How much current would the capacitor/resistor attached to it use?
Modern microcontrollers are insanely power efficient. An ESP32 in "light sleep" (which would be sufficient to serve timer routines) is said to consume <1 mA (at 3.3V), down to ~10 uA (microamps!) in "deep sleep".
In other words, 1 year in deep sleep is 315 ampere-seconds or less than 100 mAh.
Obviously it's irrelevant in this use case (where the goal is running a motor every wake-up cycle), but nowadays, as absurd as it looks, being power-constrained isn't necessarily a reason to not slap something on it that happens to also be able to do cryptography, connect to WiFi and make HTTPS requests.
This does the typical "two short buzzes with a break in between". I think that would be hard with a singe NE555, and of course much more annoying/complicated to fine-tune.
This is great for when I'm on the train and don't want to accidentally glance at another person. I can just hold the rectangle in my hand and stare at it!
Discussion: <https://news.ycombinator.com/item?id=7007731>
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