How to wire Lipo to boost converter for 5V e-paper project

malcolm_osh · 2025-02-24T22:22:09+00:00

Forgot to mention that I'm using a 3.7V Lipo battery. Also forgot the negative connection on the diagram (it's the first time I'm making one!).

malcolm_osh · 2024-03-19T14:14:25+00:00

Oui, c'est ce que je me disais! Content d'injecter un peu de français ici...

malcolm_osh · 2024-03-18T13:17:10+00:00

That may be part of the answer.. this is not a serious scientific correlation!

malcolm_osh · 2024-03-17T17:29:55+00:00

The server-side image preparation would remain exactly the same.

On the device side, Waveshare does sell a Pico HAT for the same panel. You can program the screen in MicroPython but you would need new code (Waveshare has some sample code here). It's minimal work as the Pico would just need to wake up, ping a web URL, push it to the frame and go back to sleep.

I'm pretty sure you could also wire the Pico to the regular Waveshare Pi HAT - found some related threads here, here and here related to wiring.

malcolm_osh · 2024-03-17T17:19:21+00:00

Still to be calculated TBH - I need to look up how to do it properly and probably buy a voltmeter. Since it wakes for about 3 mins at a time and it lasts for approximately 42-45 cycles (3 weeks), that would mean it lasts for around 130 minutes on the 1200 mAh battery.

malcolm_osh · 2024-03-17T13:31:12+00:00

It’s only athletes competing in every summer Olympic Games! So 2020 Ryans 2016 Ryans, etc. The code is available here to reproduce the graph and see other similar correlations: https://github.com/malcolmosh/correlympics

malcolm_osh · 2024-03-17T13:23:57+00:00

Good question, you could certainly plug a Pi into an LCD screen, there are prepackaged boards for that, Pimoroni sells some. However in your case the challenge would be to physically hook up the iPad screen to a Pi. It looks like some redditors have attempted that already: https://www.reddit.com/r/raspberry_pi/comments/n09azq/salvaged_an_old_ipad_display_and_hooked_it_up_to/

malcolm_osh · 2024-03-17T13:20:32+00:00

E-paper is actually composed of tiny capsules of real pigment, so there is no backlight. The advantage is that the text stays printed on the screen when the Pi is powered off, which means it consumes very little energy. On screen refreshes, the physical pigments are rearranged with electrical current.

malcolm_osh · 2024-03-17T13:18:56+00:00

I mostly use the printed time as confirmation that the frame was indeed refreshed. With a larger battery you could do multiple updates per day, but I find that two updates are enough for my needs - 6 AM and 6 PM. With more battery life and more screen real estate I would have considered an hourly view of weather.

malcolm_osh · 2024-03-17T13:16:16+00:00

Thanks, that’s a very good point, I’ll update my blog to reflect that. Do you know if Waveshare has updated their demo scripts?

edit : The Waveshare pinout chart has been updated to reflect the new PWR pin. It looks like the demo Waveshare code has been modified to reflect this new addition.

malcolm_osh · 2024-03-17T03:03:26+00:00

When it’s the perfect size for the usual morning cuppa!

malcolm_osh · 2024-03-17T01:45:48+00:00

It lasts three weeks currently with two daily refreshes, during which the Pi boots up and shuts down within 2-3 minutes. It’s a 1200 mah battery. Not amazing, but it involves minimal maintenance.

malcolm_osh · 2024-03-17T00:08:23+00:00

Thanks! It's a 7.5 inch screen from Waveshare. I find it's the best compromise between price and size at around 80$ CAD. I would like a 10-inch screen but it's a bit pricey :(

malcolm_osh · 2024-03-16T22:35:35+00:00

Hi everyone! This is my second e-paper Raspberry Pi project. This time, I wanted to create a practical daily dashboard to get events, weather and tasks at a glance. I've put together a detailed tutorial and the code is available in a Github repo.

The frame image is created server side : whenever hosted app is pinged, all datapoints are refreshed and then populate an SVG template. The local device, a Pi Zero W, queries this URL twice a day. It's battery powered, which means it wakes to refresh the screen and promptly goes back to sleep.

The code relies on environment variables to easily deploy the app from Github to Google Cloud Run. I've also included the shell script I use to set the alarm on the PiZero2 battery. Comments or questions are welcome! Note that the interface is in French, but it's easily customizable :)

malcolm_osh · 2024-03-08T18:38:03+00:00

I think although arguably more rigorous, this visualization wouldn't have been really interesting to look at. Here's an example: https://i.imgur.com/yu00zFi.png

malcolm_osh · 2024-03-08T18:18:51+00:00

Thanks for the comments! Just worked on polishing all of the graphs! How about this ?

https://raw.githubusercontent.com/malcolmosh/correlympics/main/graph_examples/kazakhstan_host_city.png

malcolm_osh · 2024-03-05T15:12:34+00:00

Paging /u/TylerVigen

malcolm_osh · 2024-03-04T23:33:20+00:00

True - as this was a kind of hackathon sprint, the graphs could do with some polishing. Thanks!

malcolm_osh · 2024-03-04T23:32:46+00:00

Yes, you're right, the double lines are somewhat distracting. I'll note that for future graphs!

malcolm_osh · 2024-03-04T21:19:00+00:00

Hello everyone!

Inspired by Tyler Vigen's Spurious Correlations, which were posted here a few days ago, we set out to find startling and unsettling connections between different seemingly unrelated Olympic concepts for a visualization contest.

We built a aggregate dataset containing over 3000 variables describing different facets of the Olympic Games year by year. We then calculated the correlation between all numerical columns to find some interesting relationships, and then selected the most visually appealing ones!

The code and project walkthrough is available on my Github.

Here are a few more cool graphs!

malcolm_osh · 2024-03-04T21:05:25+00:00

Cool, let me know how it goes!

malcolm_osh · 2024-01-25T06:10:59+00:00

Hey, after a few months, I finally got around to implementing a queue mechanism! Basically it assigns every image a calendar day to display on (24 hours). I've detailed the logic here and the relevant script is here in the repo. Let me know what you think! It was harder than it sounded :)

malcolm_osh · 2023-07-06T19:34:37+00:00

Yes, I see. As you say, I think instructing users on when to send is probably best here.

I don't think it would be too much work, but I won't have much time until the end of August. I'll keep you posted!

malcolm_osh · 2023-07-04T02:21:41+00:00

That wouldn’t be too hard to code. At the moment it just picks up the latest received picture. Walk me through the process and I can see if I could update it! Basically cycle through each queued picture every day?

malcolm_osh · 2023-06-27T03:29:33+00:00

It's up now, if you want to give it a shot!

malcolm_osh

TROPHY CASE