├── HA_view.png
├── LICENSE
├── README.md
└── bme680-air-quality-RC.py


/HA_view.png:
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https://raw.githubusercontent.com/robmarkcole/bme680-mqtt/HEAD/HA_view.png


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/LICENSE:
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 1 | MIT License
 2 | 
 3 | Copyright (c) 2017 Robin
 4 | 
 5 | Permission is hereby granted, free of charge, to any person obtaining a copy
 6 | of this software and associated documentation files (the "Software"), to deal
 7 | in the Software without restriction, including without limitation the rights
 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 9 | copies of the Software, and to permit persons to whom the Software is
10 | furnished to do so, subject to the following conditions:
11 | 
12 | The above copyright notice and this permission notice shall be included in all
13 | copies or substantial portions of the Software.
14 | 
15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 | SOFTWARE.
22 | 


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/README.md:
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 1 | # bme680-mqtt
 2 | Modifies example by [Pimoroni](https://github.com/pimoroni/bme680/blob/master/examples/indoor-air-quality.py) to publish [bme680](https://learn.pimoroni.com/tutorial/sandyj/getting-started-with-bme680-breakout) data via MQTT.
 3 | 
 4 | To add the MQTT output to [Home-assistant](https://home-assistant.io/), we use an [MQTT-switch](https://home-assistant.io/components/switch.mqtt/). Assuming you have your Home-assistant [config split](https://home-assistant.io/docs/configuration/splitting_configuration/) into seperate files, in your sensors.yaml file, add the following:
 5 | 
 6 | ```yaml
 7 | - platform: mqtt
 8 |   name: 'bme680-temperature'
 9 |   state_topic: 'bme680-temperature'
10 |   unit_of_measurement: '°C'
11 | - platform: mqtt
12 |   name: 'bme680-humidity'
13 |   state_topic: 'bme680-humidity'
14 |   unit_of_measurement: '%'
15 | - platform: mqtt
16 |   name: 'bme680-pressure'
17 |   state_topic: 'bme680-pressure'
18 |   unit_of_measurement: 'hPa'
19 | - platform: mqtt
20 |   name: 'bme680-air_qual'
21 |   state_topic: 'bme680-air_qual'
22 |   unit_of_measurement: '%'
23 | ```
24 | 
25 | I then created a group, in groups.yaml:
26 | 
27 | ```yaml
28 | BME680:
29 |   entities:
30 |     - sensor.bme680temperature
31 |     - sensor.bme680pressure
32 |     - sensor.bme680humidity
33 |     - sensor.bme680air_qual
34 | ```
35 | 
36 | Finally you may want to [customise](https://home-assistant.io/docs/configuration/customizing-devices/) the look of the sensors in the Home-assistant front end. 
37 | 
38 | <img src="https://github.com/robmarkcole/bme680-mqtt/blob/master/HA_view.png">
39 | 


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/bme680-air-quality-RC.py:
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  1 | #!/usr/bin/env python
  2 | 
  3 | import bme680
  4 | import time
  5 | 
  6 | import paho.mqtt.client as mqtt
  7 | import paho.mqtt.publish as publish
  8 | 
  9 | print("""Estimate indoor air quality
 10 | 
 11 | Runs the sensor for a burn-in period, then uses a 
 12 | combination of relative humidity and gas resistance
 13 | to estimate indoor air quality as a percentage.
 14 | 
 15 | Press Ctrl+C to exit
 16 | 
 17 | """)
 18 | 
 19 | ### MQTT
 20 | broker = '192.168.0.30'
 21 | topic ='test'
 22 | 
 23 | client = mqtt.Client()
 24 | client.connect(broker)
 25 | client.loop_start()
 26 | 
 27 | ### bme680
 28 | 
 29 | sensor = bme680.BME680()
 30 | 
 31 | # These oversampling settings can be tweaked to 
 32 | # change the balance between accuracy and noise in
 33 | # the data.
 34 | 
 35 | sensor.set_humidity_oversample(bme680.OS_2X)
 36 | sensor.set_pressure_oversample(bme680.OS_4X)
 37 | sensor.set_temperature_oversample(bme680.OS_8X)
 38 | sensor.set_filter(bme680.FILTER_SIZE_3)
 39 | sensor.set_gas_status(bme680.ENABLE_GAS_MEAS)
 40 | 
 41 | sensor.set_gas_heater_temperature(320)
 42 | sensor.set_gas_heater_duration(150)
 43 | sensor.select_gas_heater_profile(0)
 44 | 
 45 | # start_time and curr_time ensure that the 
 46 | # burn_in_time (in seconds) is kept track of.
 47 | 
 48 | start_time = time.time()
 49 | curr_time = time.time()
 50 | burn_in_time = 1  # burn_in_time (in seconds) is kept track of.
 51 | 
 52 | burn_in_data = []
 53 | 
 54 | try:
 55 |     # Collect gas resistance burn-in values, then use the average
 56 |     # of the last 50 values to set the upper limit for calculating
 57 |     # gas_baseline.
 58 |     print("Collecting gas resistance burn-in data for 5 mins\n")
 59 |     while curr_time - start_time < burn_in_time:
 60 |         curr_time = time.time()
 61 |         if sensor.get_sensor_data() and sensor.data.heat_stable:
 62 |             gas = sensor.data.gas_resistance
 63 |             burn_in_data.append(gas)
 64 |             print("Gas: {0} Ohms".format(gas))
 65 |             time.sleep(1)
 66 | 
 67 |     gas_baseline = sum(burn_in_data[-50:]) / 50.0
 68 | 
 69 |     # Set the humidity baseline to 40%, an optimal indoor humidity.
 70 |     hum_baseline = 40.0
 71 | 
 72 |     # This sets the balance between humidity and gas reading in the 
 73 |     # calculation of air_quality_score (25:75, humidity:gas)
 74 |     hum_weighting = 0.25
 75 | 
 76 |     print("Gas baseline: {0} Ohms, humidity baseline: {1:.2f} %RH\n".format(gas_baseline, hum_baseline))
 77 | 
 78 |     while True:
 79 |         if sensor.get_sensor_data() and sensor.data.heat_stable:
 80 |             gas = sensor.data.gas_resistance
 81 |             gas_offset = gas_baseline - gas
 82 | 
 83 |             hum = sensor.data.humidity
 84 |             hum_offset = hum - hum_baseline
 85 | 
 86 |             # Calculate hum_score as the distance from the hum_baseline.
 87 |             if hum_offset > 0:
 88 |                 hum_score = (100 - hum_baseline - hum_offset) / (100 - hum_baseline) * (hum_weighting * 100)
 89 | 
 90 |             else:
 91 |                 hum_score = (hum_baseline + hum_offset) / hum_baseline * (hum_weighting * 100)
 92 | 
 93 |             # Calculate gas_score as the distance from the gas_baseline.
 94 |             if gas_offset > 0:
 95 |                 gas_score = (gas / gas_baseline) * (100 - (hum_weighting * 100))
 96 | 
 97 |             else:
 98 |                 gas_score = 100 - (hum_weighting * 100)
 99 | 
100 |             # Calculate air_quality_score. 
101 |             air_quality_score = hum_score + gas_score
102 |             
103 |             humidity = str(round(hum, 2))
104 |             temperature = str(round(sensor.data.temperature, 2))
105 |             pressure = str(round(sensor.data.pressure, 2))
106 |             air_qual = str(round(air_quality_score, 2))
107 | 
108 |             print("Gas: {0:.2f} Ohms,humidity: {1:.2f} %RH,air quality: {2:.2f}".format(gas, hum, air_quality_score))
109 |             
110 |             client.publish('bme680-humidity', humidity)
111 |             client.publish('bme680-temperature', temperature)
112 |             client.publish('bme680-pressure', pressure)
113 |             client.publish('bme680-air_qual', air_qual)
114 |             time.sleep(1)
115 | 
116 | except KeyboardInterrupt:
117 |     pass
118 | 


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