Coolant flow rate logger for FCEV & BEV thermal validation. Uses low-cost Digiten sensors with ESP32 to transmit data via BLE to a Python client for real-time visualization and logging. Ideal for testing and optimizing EV thermal management systems.
Model: G1" Male Thread Water Flow Hall Sensor Switch Flowmeter Counter 2-50L/min
- Working range: 2-50L/min
- Max water pressure: 1.75Mpa
- Formula: F=7.5Q-4(L/min)
- Working voltage range: DC5-15V
- Accuracy: ±3%
- Temperature resistance: 80℃
- Female thread external diameter: 32.6mm (1.28")
- Tube length: 60mm (2.36")
- Cable length: 30cm (11.81")
- Dimensions (L×W×H): 60mm × 30mm × 28mm
The ESP32 module is housed in a custom 3D printed enclosure for protection and mounting.
Download: ESP32-WROOM-38 Pin Enclosure on MakerWorld
| Digiten Wire Color | ESP32 Pin | Function |
|---|---|---|
| Red | Pin 19 | 3.3V |
| Black | Pin 38 | GND |
| Yellow | Pin 26 | GPIO 4 |
For remote operation, each flow sensor is powered using a USB-C power bank. The setup uses an onn 10,000 mAh Portable Power Bank with Built-In USB-C Cable (Model: WIABLK 36009564), mounted with double-sided tape.
- Run the flow logger Python script
- Power on your flow meter modules
- Click "Scan for BLE devices"
Note: A filter is applied to display only BLE devices containing the name "FLOW_LOGGER_". This helps mitigate scrolling through numerous BLE devices depending on your location.
Once you add a device, a new window will pop up displaying:
- Live graph of flow rate
- Instantaneous flow rate
- Total coolant flow
- Minimum & maximum flow rates
- Average flow rate
You also have the option to reset these metrics.
You can reliably run up to 5 flow loggers simultaneously before potentially encountering performance issues.
The application includes data logging capabilities. To configure the log file location:
Line 91 in code:
self.log_dir = r"C:\path\to\your\logs"