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

--- a/NvStore/nvstore.h	Wed Dec 05 11:41:21 2018 +0000
+++ b/NvStore/nvstore.h	Wed Dec 05 12:24:11 2018 +0000
@@ -15,9 +15,9 @@
         uint32_t getGasMax();
         uint32_t getGasMin();
         
-        void updateTemp(const uint32_t temperature);
-        uint32_t getTempMax();
-        uint32_t getTempMin();
+        void updateTemp(const int16_t temperature);
+        int16_t getTempMax();
+        int16_t getTempMin();
         
         void updatePress(const uint32_t pressure);
         uint32_t getPressMax();
@@ -37,14 +37,15 @@
                
     private:
         MicroBit* _uBit;
+        int16_t _tempMax, _tempMin;
         uint32_t _maxGas, _minGas,
-            _tempMax, _tempMin,
             _pressMax, _pressMin,
             _humMax, _humMin,
             _vocMax, _vocMin,
             _coMax, _coMin;
         
         uint32_t getStored(const char* key, const uint32_t defaultVal);
+        int16_t getStored16(const char * key, const int16_t defaultVal);
         void update(const uint32_t value, uint32_t* maxVal, uint32_t* minVal, const char* maxKey, const char* minKey);
 };