DIY : The 555 Executive Decision Maker – Hackster’s Blog
If you need to make an important life decision, you likely reason it out and try to come up with the optimum path for yourself. On the other hand, if a decision isn’t that important or there are two seemingly equal options — like where to go for dinner or what movie to watch — a flip of a coin will suffice. Hacker “lonesolesurfer” wasn’t content with using monetary disks to make his choices, and instead came up with this electronic version.
This device uses a 555 timer along with resistors and a capacitor to determine answers, displayed on a green (yes) or red (no) LED. A mercury switch activates the circuit, so once the double-CR2032 battery pack is turned on, you tilt the device in order to get an answer to your query. It’s a great example of what can be done with only discreet components, and a neat experiment if you want to get started with 555 timers.
It is noted in the explanation video below that lonesolesurfer also made a version with an outer shell constructed out of a dental floss box. They’re a nice size for small projects, and he mentions that they conveniently come apart easily.