Some projects solve real problems. This one solves the most real problem: people walking into my room while I’m mid-build.
The plan
A PIR motion sensor watches the doorway. Uninvited guest → a two-tone alarm plus a blinking red LED. There’s a secret disarm button (location classified).
Where it’s at
- ✅ Motion detection working on the breadboard
- ✅ Alarm tone composed (it’s annoying. perfect.)
- 🔧 Designing the wall mount so it looks official
- 🔧 Stretch goal: log intrusions with timestamps
Zero soldering required for this one — it’s all breadboard. Great first electronics build.