Electronic badge tiny projects

August 15, 2023 6:57 AM

Want to have people solder their own badge as a learning project (soldering). It should ideally be like 5cm around as it will be sewn to clothing. I want a low unit price so sensors and microcontrollers are out, but a pcb print run is feasible. What to do?

Since this is for kinda clubware I would like it to do something, ideally a breath alcohol or a 3 LED noise level device or something. If it could do something when in proximity to other badges that could be fun, like display member concentration or navigate to nearest user. What other things could be fun and/of feasible in mini variants?

posted by Iteki to Technology (5 answers total)

You need to define your budget and parameters more thoroughly than you have in your question. What unit cost are you after?

You’ve said you don’t want “sensors or microcontrollers,” but you want to sense (hey look, sensors) sound or alcohol in the air, and you aren’t going to be able to achieve “display member concentration or navigate to nearest user” without a microcontroller (and a radio, or some kind of optical commas solution). Really, though, microcontrollers can be cheap in quantity (couple of bucks each), as can many types of sensors, though the expertise to design a board and write the firmware is not cheap, if you don’t have it yourself.

The good news is, there are lots of hardware hacker types that do stuff like this. “Badgelife” is the search term you want for the folks who design/build/share this sort of thing. Linked to a 2018 Vice article because it was the top search hit and I’m getting ready to head to work. A lot of those badges are open-source so you can probably hunt down something like what you want, find the design files / firmware source, and get some idea what the BoM Cost (bill of materials — all the stuff that gets soldered to the board, plus the board itself) for them are going to be.
posted by Alterscape at 7:19 AM on August 15, 2023 [2 favorites]

Response by poster: Thanks for the clarification request. I should have specified that I meant arduino etc is off the table, atTiny chips etc are good. I probably want to have as far under 3$ as I can get, with price relative to awesomeness. Other thoughts are POV display, dice, continuity tester, tiny flashlight, lights that synch to music. I’m aware of badge culture, badge is the term I used here, but I’m looking for mefi’s take.
posted by Iteki at 7:27 AM on August 15, 2023

I'd rethink your budget. Even the tiniest sub-dollar micro will need a few bucks in power supply, regulation, and printed-circuit board.

Perhaps look at projects that use a 555 timer (~$0.25) and a few resistors/capacitors like a clap switch.
posted by JoeZydeco at 8:54 AM on August 15, 2023 [3 favorites]

For sub US$5 learn to solder projects better consider cheap simple existing parts kits that can do some of the stuff you mention such as dice or Kitt lights; anything more advanced will raise the unit cost quite a bit, especially when you'd be doing your own PCBs and involve ATTtinies. PCBs aren't really that cheap per board for small runs, and even if the parts used are cheap on their own creating circuits with them still adds up.

If you go for the more nifty stuff you'd also be looking at time and effort in designing the board and software.
posted by Stoneshop at 10:45 AM on August 15, 2023 [2 favorites]

Something like the Vancouver Hack Space Learn to Solder badge? With careful sourcing you could probably get that under $3. I think the design is open source, so you might be able to repurpose it.

(VHS has a designated hater, you should probably know. If you contact the hackspace via social media, you'll probably get someone sliding into your mentions with a link to an article about how terrible the management of VHS is. They are a disgruntled former member who really knows how to maintain a grudge.)
posted by scruss at 2:23 PM on August 15, 2023