🛠️ door buzzer
Next Canada wanted me to solve a problem for their co-working space: people were leaving a certain door open after-hours - it was fine to be open during office-hours (it was the most convenient route to the bathroom) - but they wanted to make sure people wouldn't leave it open when no one was there.
Solution:
- a Raspberry Pi Zero
- with a Hall sensor (to detect whether the door is open or closed)
- and a piezo buzzer
- powered by an ethernet-to-USB adapter
- scripted to buzz annoyingly if the door was left open for more than 30 seconds outside of office-hours (9-5 M-F)
- (and to email administrators in case it was left open)
An ESP-32 probably would have been sufficient (with the benefit of using less power and lower cost), but I went with Pi Zero because I knew it would definitely work (and there was a risk that the time I spent fiddling outside of my comfort zone would have cost more than the hardware). This choice was further vindicated when I used the same Pi Zero to run the Wifi Guestbook System.
This was actually my first IOT project that involved peripherals like the sensor and the buzzer. After years of making "virtual" software solutions, it was super satisfying to create something "real."
It's been running non-stop for almost 2 years now. Like clock-work, when 5pm hits, the door buzzes and someone nearby closes it.
Frustratingly however... several months after installing it, the organization started putting a door stopper on the main entrance door, and they don't seem to mind it being left open after-hours. SMH.