Another Step Closer: Interface Choices Narrowed

A project log for Raspberry Pi Checklist

Digital, portable, open source, and simple checklist for every day carry. Replace apps and paper for good.

dustinDustin 11/01/2021 at 01:330 Comments

The big announcement is that I purchased some new hardware that will make development far easier for me. I picked up a Pidock 400 and a Raspberry Pi 400 kit for my PiCarts project. I got it to consolidate all of my project work onto one system that's more portable than my laptop, which now has a broken screen. I can use the Pi 400 as a USB keyboard, and the display on the Pidock is standard HDMI, so I can use it with the Pi Zero. This will make it easy to take all my project materials with me in a single laptop bag, so I can work anywhere at any time. Setting up my laptop and digging out all the equipment has been a huge obstacle for me, so I just don't do it. 

I'm amazed that people still keep liking and following this project. I understand why though. There isn't really much else like it out there. I've recently ordered a Pi Zero 2 W, which may end up in this device. It's actually fast enough to be used as a very basic personal computer, unlike the original Pi zero w. I really want this thing to be more than just a checklist. My idea for it is basically a general use pocket computer that can be used as a standalone checklist. I've been working with the Raspberry Pi Pico lately and could use that instead. It's $4, which is nice, and plenty of power. I very well may make both versions in the future. I still need to decide on a screen. I'm leaning towards e-ink displays these days, though they tend to be more expensive. Battery life with a Pico and e-ink display would be fantastic. As the Pico can be used as a USB mass storage device, I might be able to just drop the text file containing the lists onto it and go. No OS, no SD cards, no shutdown procedures. The Pico could easily run the screen, external data storage, an LED for flash light, and much more. I'd love to add temperature, humidity, and atmospheric pressure sensors eventually for keeping an eye on the weather and such. Gotta watch out for feature creep though. 

I just discovered this setup from a Adafruit that is almost exactly what I want. I don't know how it would handle pocket lint and such, but it would be perfect for a prototype. It's out of stock currently, but I can get the pieces individually instead of the kit. I'm already planning to learn pygame, which is recommended for this display. The other option I'm considering is this e-ink display, also from Adafruit. It's a three color display: black, white, red. They also make black, white, and yellow, as well as a plain black and white version. There are no buttons on these displays, but they could be added later. The OLED option above is actually the better of the two, as it will enable me to actually get this project done. Less obstacles to tackle. 

While searching through various Pi stuff, I came across a third option that I really enjoy: The Pirate Audio Speaker and Display for Raspberry Pi. It has a nice little screen, buttons, a speaker, and DAC so it can playback audio. It's just a 1 watt speaker, but it would add sound effects to the device. I really do want something with buttons on it and this is a great option.

I've found another great option here, again from Adafruit. It's actually a LoRa module with a small screen and three buttons. I find this one quite fascinating as it would add long distance wireless communications. A checklist that can be used as a communicator. With only three buttons, that might be hard to use, even as a checklist. I'll still likely pick up a few and tinker with them. I'm putting together a large kit of Pi hardware for testing and to just play around with. This would be a great addition. I could set up the Pi to connect to a smartphone through Bluetooth for text input and such. Basically make a LoRa modem for smartphones. It would be great for communicating in places without cell service, such as underground or the middle of nowhere. Feature creep though...

Alright, I think I've looked at enough displays and such. The current leader is still the OLED with the joystick and two buttons. I'll start by ordering that and a few others. Once I have that display working and understand how to program it, I'll get some checklist code up on GitHub. My top priority project is PiCarts, so I don't know how quickly I'll have a working prototype of the Pi checklist working. I'm closer than ever having decided on the hardware and ordered the development hardware. I really like the idea of being able to plug this into a display and run a full computer. The core feature will be the checklist. Once that is done, other features can be added so long as they don't interfere with the checklist aspect. 

I suppose I should touch on making this device portable and pocket safe. I was thinking about using a rubber gasket of some sort sandwiched between the two boards to keep lint and such out. I can always coat the boards in a waterproof coating, the name of which has just escaped me. Add in a Pi Zero case, and that would be pretty much ready to go. I still need to sort out battery power. I'm sure there's something out there. Just need to do the research. It could possibly be powered off a smartphone, but that's not an ideal situation at all. 

Next paycheck I'll see about setting aside the funds for the display for this project. I may even just get a few, since I have a few Pi zeros hanging around doing nothing. Might make myself a little info board out of one. The new Pi Zero 2 W is on the way, I've got really nice development hardware for multiple projects, and some funding is on the way. Expect some more updates on this project as well as a hardware prototype soon.