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#!/usr/bin/env python3 | |
import bme680 | |
from time import time, sleep | |
from prometheus_client import CollectorRegistry, Gauge, push_to_gateway | |
# Setup: | |
# python3 -m pip install bme680 prometheus-client | |
# sudo apt install --no-install-recommends prometheus prometheus-pushgateway | |
BURN_IN_TIME = 1800 # 30 min | |
def get_sensor(): | |
try: | |
return bme680.BME680(bme680.I2C_ADDR_PRIMARY) | |
except IOError: | |
return bme680.BME680(bme680.I2C_ADDR_SECONDARY) | |
def main(): | |
sensor = get_sensor() | |
start_time = time() | |
burn_in_data = [] | |
sensor.set_gas_heater_temperature(320) # "Target temperature in degrees celsius, between 200 and 400" | |
sensor.set_gas_heater_duration(150) # "Heating durations between 1 ms and 4032 ms" | |
sensor.select_gas_heater_profile(0) | |
# Collect gas resistance burn-in values, then use the average | |
# of the last 50 values to set the upper limit for calculating | |
# gas_baseline. | |
print(f'Collecting gas resistance burn-in data for {1800//60} mins\n') | |
while (time() - start_time) < BURN_IN_TIME and len(burn_in_data) < 100: | |
if sensor.get_sensor_data() and sensor.data.heat_stable: | |
gas = sensor.data.gas_resistance | |
burn_in_data.append(gas) | |
print(f'Gas: {gas} Ohms (data: {sensor.data})') | |
sleep(5) | |
gas_baseline = sum(burn_in_data[-50:]) / 50.0 | |
# Set the humidity baseline to 40%, an optimal indoor humidity. | |
hum_baseline = 40.0 | |
# This sets the balance between humidity and gas reading in the | |
# calculation of air_quality_score (25:75, humidity:gas) | |
hum_weighting = 0.25 | |
print('Gas baseline: {0} Ohms, humidity baseline: {1:.2f} %RH\n'.format(gas_baseline, hum_baseline)) | |
registry = CollectorRegistry() | |
g_gas_baseline_ohms = Gauge('sensor_baseline_gas_ohms', 'Gas baseline for this session (ohms)', registry=registry) | |
g_gas_baseline_ohms.set(gas_baseline) | |
g_humidity_baseline_ohms = Gauge('sensor_baseline_humidity_ohms', 'Humidity baseline for this session (ohms)', registry=registry) | |
g_humidity_baseline_ohms.set(hum_baseline) | |
g_gas_ohms = Gauge('sensor_gas_ohms', 'Gas (Ohms)', registry=registry) | |
g_humidity_ohms = Gauge('sensor_humidity_ohms', 'Humidity (Ohms)', registry=registry) | |
g_temperature_degC = Gauge('sensor_temperature_degC', 'Temperature (*C)', registry=registry) | |
g_pressure_hPa = Gauge('sensor_pressure_hPa', 'Pressure (hPa)', registry=registry) | |
g_heat_stable = Gauge('sensor_heat_stable', 'Heat stable', registry=registry) | |
g_air_quality_score = Gauge('sensor_airquality_score', 'Air quality score', registry=registry) | |
while True: | |
sleep(45) | |
g_heat_stable.set(sensor.data.heat_stable) | |
if sensor.get_sensor_data() and sensor.data.heat_stable: | |
gas = sensor.data.gas_resistance | |
gas_offset = gas_baseline - gas | |
hum = sensor.data.humidity | |
hum_offset = hum - hum_baseline | |
# Calculate hum_score as the distance from the hum_baseline. | |
if hum_offset > 0: | |
hum_score = (100 - hum_baseline - hum_offset) | |
hum_score /= (100 - hum_baseline) | |
hum_score *= (hum_weighting * 100) | |
else: | |
hum_score = (hum_baseline + hum_offset) | |
hum_score /= hum_baseline | |
hum_score *= (hum_weighting * 100) | |
# Calculate gas_score as the distance from the gas_baseline. | |
if gas_offset > 0: | |
gas_score = (gas / gas_baseline) | |
gas_score *= (100 - (hum_weighting * 100)) | |
else: | |
gas_score = 100 - (hum_weighting * 100) | |
# Calculate air_quality_score. | |
air_quality_score = hum_score + gas_score | |
g_temperature_degC.set(sensor.data.temperature) | |
g_pressure_hPa.set(sensor.data.pressure) | |
g_gas_ohms.set(gas) | |
g_humidity_ohms.set(hum) | |
g_air_quality_score.set(air_quality_score) | |
push_to_gateway('localhost:9091', job='sensor', registry=registry) | |
print('Gas: {0:.2f} Ohms,humidity: {1:.2f} %RH,air quality: {2:.2f}'.format(gas, hum, air_quality_score)) | |
if __name__ == "__main__": | |
main() |
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