I2C Communication with the particule sensor : SPS30

tags: flipper, I2C

This is an example code of I2C communication between a particulate matter sensor and the flipper board.

The particulate matter sensor is a Sensirion SPS30.

The sensor is wired on I2C1 communication bus so we will use Wire1 instance (if we were using I2C0 it would have been Wire instance, see flipper arduino bus references ). The i2C address of the SPS is 0x69 (see datasheet ).

Following code has been modified and adapted from this source.

1. Arduino code

#include "Wire.h" int Address = 0x69; // device address of SPS30 (fixed). byte w1, w2,w3; byte ND[60]; long tmp; float measure; void setup() { //enabling VDD_SW power rail to give 5V source to the dolfin board pinMode(SW_VDD_EN, OUTPUT); digitalWrite(SW_VDD_EN,HIGH); //enabling 5V_sensor power rail to switch on the sensor pinMode(EXP_36, OUTPUT); digitalWrite(EXP_36,HIGH); //enabling 3V3_SW power rail to pull the I2C bus up via the 10K resistors pinMode(SW_3V3_EN, OUTPUT); digitalWrite(SW_3V3_EN,HIGH); //wait for the power sources to be turned on delay(1000); Wire1.begin(); // Initiate the Wire1 instance Serial.begin(115200); delay(100); } void loop() { /* // RESET device delay(1000); SetPointer(0xD3, 0x04); delay(1000); */ //Start Measurement Wire1.beginTransmission(Address); Wire1.write(0x00); Wire1.write(0x10); Wire1.write(0x03); Wire1.write(0x00); uint8_t data[2]={0x03, 0x00}; Wire1.write(CalcCrc(data)); Wire1.endTransmission(); delay(10000); /* //Start Fan Cleaning Serial.println("clean"); Start fan cleaning SetPointer(0x56, 0x07); delay(12000); Serial.println("clean end"); delay(100); */ while(1){ Serial.println(" ---------- "); //Read data ready flag SetPointer(0x02, 0x02); Wire1.requestFrom(Address, 3); w1=Wire1.read(); w2=Wire1.read(); w3=Wire1.read(); if (w2==0x01){ //0x01: new measurements ready to read SetPointer(0x03,0x00); Wire1.requestFrom(Address, 60); for(int i=0;i<60;i++) { ND[i]=Wire1.read(); // for(int i=0;i<30;i++) { ND[i]=Wire.read(); //without Wire.h lib modification only first 5 values //Serial.print(i);Serial.print(": ");Serial.println(ND[i],HEX); } // Result: PM1.0/PM2.5/PM4.0,PM10[Î¼g/mÂ³] , PM0.5,PM1.0/PM2.5/PM4.0,PM10 [[#/cmÂ³], Typical Particle Size [Î¼m] for(int i=0;i<60;i++) { if ((i+1)%3==0) { byte datax[2]={ND[i-2], ND[i-1]}; //Serial.print("crc: ");Serial.print(CalcCrc(datax),HEX); //Serial.print(" "); Serial.println(ND[i],HEX); if(tmp==0) { tmp= ND[i-2]; tmp= (tmp<<8) + ND[i-1]; } else{ tmp= (tmp<<8)+ ND[i-2]; tmp= (tmp<<8) + ND[i-1]; //Serial.print(tmp,HEX);Serial.print(" "); measure= (*(float*) &tmp); Serial.print(measure); Serial.print(" "); tmp=0; } } } } Serial.println(""); delay(2000); } // Stop Meaurement // SetPointer(0x01, 0x04); } void SetPointer(byte P1, byte P2) { Wire1.beginTransmission(Address); Wire1.write(P1); Wire1.write(P2); Wire1.endTransmission(); } // from datasheet: byte CalcCrc(byte data[2]) { byte crc = 0xFF; for(int i = 0; i < 2; i++) { crc ^= data[i]; for(byte bit = 8; bit > 0; --bit) { if(crc & 0x80) { crc = (crc << 1) ^ 0x31u; } else { crc = (crc << 1); } } } return crc; }