FlowSensor can read out Chinese flow sensor found all over Alibaba and Amazon like these:
These sensors have a turbine wheel with a magnet, and a Hall sensor attached. As designed, a simple counter suffices to read the flow.
Unfortunately these sensors have serious drawbacks: vibrations - for instance caused by a running pump - can cause bouncing on the sensor signal, even if there is no flow at all (eg vent shut).
To fix this, I came up with an experimental contraption: the same mechanics, but two Hall sensors arranged in 90°. This creates a quadrature encoder which is immune to ringing on any single sensor line:
This is a scope shot of the analog signal:
This code can deal with unmodified counter-style sensors as well as quadrature encoders. Select the appropriate target in platformio, build and upload.
while this should easily run on any ESP32 platform, right now only the M5Stack CoreS3 is supported.
git clone --recursive https://github.com/mhaberler/flowsensor.git
Choose target, build and upload.
I used pins 17 and 18 on the Port C (blue) connector of the CoreS3. See https://docs.m5stack.com/en/core/CoreS3 for alternatives
This was built with Squareline Studo, the project lives under squareline-ui.
If you make changes, export the UI files to src/ui
FlowSensor reports the values with BLE Advertising broadcast, like many other sensors, see https://decoder.theengs.io/devices/devices.html for devices working similarily.
Manufacturer ID: made up as 0x4711 - see https://www.4711.com/ for the rationale ;)
Data format:
#ifndef MANUFACTURER_ID
#define MANUFACTURER_ID 0x4711 // https://www.4711.com/en/
#endif
#define FLAG_QUADRATURE 1
typedef struct __attribute__((packed)) {
uint8_t mfidLow;
uint8_t mfidHigh;
uint8_t address[6]; // iOS workaround stupid UUID scheme
int32_t count;
uint32_t last_change;
int16_t rate;
uint8_t batteryLevel;
uint8_t flags;
} mfdReport_t;
