Jens Schmidt / MicrobitIAQ

uses BBC micro:bit to measure and display indoor air quality using Bosch BME680 and/or Sensirion SGP30

Dependencies:   microbit

uses Bosch BME680 and/or Sensirion SGP30 sensors to measure indor air quality

sensors should be connected to BBC micro:bit using i2c

commands are received and data is being sent using uBit / nordic radio protocol

display ---

last line always indicates: - first dot: bme680 detected - second dot: sgp30 detected - third dot: sgp 30 setting humidity/temperature - fourth dor: sgp30 measuring - fith dot: bme680 measuring

the detect dots should be in a stable state (not blinking) the measuring dots should be blinking (constant light means: measurement failed)

if only one bme680 is present: - first 3 lines indicate gas resistence (air quality / more dots == worse quality) - fourth line indicates humidity level

if only sgp30 is present: - first two lines indicate SGP30 VOC level - third and fourth line indicate sgp30 CO2 level

if both sensors are present: - first line indicates SGP30 VOC level - second line line indicates sgp30 CO2 level - third line indicates bme680 gas resistence (air quality) - fourth line indicates bme 680 humidity level

buttons - B display state, switches betweeen - full bright - low light - display off

AB reset sgp30 baseline in non volatile storage

data logging -- during measurements the minimum and mximum values for each measured value (temperature, air pressure, humidity,gas resistance, VOC, CO2) are being stored in non volatile storage those (and the last measurement results) are being shown when btn A has been pressed

diff -r f9245fb53737 -r 544117df8c65 SGP30/sgp30.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SGP30/sgp30.h	Tue Dec 04 06:50:48 2018 +0000
@@ -0,0 +1,36 @@
+#include "mbed.h"
+#include "MicroBit.h"
+
+#include "i2c_callbacks.h"
+
+#ifndef SGP30_H
+#define SGP30_H
+
+
+class Sgp30 {
+    public:
+        Sgp30(I2cCallbacks *callbacks);
+        bool begin();
+        bool IAQmeasure(void);
+        bool setHumidity(uint32_t rel_humidity, uint32_t temperature);
+        
+        uint16_t TVOC;
+        uint16_t eCO2;
+        
+        uint16_t serialnumber[3];
+        
+    private:
+        I2cCallbacks *_callbacks;
+        uint8_t _i2caddr;
+        uint32_t _absolute_humidity;
+
+        bool IAQinit(void);
+        bool setHumidity(uint32_t absolute_humidity);
+        //void write(uint8_t address, uint8_t *data, uint8_t n);
+        //void read(uint8_t address, uint8_t *data, uint8_t n);
+        bool readWordFromCommand(uint8_t command[], uint8_t commandLength, uint16_t delay, uint16_t *readdata = NULL, uint8_t readlen = 0);
+        uint8_t generateCRC(uint8_t data[], uint8_t datalen);
+
+};
+
+#endif // SGP30_H
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