Ask HN: I am looking for resources on RPi Pico / eInk displays

4 pointsbobblywobbles1y ago2 comments

I'm comfortable in programming, but have very little experience in the hardware-side of things; I'm looking to create an eink display that updates once a day with text. I have the capacity to learn what I need to understand in order to finish this hobby-project, but wanted to ask here in order to save time/headaches of those who have accomplished projects like this in the past (eInk newspaper/trading cards/etc.). I bought a RPi Zero 2 W, but I think I need to do this project on a microcontroller in order to reach the battery life goals I desire.

(I am also considering offering payment for guidance if that is allowed on HN- I did not see that it was disallowed!)

My main questions are:

- Raspberry Pi Pico or Arduino Nano? I feel both can accomplish my goals

- I see eInk displays for sale on Alibaba. What is the prerequisite knowledge needed in order to connect one of the displays to a microcontroller? Do these eInk displays come with drivers? How do I physically connect the display to a microcontroller?

- I desire that this device be battery powered that can also be recharged. I see different options in the market, but I'm struggling with understanding power requirements or what is physically possible to connect to a microcontroller (ie. aren't some batteries too strong and would fry the microcontroller?)

- I don't require any internet connectivity, but I know these components need to be physically connected. I've watched some introductory videos on soldering, but are there gotchas?

2 comments

talldayo1y ago

> What is the prerequisite knowledge needed in order to connect one of the displays to a microcontroller?

Basic electronics knowledge. If you're unsure, you can buy a breadboard on the cheap and brush up on the basics before you commit something in stone. You can also buy GPIO header pins that let you create prototypes without soldering the Raspberry Pi directly to the board (a whopping $5 in savings per-prototype!): https://www.amazon.com/MCIGICM-Header-2-45mm-Arduino-Connect...

> How do I physically connect the display to a microcontroller?

Use a prototyping PCB board to connect the I2P and power ledes to a larger board. Most LCDs I've seen only have a few wires for controlling them, on a low refresh-rate display like E-ink I'd imagine it's even simpler.

> I've watched some introductory videos on soldering, but are there gotchas?

Not really! You can go grab a Pinecil for $40~ish bucks and get started whenever you want: https://pine64.com/product/pinecil-smart-mini-portable-solde...

Obvious disclaimers, though: soldering irons get hot, you can irreparably burn yourself if you're not careful. Get a sturdy stand or placemat for the iron, a ball of copper for de-tinning the tip and be extremely careful when you know the iron is hot.

Also; lead solder versus unleaded. Unleaded solder is the current industry standard, since it is almost entirely nontoxic in all forms. However, unleaded solder is better-suited for automated soldering by robots; if you have shaky hands it will be tough to work with. I won't strictly recommend leaded solder for 99% of use-cases, but it's worth knowing (and fearing) the fact that it's there if you ever need an easier option.

al2o3cr1y ago

Most eInk displays use a flexible PCB connector that's going to be quite challenging for somebody who's still learning which end of the soldering iron gets hot.

A breakout board like this one will likely be helpful; it includes the needed connector, some power-supply bits, and an SRAM (since a 300x400 bitmap would eat a substantial fraction of the RAM on a small microcontroller):

https://www.adafruit.com/product/4446

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