Diff: ACS712.h

Revision:

13:671d602e700e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ACS712.h	Mon Oct 08 16:11:17 2018 +0000
@@ -0,0 +1,93 @@
+#include <mbed.h>
+/** A Hall-Effect sensor for measuring current levels in a given path
+ *
+ * Can be used as a current detector
+ *
+ * Example:
+ * @code
+ * // Periodically read current levels in a circuit and
+ * // send output to PC terminal
+ *
+ * #include "mbed.h"
+ * #include "ACS712.h"
+ *
+ * // Connect the sensor analog output pin to mbed's AnalogIn pin
+ * ACS712 dev(p18);
+ * // Connect mbed to pc's USB port
+ * Serial pc(USBTX, USBRX);
+ *
+ * int main() {
+ *      pc.printf("Sensor Log: \n\n\r");
+ *      while (1) {
+ *          // Read current from sensor and output to pc terminal
+ *          pc.printf("Sensor Value: %2.2f A\n\r", dev);
+ *          wait(0.200);
+ *      }
+ * }
+ * @endcode
+ */
+ 
+class ACS712 { 
+    
+    public:
+        /** Create a hall-effect sensor of the specified type
+         *
+         * @param _pin mbed AnalogIn pin where the analog output of sensor is connected
+         * @param voltDivRatio resistor voltage division ratio at output of the sensor
+         * @param type type of ACS712 sensor used
+         *
+         * @note Supported types of sensors:
+         */
+        ACS712(PinName _pin, float voltDivRatio = 1, short type = 5);
+        
+        /** Read the value of the measured current in amps
+         *
+         * @return current value in amps
+         */
+        float read();
+        ACS712& operator=(const ACS712&);
+        
+        /** Read the value of the measured current in amps
+         *  Allows the ACS712 object to be used in a float context
+         * 
+         * @return current value in amps
+         */
+        operator float() { return read(); }
+        
+    private:
+        AnalogIn sensor;
+        float translate(float);
+        float ratio;
+        short type;
+
+};
+
+ACS712::ACS712(PinName _pin, float voltDivRatio, short sensorType) : sensor(_pin){
+    ratio = voltDivRatio;
+    type = sensorType;    
+}
+
+float ACS712::translate(float val){
+    switch(type){
+        case 5: 
+            return (val*ratio - 2.46*ratio)/(.185*ratio);
+        case 20:
+            return (val*ratio - 2.46*ratio)/(.1*ratio);
+        case 30:
+            return (val*ratio - 2.46*ratio)/(.066*ratio);
+        default:
+            return 999;
+    }
+}
+
+
+float ACS712::read(){
+    return ACS712::translate((sensor) * 3.3);   
+}
+
+ACS712& ACS712::operator=(const ACS712& rhs){
+    sensor = rhs.sensor;
+    ratio = rhs.ratio;
+    type = rhs.type;
+    return *this;
+}