Summary
Add support for a second input channel that can be sampled like the existing DHT extra-sensor readings, but as a simple analog value. Stephen described this as high importance for expanding WaterPAL beyond the current pump-use input.
Use cases
Potential sensors / applications mentioned:
- IR sensors for solar pumps
- Grease detection
- Handle movement detection
- Other plug-in analog Arduino-style modules
Example sensor links from the discussion:
Stephen confirmed analog is enough, and thresholding can happen on the database side.
Requested behavior
- Sample one additional analog input on a regular schedule, similar to how DHT temperature / humidity readings are sampled.
- Store and report the analog readings alongside existing extra sensor values where practical.
- Do not apply firmware-side thresholds initially; send raw analog values so database / backend logic can classify them later.
Hardware / pin note
Stephen asked whether a second line on GPIO 0 could be sampled like DHT. The current firmware config comments warn that GPIO 0, 2, 12, and 15 are used for boot mode selection and may not be good wake-up sources, so this issue should confirm the final pin choice before implementation.
Acceptance criteria
- Firmware has a configurable analog input pin for the new sensor channel.
- The analog value is sampled on the same cadence as the existing extra sensor reads, unless a better cadence is intentionally chosen.
- Readings are included in outgoing reporting in a way the backend can store and threshold later.
- Existing DHT humidity / temperature readings continue to work.
- GPIO 0 suitability is verified or an alternate safe ADC-capable pin is selected and documented.
Source
From Stephen Peacock's punchlist:
One powerful feature is to add a second input. high importance. IR sensors for solar pumps, grease detection, handle movement etc.
Could you add a second line on GPIO 0 to sample like DHT does? This will work.
We can just take a single analog input. The threshold can be on the database side.
Priority order from Stephen: (2) second input for analog sensing that can be treated like DHT sensor.
Summary
Add support for a second input channel that can be sampled like the existing DHT extra-sensor readings, but as a simple analog value. Stephen described this as high importance for expanding WaterPAL beyond the current pump-use input.
Use cases
Potential sensors / applications mentioned:
Example sensor links from the discussion:
Stephen confirmed analog is enough, and thresholding can happen on the database side.
Requested behavior
Hardware / pin note
Stephen asked whether a second line on GPIO 0 could be sampled like DHT. The current firmware config comments warn that GPIO 0, 2, 12, and 15 are used for boot mode selection and may not be good wake-up sources, so this issue should confirm the final pin choice before implementation.
Acceptance criteria
Source
From Stephen Peacock's punchlist:
Priority order from Stephen:
(2) second input for analog sensing that can be treated like DHT sensor.