Imagine, if you will, a pager. The old devices that go bleep blop and would give you a short message from someone, and that was it. Sometimes you could give an acknowledgement, and some of the fancier ones would even let you respond, but mostly it was a way for someone to remotely poke you on the shoulder.
Nowadays, with our newfangled "cellular telephones" and "3G", communication is instant and two-way, five-way,
maybe even twenty-way??? The possibilities are endless, and I will have no part in it!
But acquiring one of these elusive "pagers" is not as easy as one might believe. The remaining few carriers such as Spok primarily cater to the health care industry, where reliably receiving critical information is treated as more important than a confetti effect when someone writes "birthday". Even with resellers available, POCSAG is notoriously insecure, and from what I've heard, has far spottier coverage than modern cellular bands.
Enter: LoRa. It's not
always better in terms of coverage, but it's at least a much more open standard with encryption built-in. Modules are readily available, and there are multiple development kits that come with an RP2040 already wired up.
This is very early days, and I have nothing to show for it yet. I'm not even particularly versed in electrical engineering! But I figure if I'm going to learn, I should start with something actually interesting to me.
So far, the sub-tasks:
- How advanced should it be? A full keyboard would be too difficult, but acknowledgements or even simple responses (suggested by @iliana) would be nice.
- I'd rather avoid a piezoelectric speaker, as they can be pretty harsh. While this is probably ideal for a pager, I'd rather not annoy everyone around me in the process. I'm thinking of a monophonic synth a la Nokia phones, but that'll involve learning how those actually... work.
- I've been playing with a 16x2 LCD Character display, and it has definitely revealed to me that at least 3 rows are necessary. I'm guessing the driving of the display be the easiest part of the process.
iirc LoRa has much Lo-er Ra when its line-of-sight isn't obstructed, but wiki says even in urban areas the range is about 3 miles, which certainly beats wifi..
would a T9-esque keyboard system be a decent compromise?