Results
This page separates what the firmware is known to do from what has not been measured yet.
Implemented behaviour
Every item below is implemented in src/main.cpp and listed in the repository README.
| Behaviour | Where it is documented |
|---|---|
| MQ-2 gas reading, LPG and smoke | MQ-2 sensing |
| DHT22 temperature and humidity | DHT22 climate monitoring |
| PIR motion detection and wakeup | PIR sensing and wakeup |
| 16x2 I2C display with live sensor values | LCD interface |
| Countdown of seconds remaining before sleep | LCD interface |
| Deep sleep after 20 seconds without motion | Low-power architecture |
| LCD backlight off while asleep | Low-power architecture |
| Battery operation | Hardware |
Display output
The two display lines are fixed by the firmware:
Line 1: Gas:XXXX T:XX.X gas value and temperature
Line 2: H:XX.X M:X XX humidity, motion flag, seconds until sleep
What is not measured
The repository does not contain measurement data, so these figures are unknown:
- battery life in days or months. The README describes it as “estimated months on a single charge”, which is an estimate, not a measurement
- MQ-2 response time or sensitivity drift over time
- false wake-up rate from the PIR in a real kitchen
- the current draw in each sleep state
Recording these would need a bench setup with a current meter and a timed run. Until then the numbers are marked unknown rather than estimated.