Adding the folder with the drivers for the sensors HTU21D and BD1750.

7-sensors/BH1750_C.c

@@ -0,0 +1,50 @@
+#include <stdlib.h>
+#include <stdio.h> //to print error
+#include <fcntl.h> 
+
+#include <unistd.h> //header file for standard I2c send and receive commands
+#include <sys/ioctl.h> //setup I2c devices
+#include <linux/i2c-dev.h> //definitions and structures 
+#include <i2c/smbus.h> //smbus commands
+
+#include "BH1750_H.h"
+
+//Declarations of functions
+// Brightness:
+int get_lux(int fd, double *lux){
+    
+    // Establish the direction of the slave
+    if (ioctl(fd, I2C_SLAVE, BH1750_ADDR) < 0){
+        perror("Error to stablish the direction of I2C");
+        //close(fd);
+        return 1;
+    }
+
+    // Send the command for the mesaurment 
+    if(i2c_smbus_write_byte(fd, BH1750_OTHR) < 0){
+        perror("Failed to send the command for mesaurment ");
+        //close(fd);
+        return 1;
+    }
+
+    usleep(180000);
+
+	char buffer[2];
+	__s32 res = i2c_smbus_read_i2c_block_data(fd, 0x00, sizeof(buffer), buffer);
+	if (res != 2){
+		perror("Error -1: Failed to read from the device");
+        return 1;
+	}
+	*lux    = ((buffer[0] << 8) | buffer[1]) / 1.2;
+	return 0;
+}
+
+// Reset Sensor 
+/*int reset_BH1750(int fd){
+	if(0 > ioctl(fd, I2C_SLAVE, BH1750_ADDR)){
+		perror("Error -2: Failed to reset");
+		return -2;
+	}
+	i2c_smbus_write_byte(fd, BH1750_RESET);
+	return 0;
+}*/

7-sensors/BH1750_H.h

@@ -0,0 +1,17 @@
+#ifndef BH1750_h     //Definicion del archivo para header
+#define BH1750_h
+
+#define BH1750_ADDR 0x23	//Definition of sensor address direction 
+
+//Commands for reading of temperature or humidity 
+#define BH1750_PON	    0x01 //Command for power on 
+#define BH1750_OTHR	    0x20 //Command for One Time H-Resolution
+#define BH1750_RESET	0xFE //Command for Reset the sensor
+
+//Function declarations
+// Get the brightness:
+int get_lux(int fd, double *lux);
+// Reset:
+int reset_BH1750(int fd);
+
+#endif

7-sensors/HTU21D.c

@@ -0,0 +1,49 @@
+#include <stdlib.h>
+#include <stdio.h> //to print error 
+
+#include <unistd.h> //header file for standard I2c send and receive commands
+#include <sys/ioctl.h> //setup I2c devices
+#include <linux/i2c-dev.h> //definitions and structures 
+#include <i2c/smbus.h> //smbus commands
+
+#include "HTU21D_H.h"
+
+//Declarations of functions
+// Temperature:
+int get_temp(int fd, double *temp){
+	reset_sensor(fd);
+	char buffer[3];
+	__s32 res = i2c_smbus_read_i2c_block_data(fd, HTU21D_TEMP, sizeof(buffer), buffer);
+	if (res < 0){
+		perror("Error -1: Failed to read from the device");
+		return -1;
+	}
+	*temp = -46.85+175.72*(buffer[0]*256+buffer[1])/65536.0;
+	return 0;
+}
+
+// Humidity 
+//int get_hum(int fd, double *hum);
+int get_hum(int fd, double *hum){
+	reset_sensor(fd);
+	char buffer[3];
+	__s32 res = i2c_smbus_read_i2c_block_data(fd, HTU21D_HUM, sizeof(buffer), buffer);
+	if ( res < 0 ){
+		perror("Error -3: Failed to read humidity ");
+		return -1;
+	}
+	*hum = -6+125*(buffer[0]*256+buffer[1])/65536.0;
+	return 0;
+}
+
+// Reset Sensor 
+int reset_sensor(int fd){
+	if(0 > ioctl(fd, I2C_SLAVE, HTU21D_ADDR)){
+		perror("Error -2: Failed to reset");
+		return -2;
+	}
+	i2c_smbus_write_byte(fd, HTU21D_RESET);
+	return 0;
+}
+
+

7-sensors/HTU21D_H.h

@@ -0,0 +1,19 @@
+#ifndef HTU21D_H     //Definicion del archivo para header
+#define HTU21D_H
+
+#define HTU21D_ADDR 0x40	//Definition of sensor address direction 
+
+//Commands for reading of temperature or humidity 
+#define HTU21D_TEMP	    0xE3
+#define HTU21D_HUM	    0xE5
+#define HTU21D_RESET	0xFE
+
+//Function declarations
+// Temperature:
+int get_temp(int fd, double *temp);
+// Humidity:
+int get_hum(int fd, double *hum);
+// Reset:
+int reset_sensor(int fd);
+
+#endif

7-sensors/main.c

@@ -0,0 +1,86 @@
+/*Example code using Htu21d */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+//additional libraries:
+#include <fcntl.h>
+
+#include "HTU21D_H.h"
+#include "BH1750_H.h"
+#include <errno.h>
+
+#define I2C_PATH "/dev/i2c-%d"
+#define I2C_PORT_2 2
+#define I2C_PORT_1 1
+
+#define HTU21D_json_path "/home/debian/CODIGOS/8-react-ui-sensors/ui/HTU21D.json"
+#define BH1750_json_path "/home/debian/CODIGOS/8-react-ui-sensors/ui/BH1750.json"
+int sensor;
+
+int main() {
+	//printf("Select wich sensor would you like to get data: 1 -> HTU21D 2 -> BH1750 \n");
+	//scanf("%d", &sensor);
+	//sensor = 2;
+	while (1) {
+		//if (sensor == 1){
+		char filePath[99];
+		snprintf(filePath, sizeof(filePath), I2C_PATH, I2C_PORT_2);
+    	   	int fd = open(filePath, O_RDWR);
+		//to do.... complete the structure for the cases when we cant open the file
+		if(fd < 0){
+			fprintf(stderr, "Error: Unable to access HTU21D sensor: %s \n ", strerror(errno));
+			exit(-1);
+		}
+
+		double Temperature = 10;
+		double Humidity    =  0;
+		if((get_temp(fd, &Temperature)<0) || (get_hum(fd, &Humidity)<0)){
+				fprintf(stderr, "Error -404: Cant do the messaurment \n ");
+				exit(-1);
+		}
+    	    //printf("Temperature : %5.2f  <20>C\n", Temperature);
+		//printf("Humidity    : %5.2f  % \n", Humidity);
+		FILE *archivo = fopen(HTU21D_json_path, "w");
+		if (archivo == NULL){
+			perror("The file can not open ");
+			return -1;
+		} else{
+			fprintf(archivo, "{\"Temperature\" : %5.2f , \"Humidity\" : %5.2f}", Temperature, Humidity);
+		}
+		fclose(archivo);
+		printf ("{\"Temperature\" : %5.2f , \"Humidity\" : %5.2f}", Temperature, Humidity);
+
+		//} else if (sensor == 2){
+		//char filePath[99];
+		//snprintf(filePath, sizeof(filePath), I2C_PATH, I2C_PORT_1);
+    	//int 
+			fd = open(filePath, O_RDWR);
+		//to do.... complete the structure for the cases when we cant open the file
+		if(fd < 0){
+			fprintf(stderr, "Error: Unable to access HTU21D sensor: %s \n ", strerror(errno));
+			exit(-1);
+		}
+
+		double Bright = 0;
+		if((get_lux(fd, &Bright) < 0)){
+				fprintf(stderr, "Error -404: Cant do the messaurment \n ");
+				exit(-1);
+		}
+    	    //printf("Temperature : %5.2f  <20>C\n", Temperature);
+		//printf("Humidity    : %5.2f  % \n", Humidity);
+		FILE *archivo_1 = fopen(BH1750_json_path, "w");
+		if (archivo_1 == NULL){
+			perror("The file can not open ");
+			return -1;
+		} else{
+			fprintf(archivo_1, "{\"Brightness\" : %5.2f }", Bright);
+		}
+		fclose(archivo_1);
+		printf ("{\"Brightness\" : %5.2f }\n", Bright);
+		//}
+		usleep(2000000);
+	}	
+	return 0;	
+}