平台：Arduino
IDE：Arduino 1.6.7
BH1750FVI模块，基于IIC总线
程序模块流程描述：
1.驱动BH1750FVI，将获得的数据转化为整数型并存储（单位LX）
2.通过算法将LX转为EV值
3.构建光圈表和快门速度表，对照EV表进行查询
4.得到最合适的快门速度，依据ISO进行偏移，得到在对应光圈，ISO和光强下最终的快门速度（结果）
//主函数文件，包括了对BH1750的声明，测试平台为Arduino UNO，IIC接口为A4，A5.
//Base on BH1750 sensor modle
#include //IIC #include int BH1750address = 0x23; byte buff[2]; void setup() { Wire.begin(); Serial.begin(9600); } void loop()//MyBlgo:http://blog.sina.com.cn/u/3909624897, if you have some question
{ int i; uint16_t val = 0; BH1750_Init(BH1750address); delay(1000); if (2 == BH1750_Read(BH1750address)) { val = ((buff[0] << 8) | buff[1]) / 1.2; //Serial.println("=================================="); LuxToEV(val); EVandIrisToCountOutSpeed(); SerialPrint(); Serial.println(" "); Serial.print(val, DEC); Serial.println(" lux"); Serial.print("==================================");
// LuxToShutterSpeed(val); } delay(150); }
int BH1750_Read(int address) // {
int i = 0; Wire.beginTransmission(address); Wire.requestFrom(address, 2); while (Wire.available()) // { buff[i] = Wire.read(); // receive one byte i++; } Wire.endTransmission(); return i; }
void BH1750_Init(int address) { Wire.beginTransmission(address); Wire.write(0x10);//1lx reolution 120ms Wire.endTransmission();
}
//测光表函数文件，包含有转换EV数值，进行快门-光圈-EV表格筛选等函数
int H, E, T; //H = E x T;E = I x T; const int ISO[10] ={100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600}; int Iris , SpeedM = 0, R = 2 , M=0, I=1;//R is iris area number,M is speed area number,I is is number ,default is ISO 100 int Elux;//AS the balance reference of expose and lux; float EV; int i,j;//MyBlgo:http://blog.sina.com.cn/u/3909624897, if you have some question int EVSeries[14][11] = {//The matrix of EV,x is iris num,y is shutter speed num 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, }; float IrisR[11] = {1.0, 1.4, 2.0, 2.8, 4.0, 5.6, 8.0, 11.0, 16.0, 22.0, 32.0}; int Speed[14] = { 8000, 4000, 2000, 1000, 500, 250, 125, 60, 30, 15, 8, 4, 2 , 1 }; int CankaoLUX[18] = {2.5, 5, 10, 20, 40, 80, 160, 320, 640, 1280, 2560, 5120, 10240, 20480, 40960, 81920, 163840}; void LuxToEV(int lux) { for (i = 0; i < 18; i++) { if (lux > CankaoLUX[i] && lux < CankaoLUX[i + 1]) { EV = float((lux-CankaoLUX[i])/ (CankaoLUX[i+1]-CankaoLUX[i])) +i; Serial.print(EV); Serial.println("EV"); break; } } } void EVandIrisToCountOutSpeed() { for(i=1;i<14;i++) { if (EV== EVSeries[i][R-1]) { //Serial.println(EVSeries[i][R]); M = i-1;//Make M(the speed vs number) equal to count number; break; } } }
void SerialPrint() { Serial.print(" Iris:"); Serial.print(IrisR[R]); Serial.print(" Speed:1/"); Serial.print(Speed[13-M-I]);//The speed is 13-M and I(ISO number) Serial.println("s "); Serial.print(" ISO:"); Serial.print(ISO[I]); // Serial.print(SpeedM); }
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