This project is used to read the CO2 measurements, the related and derived measurements and the air quality index, continuously of the Sensirion SCD30 CO2 and RH/T sensor. Optionally, the project can use an OLED 128x32/x64 SSD1306 display.
The project demonstrates the basics of using the MJD ESP-IDF components "mjd_scd30" (sensor) and "mjd_ssd1306" (OLED) for the ESP32.
Please go to the component directories "components/mjd_scd30" and "components/mjd_ssd1306" for more documentation, installation and wiring instructions, data sheets, FAQ, photo's, etc.
esp32_scd30_sensor_settings_using_libThis project is used to verify that the sensor is working properly, to show all the settings** of the sensor and to run the various calibration modes.
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A decent ESP32 development board. I suggest to buy a popular development board with good technical documentation and a significant user base. Examples: Adafruit HUZZAH32, Espressif ESP32-DevKitC, Pycom WiPy, Wemos D32.
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The peripherals that are used in the project.
-
@tip The README of each component contains a section "Shop Products".
- A working installation of the Espressif ESP-IDF V3.2 development framework** (detailed instructions @ http://esp-idf.readthedocs.io/en/latest/get-started/index.html).
mkdir ~/esp
cd ~/esp
git clone -b v3.3 --recursive https://github.com/espressif/esp-idf.git esp-idf-v3.2
- A C Language editor or the Eclipse IDE CDT (instructions also @ http://esp-idf.readthedocs.io/en/latest/get-started/index.html).
The hardware setup consists of
- An ESP32 development board.
- A Sensirion SCD30 CO2 and RH/T sensor.
- Optional: 128x32/128x64 SSD1306 OLED display.
SCD30 SENSOR PIN LAYOUT:
PIN# PIN NAME Description
---- ---------- -----------
1 VDD Power supply (3.3V for the ESP32)
2 GND Ground
3 SCL/TX I2C Serial Clock / ModBus TX
4 SDA/RX I2C Serial Data / ModBus RX
5 RDY Data Ready Pin
6 PWM PWM output (not supported yet by the hardware)
7 SEL Iface select. Default (floating/pulldown) for I2C. Pullup for ModBus.
WIRING DIAGRAM: MCU - SCD30:
SCD30 PIN# PIN NAME MCU PIN
---------- -------- -------
1 VDD VCC 3.3V
2 GND GND
3 SCL/TX GPIO#21
4 SDA/RX GPIO#17
5 RDY N.C.
6 PWM N.C.
7 SEL N.C.
SSD3106 OLED PIN LAYOUT:
PIN# PIN NAME Description
---- ---------- -----------
1 GND Ground
2 VCC Power supply (3.3V for the ESP32)
3 SCL I2C Serial Clock line
4 SDA I2C Serial Data line
WIRING DIAGRAM: MCU - SSD3106 OLED:
SSD3106 PIN# PIN NAME MCU PIN
------------ -------- -------
1 GND Ground
2 VCC Power supply (3.3V for the ESP32)
3 SCL GPIO#23
4 SDA GPIO#22
The project is used to read continuously in fixed intervals the CO2 measurements, the related and derived measurements and the air quality index, and to show it in the UART debug log and optionally on the OLED Display.
The metrics of each measurement:
- The output metrics of the SCD30 sensor:
- CO2 ppm
- Temperature Celsius
- Temperature Fahrenheit
- Relative humidity %
- Some computed metrics:
- EU IDA Air Quality Category
- Dew point Celsius
- Dew point Fahrenheit
The firmware also reports a summary of the averages, minima and maxima.
More info about the EU EN13779 Air Quality Standard for outdoor indoor:
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https://www.airclean.co.uk/technical-bulletins/indoor-air-quality-european-standard/
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Run
make menuconfigand review/modify the section "MY PROJECT CONFIGURATION". Enable the OLED Display if you have wired up such a display device. @tip You can also change the log level in Components->Logging: use level INFO for normal operation, use level DEBUG for more detailed logging and to get insights in what the component is actually doing. -
Run
make flash monitorto build and upload the example to your board and connect to its serial terminal.
Note: the 1st and 2nd measurement readings are always ignored because those readings are often incorrect.
...
I (425) mjd: ESP free HEAP space: 293732 bytes | FreeRTOS free STACK space (current task): 2044 bytes
I (455) myapp: @doc Wait 2 seconds after power-on (start logic analyzer, let peripherals become active, ...)
I (2465) myapp: OK Task has been created, and is running right now
I (3015) myapp: do mjd_scd30_init()
I (4165) mjd_scd30: SCD30 Log Device Params (*Read again from registers*):
I (4195) mjd_scd30: measurement_interval: 5 (seconds)
I (4225) mjd_scd30: data_ready_status: 0 (boolean)
I (4255) mjd_scd30: automatic_self_calibration: 0 (boolean)
I (4295) mjd_scd30: forced_recalibration_value: 400 (CO2 ppm)
I (4325) mjd_scd30: temperature_offset: 100 (x 0.01°C)
I (4355) mjd_scd30: altitude: 10 (meters)
I (4385) mjd_scd30: firmware_version: 3.66
I (4385) myapp: mjd_scd30_cmd_trigger_continuous_measurement()...
I (4415) myapp: LOOP: NBR_OF_MEASUREMENT_RUNS 10
I (4415) myapp: ***SCD30 MEAS#1 of 10***...
I (11635) myapp: ...data_ready_status: 1
I (11635) myapp: mjd_scd30_cmd_read_measurement...
E (11665) mjd_scd30: mjd_scd30_cmd_read_measurement(). ABORT Ignore the 1st and 2nd measurement reading. The values are somet
imes wrong || err 264 (ESP_ERR_INVALID_RESPONSE)
E (12165) myapp: peripheral_task(). Cannot read measurement | err 264 (ESP_ERR_INVALID_RESPONSE)
I (12165) myapp: ***SCD30 MEAS#2 of 10***...
I (17315) myapp: ...data_ready_status: 1
I (17315) myapp: mjd_scd30_cmd_read_measurement...
E (17345) mjd_scd30: mjd_scd30_cmd_read_measurement(). ABORT Ignore the 1st and 2nd measurement reading. The values are somet
imes wrong || err 264 (ESP_ERR_INVALID_RESPONSE)
E (17845) myapp: peripheral_task(). Cannot read measurement | err 264 (ESP_ERR_INVALID_RESPONSE)
I (17845) myapp: ***SCD30 MEAS#3 of 10***...
I (22995) myapp: ...data_ready_status: 1
I (22995) myapp: mjd_scd30_cmd_read_measurement...
I (23025) myapp: CO2: 792.8 | Temp C: 23.0 | Temp F: 73.4 | RelHum: 37.1 | DewPnt C: 7.5 | DewPnt F: 51.8
I (23025) myapp: EU IDA Air Quality Category: 4 - IDA 4 (Low indoor air quality)
I (23195) myapp: ***SCD30 MEAS#4 of 10***...
I (28355) myapp: ...data_ready_status: 1
I (22995) myapp: mjd_scd30_cmd_read_measurement...
I (28385) myapp: CO2: 838.9 | Temp C: 23.0 | Temp F: 73.4 | RelHum: 37.1 | DewPnt C: 7.5 | DewPnt F: 51.8
...
I (55305) myapp: ***SCD30 MEAS#10 of 10***...
I (60455) myapp: ...data_ready_status: 1
I (60455) myapp: mjd_scd30_cmd_read_measurement...
I (60485) myapp: CO2: 859.9 | Temp C: 23.0 | Temp F: 73.4 | RelHum: 37.5 | DewPnt C: 7.7 | DewPnt F: 52.0
I (60485) myapp: EU IDA Air Quality Category: 4 - IDA 4 (Low indoor air quality)
I (60655) myapp:
I (60655) myapp: REPORT:
I (60655) myapp: NBR_OF_MEASUREMENT_RUNS: 10
I (60655) myapp: nbr_of_valid_runs: 8
I (60665) myapp: nbr_of_errors: 2
I (60665) myapp: METRIC avg min max
I (60675) myapp: ------ ---------- ---------- ----------
I (60685) myapp: CO2 ppm 841.556 792.847 859.907
I (60685) myapp: Temperature Celsius 22.986 22.966 23.018
I (60695) myapp: Temperature Fahrenheit 73.374 73.339 73.432
I (60705) myapp: Relative Humidity 37.276 37.061 37.505
I (60715) myapp: Dew Point Celsius 7.616 7.537 7.719
I (60715) myapp: Dew Point Fahrenheit 51.867 51.760 52.016
I (60725) myapp: mjd_scd30_cmd_stop_continuous_measurement()...
I (60765) myapp: mjd_scd30_deinit()...
I (60765) mjd: *** 19700101000100 Thu Jan 1 00:01:00 1970
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The objective of this well documented Starter Kit is to accelerate the development of your IoT projects for ESP32 hardware using the ESP-IDF framework from Espressif and get inspired what kind of apps you can build for ESP32 using various hardware modules.