Throughout the last 2 days I have worked on getting all the relevant outputs of the Nicla Board in the Serial Monitor, from the sensors on board, by using the relevant information from the Resource Page: https://docs.arduino.cc/tutorials/nicla-sense-me/cheat-sheet#sensors.
As have been specified in the other posts, the Nicla has 4 main sensors on board, which are: BHI260AP (IMU), BME688,(4-in-1 Gas sensor) BMP390(Barometric Pressure), BMM150(Magnetometer). Webpage here: https://www.bosch-sensortec.com/software-tools/tools/arduino-nicla-sense-me/.
The outputs from the BHY2 Nicla Library are:
Temperature - BMP390
Humidity - BMP390
Pressure - BMP390
Temperature (with chip heating compensation algorithm) - BME688
Humidity (with chip heating compensation algorithm) - BME688
Gas Resistance - BME688
Air Quality Index - BME688
Volatile Organic Compounds - BME688
CO2 Equivalent - BME688
Magnetometer X/Y/Z - BMM150
Gravity Vector X/Y/Z (algorithmically calculated) - BMM150
IMU Tilt Detected (Bosch factory ML trained on tilt event identification) - BHI260AP
IMU Step Detector (Bosch factory ML trained on tilt event identification) - BHI260AP
IMU Step Counter (Bosch factory ML trained on tilt event identification) - BHI260AP
Manually calculated outputs with the Nicla Sensor Data:
Altitude (from temperature and pressure data)
Air density (from temperature, humidity, pressure)
Discomfort Index (from temperature and humidity)
Air Quality Description (from IAQ table, check Appendix)
Measurements needed to improve air and reduce CO2 presence (from CO2_eq ppm)
Compass (Heading from Magnetometer+Gyro+Accelerometer Fusion)
Rainfall Probability (Linear Regresor ML Trained with temperature, humidity, pressure)
Sensor fusion:
Temperature - BMP390 & BME688 (with added MLX90614 ambient temps)
Humidity - BMP390 & BME688
The air density, discomfort index, compass and rainfall probability are still to be implemented in the following days. The current code outputting everything looks like the following:
#include "Arduino.h"
#include "Arduino_BHY2.h"
Sensor humidity(SENSOR_ID_HUM);
Sensor temperature(SENSOR_ID_TEMP);
Sensor pressure(SENSOR_ID_BARO);
Sensor gas(SENSOR_ID_GAS);
SensorBSEC bsec(SENSOR_ID_BSEC);;
SensorXYZ magnetometer(SENSOR_ID_MAG);
SensorXYZ gravity_vector(SENSOR_ID_GRA);
SensorOrientation orientation(SENSOR_ID_ORI);
SensorOrientation device_orientation(SENSOR_ID_DEVICE_ORI);
Sensor tilt(SENSOR_ID_WRIST_TILT_GESTURE);
String compound = "";
String air_quality = "";
float sea_level_pressure = 1013.25;
void setup(){
Serial.begin(115200);
BHY2.begin();
temperature.begin();
humidity.begin();
pressure.begin();
gas.begin();
bsec.begin();
magnetometer.begin();
gravity_vector.begin();
orientation.begin();
tilt.begin();
device_orientation.begin();
}
void loop(){
static auto lastCheck= millis();
BHY2.update();
// Check sensor values every second
if (millis() - lastCheck >= 1000) {
lastCheck = millis();
//the word "Temperature" is already taken by the Nicla board, so I use "temp_value"
float temp_value = temperature.value();
int hum_value = humidity.value();
int gas_resistance = gas.value();
float pressure_value = pressure.value();
int iaq = ((bsec.toString()).substring(25,28)).toInt();
float voc_eq = ((bsec.toString()).substring(53,57)).toFloat();
int co2_eq = ((bsec.toString()).substring(68,72)).toInt();
int accuracy = ((bsec.toString()).substring(84,85)).toInt();
float comp_temp = ((bsec.toString()).substring(95,101)).toFloat();
int comp_hum = ((bsec.toString()).substring(112,117)).toInt();
int comp_gas_res = ((bsec.toString()).substring(128,130)).toInt();
float temp_fusion = (temp_value+comp_temp)/2;
float humidity_fusion = (hum_value+comp_hum)/2;
int altitude = ((pow((sea_level_pressure/pressure_value), (1/5.257)) -1) * (temp_fusion + 273.15))/0.0065; //altitude hypsometric formula
if (voc_eq < 5.0) compound = "Clean Air! No Volatile Compounds Detected!";
else if (5.0 < voc_eq < 10.0) compound = "Ethane Alkane Detected!";
else if (10.0 < voc_eq < 15.0) compound = "Isoprene/Methyl/Butadiene/Ethanol Detected!";
else if (15.0 < voc_eq < 40.0) compound = "Carbon Monoxide Detected!";
else if (voc_eq > 50.0) compound = "Acetone Detected!";
if (iaq < 50) air_quality = "Pure air. No mmeasures needed!";
else if (50 < iaq < 100) air_quality = "Good Air! No irritation or impact on well-being. No health measures needed! ";
else if (100 < iaq < 150) air_quality = "Lightly polluted air! Reduction of well-being possible! Fresh air or ventilation suggested!";
else if (150 < iaq < 200) air_quality = "Moderately polluted. Reduction of well-being possible! Increase ventilation with clean air!";
else if (200 < iaq < 250) air_quality = "Heavily polluted. Continous exposition might lead to migraines! Immediately increase ventilation or leave the environment!";
else if (250 < iaq < 350) air_quality = "Severely polluted. Severe health issues possible! Contamination should be identified! Maximise ventilation or leave environment";
else if (iaq > 350) air_quality = "Extremely polluted. Neurotoxic effects possible! Contamination must be identified! Avoid the environment!";
Serial.println(String("Temperature is: ") + String(temp_value) + String(" C"));
Serial.println(String("Compensated Temperature is: ") + String(comp_temp) + String(" C"));
Serial.println(String("Humidity is: ") + String(hum_value) + String(" %"));
Serial.println(String("Compensated Humidity is: ") + String(comp_hum) + String(" %"));
Serial.println(String("Pressure: ") + String(pressure_value) + String(" hPa"));
Serial.println(String("Altitude: ") + String(altitude) + String(" m"));
Serial.println(String("Gas resistance: ") + String(gas_resistance));
Serial.println(String("Compensated Gas Resistance is: ") + String(comp_gas_res) + String(" Ohms"));
Serial.println(String("Temperature Fusion is: ") + String(temp_fusion) + String(" C"));
Serial.println(String("Humidity Fusion is: ") + String(humidity_fusion) + String(" %"));
Serial.println(String("Air Quality Index is: ") + String(iaq));
Serial.println(String("Volatile Organic Compounds: ") + String(voc_eq) + String(" ppm"));
Serial.println(compound);
Serial.println(String("Estimation of CO2 levels: ") + String(co2_eq) + String(" ppm"));
Serial.println(String("IAQ Accuracy Level: ") + String(accuracy));
Serial.println(air_quality);
Serial.println(String("Magnetometer info: ") + magnetometer.toString());
Serial.println(String("Gravity Vector info: ") + gravity_vector.toString());
Serial.println(String("Tilt info: ") + tilt.toString() + String(" - Binary value:") + tilt.value());
Serial.println(String(orientation.toString()));
}
}Here is how the output looks in the Serial Monitor:
Here is a serial monitor focused image:
The next progress will be on implementing Air Density, Discomfort Index, Compass and a Linear Regression Supervisor ML mode for precipitation prediction.
Appendix:
Bosch IAQ Table: https://community.bosch-sensortec.com/t5/image/serverpage/image-id/10360i868E116504889E8C/image-size/large?v=v2&px=999)
Discomfort Index Formula and Online Calculator: https://keisan.casio.com/exec/system/1351058230
Air Density Forumla and Calculator: https://www.easycalculation.com/physics/thermodynamics/air-density.php
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