Sensirion SEN5x Micropython Driver

Provides access from ESP32-C3 to all Sensirion SEN5x capability via I2C.

Built With

Tested with the following; "should" work with similar setups.

Sample Usage

from machine import I2C, Pin
from sen5x.sen5x import SEN5x

"""
    Wiring:
        ESP32 Pin 7 ------- SEN5x SCL (internal or external pull-up to 3V3)
        ESP32 Pin 6 ------- SEN5x SDA (internal or external pull-up to 3V3)
        ESP32 5V    ------- SEN5x 5V
        ESP32 GND   ------- SEN5x GND
        ESP32 GND   ------- SEN5x SEL       
"""
ID = 0
SCL_PIN_NUM = 7
SDA_PIN_NUM = 6
FREQ = 50000  # see https://github.com/micropython/micropython/issues/7772

i2c = I2C(ID,
          scl=Pin(SCL_PIN_NUM, pull=Pin.PULL_UP),  # internal pull-up
          sda=Pin(SDA_PIN_NUM, pull=Pin.PULL_UP),  # internal pull-up
          freq=FREQ)

with SEN5x(i2c) as sen:
    print('Product Name:', sen.product_name)
    print('Serial Number:', sen.serial_number)
    print('Data Ready:', sen.data_ready)
    ppm1_0, ppm2_5, ppm4_0, ppm10_0, rh, t, voc, nox = sen.measured_values
    print('PPM 1.0:', ppm1_0, 'PPM 2.5:', ppm2_5, 'PPM 4.0:', ppm4_0, 'PPM 10.0:', ppm10_0)
    print('Humidity:', rh, 'Temp:', t, 'VOC:', voc, 'NOx:', nox)

Code Samples

Getting Started

Setup ESP32
Wire ESP32-C3-DevKitM-1 to Sensirion SEN5x following Wiring comment in examples/main.py
Configure SCL_PIN_NUM, SDA_PIN_NUM in examples/main.py
Copy files to ESP32 root directory
- examples/main.py -> /pyboard/main.py
- sen5x/sen5x.py -> /pyboard/lib/sen5x/sen5x.py
- tools/tools.py -> /pyboard/lib/tools/tools.py
Start REPL
Boot ESP32

I found rshell to be useful.

Documentation

Refer to Sensirion SEN5x Datasheet for property, method & argument details.

SEN5x properties

Property	Has Setter?	Type(s)
product_name	no	str
serial_number	no	str
firmware_version	no	int
data_ready	no	bool
measured_values	no	tuple - ppm 1.0: int - ppm 2.5: int - ppm 4.0: int - ppm 10.0: int - temperature °C: float - humidity: int - voc index: int - nox index: int
measured_values_imperial	no	tuple - ppm 1.0: int - ppm 2.5: int - ppm 4.0: int - ppm 10.0: int - temperature°F: int - humidity: int - voc index: int - nox index: int
measured_values_raw	no	tuple - ppm 1.0: float - ppm 2.5: float - ppm 4.0: float - ppm 10.0: float - temperature: float - humidity: float - voc index: float - nox index: float
temperature_compensation_params	yes	tuple - offset: float - slope: float - time const: int
warm_start_param	yes	int
voc_algorithm_tuning_params	yes	tuple - index offset: int - time offset: int - time gain: int - max duration: int - std initial: int - gain factor: int
nox_algorithm_tuning_params	yes	tuple - index offset: int - time offset: int - time gain: int - max duration: int - std initial: int - gain factor: int
rht_acceleration_mode	yes	int
voc_algorithm_state	yes	bytes(8)
auto_cleaning_interval	yes	int
status	no	int
fan_cleaning_active	no	bool

SEN5x methods

Method	Args	Return
start()	None	None
stop()	None	None
start_measurement()	num checks: int = 100	ready: bool
start_measurement_rht_gas_only_mode()	num checks: int = 100	ready: bool
stop_measurement()	None	None
backup_voc_algorithm_state()	None	None
restore_voc_algorithm_state()	None	None
purge_backup_voc_algorithm_state()	None	None
start_fan_cleaning()	None	None
check_i2c()	None	None Raises SEN5x.NotFoundError
check_for_errors()	None	None Raises SEN5x.StatusError
clear_status()	None	None
reset()	None	None

License

This project is released under the MIT License.

sugarpines/sensirion-sen5x