Breadboard prototype: validate ATtiny1614 + capacitive sensor

[Commons-Lab-1]

Goal

Build the MVP circuit on breadboard and validate:

• Sensor reads correctly (dry in air, wet in water)
• LEDs cycle through all 3 states
• Self-test mode works (PB3 jumper)
• DIP switch selects presets correctly
• Battery life estimate under real conditions

Steps

1. Wire per hardware/README.md MVP diagram
2. Flash firmware/treeguard-mini/ via UPDI
3. Test sensor in dry soil vs wet soil
4. Trigger watering detection (pour water, verify green LED)
5. Verify lockout (should NOT go red again for 18h)
6. Run self-test (jumper PB3 to GND on boot)
7. Measure current draw in each state

Acceptance

• All 3 LED states observed
• Sensor readings match expected range
• Self-test runs correctly
• Current draw measured and documented