24243554)

Thanks I like the idea of a git pull on boot up.

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Re:Show HN: ePaper.js – Easily create an ePaper display usin... by gregod on Monday August 24, 2020 @11:28AM (#24261585)

I have used an low-power ESP8266 together with a native drawing library for this use case. As getting the drawing perfect is quite cumbersome i have mocked the graphics library in javascript using the canvas api [1].

The syntax is so similar that you can mostly copy and paste the drawing code between js and the arduino project with only a few adjustments. This has the huge advantage that you can use modern JS dev tools including livereload to get the drawing right while still ending up with native code.

[1] https://www.godberit.de/2019/11/08/Mock-for-ESP8266-graphics...

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Re:Show HN: ePaper.js – Easily create an ePaper display usin... by robocollab on Saturday August 22, 2020 @11:00AM (#24244570)

It would be pretty easy to modify the chain of command to have the backend start and stop the Chromium process. I haven't taken any detailed measurements, yet, but I'm guessing simple web pages like the example weather dashboard aren't too CPU intensive to render.

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Re:Show HN: ePaper.js – Easily create an ePaper display usin... by capableweb on Saturday August 22, 2020 @09:33AM (#24244003)

Quick idea: even though Chromium (not Puppeteer) is quite power hungry, you only need to run it once every update period and then take a archive/dump of the output that gets fed to the screen, then use this cache copy while shutting down Chromium.

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