Defence water-gun tower to secure sensitive places e.q. kitchen table against curious and hungry animals e.q. cats
DEMO: https://www.youtube.com/watch?v=OmJHNpN56g4
- arduino uno/nano
- 2 HC-SR501 PIR sensors
- resistros approx 330Ω
- LCD I2C with backlight
- power bank
- some box (in my case I used the one from a bicycle stem)
- "lazy garden" water spray (easy to find online)
If you check some "hello world" examples of how to work with PIR sensor and LCD I2C, source code will be self explanatory.