Revision 0:58ee8a917618, committed 2014-08-18

Comitter:

vrabec

Date:

Mon Aug 18 18:01:09 2014 +0000

Child:

1:1a0ca36b6230

Commit message:

Initial commit

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BH1750.cpp	Mon Aug 18 18:01:09 2014 +0000
@@ -0,0 +1,72 @@
+/*
+
+This is a library for the BH1750FVI (GY-30) Digital Light Sensor
+breakout board.
+
+The board uses I2C for communication. 2 pins are required to
+interface to the device and in most cases also pull up resistors.
+
+Datasheet:
+http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1750fvi-e.pdf
+
+Inspired by Christopher Laws, March, 2013.
+Written by Michal Stehlik, August, 2014.
+
+*/
+
+#include "BH1750.h"
+
+BH1750::BH1750(PinName sda, PinName scl) : i2c(sda,scl)
+{
+    rawDataBuffer[0] = 0;
+    rawDataBuffer[1] = 0;
+    status = -1;
+}
+
+void BH1750::init(char mode)
+{
+    configure(mode);
+}
+
+
+void BH1750::configure(char mode)
+{
+    char data[1];
+    switch (mode) {
+        case BH1750_CONTINUOUS_HIGH_RES_MODE:
+        case BH1750_CONTINUOUS_HIGH_RES_MODE_2:
+        case BH1750_CONTINUOUS_LOW_RES_MODE:
+        case BH1750_ONE_TIME_HIGH_RES_MODE:
+        case BH1750_ONE_TIME_HIGH_RES_MODE_2:
+        case BH1750_ONE_TIME_LOW_RES_MODE:
+            data[0] = mode;
+            status = i2c.write(BH1750_I2CADDR, data, sizeof(data), false);
+            wait_ms(10);
+            break;
+        default:
+            break;
+    }
+}
+
+
+float BH1750::readIntesity(void)
+{
+    status = i2c.read(BH1750_I2CADDR, rawDataBuffer, 2, false);
+    if(status != 0) {
+        return -1;
+    }
+    //success
+    float result = 0;
+    result = ((rawDataBuffer[0]<<8)|rawDataBuffer[1])/1.2;
+    return result;
+}
+
+int BH1750::getStatus(void)
+{
+    return status;
+}
+
+char* BH1750::getRawData(void)
+{
+    return rawDataBuffer;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BH1750.h	Mon Aug 18 18:01:09 2014 +0000
@@ -0,0 +1,123 @@
+/*
+
+This is a library for the BH1750FVI (GY-30) Digital Light Sensor
+breakout board.
+
+The board uses I2C for communication. 2 pins are required to
+interface to the device and in most cases also pull up resistors.
+
+Datasheet:
+http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1750fvi-e.pdf
+
+Inspired by Christopher Laws, March, 2013.
+Written by Michal Stehlik, August, 2014.
+
+*/
+
+#ifndef BH1750_h
+#define BH1750_h
+
+#include "mbed.h"
+
+#define BH1750_I2CADDR 0x46
+
+// No active state
+#define BH1750_POWER_DOWN 0x00
+
+// Wating for measurment command
+#define BH1750_POWER_ON 0x01
+
+// Reset data register value - not accepted in POWER_DOWN mode
+#define BH1750_RESET 0x07
+
+// Start measurement at 1lx resolution. Measurement time is approx 120ms.
+#define BH1750_CONTINUOUS_HIGH_RES_MODE  0x10
+
+// Start measurement at 0.5lx resolution. Measurement time is approx 120ms.
+#define BH1750_CONTINUOUS_HIGH_RES_MODE_2  0x11
+
+// Start measurement at 4lx resolution. Measurement time is approx 16ms.
+#define BH1750_CONTINUOUS_LOW_RES_MODE  0x13
+
+// Start measurement at 1lx resolution. Measurement time is approx 120ms.
+// Device is automatically set to Power Down after measurement.
+#define BH1750_ONE_TIME_HIGH_RES_MODE  0x20
+
+// Start measurement at 0.5lx resolution. Measurement time is approx 120ms.
+// Device is automatically set to Power Down after measurement.
+#define BH1750_ONE_TIME_HIGH_RES_MODE_2  0x21
+
+// Start measurement at 1lx resolution. Measurement time is approx 120ms.
+// Device is automatically set to Power Down after measurement.
+#define BH1750_ONE_TIME_LOW_RES_MODE  0x23
+
+/**
+* @code
+* #include "mbed.h"
+* #include "BH1750.h"
+*
+* BH1750 lightSensor(I2C_SDA, I2C_SCL);
+* Serial pc(SERIAL_TX, SERIAL_RX);
+*
+* int main() 
+* {
+*    lightSensor.init();
+*
+*    while(1) {
+*        pc.printf("Light intensity: %.4f Lux\r\n", lightSensor.readIntesity());
+*        wait(5);
+*    }
+* }
+* @endcode
+*/
+
+class BH1750
+{
+public:
+    /**
+    * @param sda
+    * @param scl
+    */
+    BH1750(PinName sda, PinName slc);
+
+    /**
+    * Initialize sensor with specified mode.
+    * Default mode is set to BH1750_CONTINUOUS_HIGH_RES_MODE.
+    * @param mode of sensor operation.
+    */
+    void init(char mode = BH1750_CONTINUOUS_HIGH_RES_MODE);
+
+    /**
+    * Configure sensor with specified mode.
+    * This function is called also in init(char);
+    * @param mode of sensor operation.
+    */
+    void configure(char mode);
+
+    /**
+    * Read light intensity.
+    * In addition also error code and raw data are filled.
+    * @return light intensity in Lux.
+    */
+    float readIntesity(void);
+
+    /**
+    * Get raw data obtained after sucessfull executing of readIntesity(void).
+    * @return unprocessed raw data readed from sensor.
+    */
+    char* getRawData(void);
+
+    /**
+    * @returns
+    *     0 no error.
+    *     !=0 I2C error code.
+    */
+    int getStatus(void);
+
+private:
+    I2C i2c;
+    char rawDataBuffer[2];
+    int status;
+};
+
+#endif