Filament running out alarm

thingiverse

Edit 2023 June 8: I made an improved version, and also a version that has a speaker grille if you want a louder (if harsher) sound. The new thread side (Version 4) works better with bent/abused thread. The original upload worked fine if your filament was coming off a nice reel for the first time, not so much otherwise. This new version handles that much better. You do NOT need to reprint your existing speaker side if you don't want to, it'll snap together same as Version 3. The new speaker side (Version 4) has a grille. You can use it if you want a louder noise. As above, it'll work with the old version too, so if you only want to make your speaker louder, you can just print this side and replace the equivalent part on your existing thread alarm. ORIGINAL POST: I wanted a little filament alarm, something that would make noise when I was running low on filament in case I was in another room. I don't like retraction+refeeding filament, I prefer to just feed in new as it's going, so I made this. Filament runs through a 2.5mm tunnel, when it runs out it triggers the internal circuit to play an MP3 of your choice. The board I'm using is rechargeable and has a USB micro (sorry) interface so you can plug it into a PC to change out the audio. That's also how it charges. I've also left a slot for the on-off switch, which you might want to use if you use a particularly long mp3 as I did. This is entirely a case for existing electronic parts. Here's the audio board I'm using, it makes this project really trivial: https://www.amazon.com/dp/B09YQYFGHB (not an affiliate link, I am not affiliated and make no money on purchases or referrals.) The switch I had was a common 11x20mm lever switch wired up for normally-off operation. You can use whatever'll fit. I was going to reprint it in a new colour but while I might still do that, this is good enough for the moment. I might update this with better photos if I do. The key thing is: it works. ^_^