Diff: main.cpp

Revision:

0:28f2dba63d6c

Child:

1:011f0bdaa7f5

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Jul 17 13:44:11 2022 +0000
@@ -0,0 +1,100 @@
+/*----------------------------------------------------------
+State of a fictional IoT-enabled Ice cream machine
+The machine runs with an STM32F4 MCU; The Nucleo-F410RB was chosen as the device for implementation, it has serial communication, several digital outputs and 16 channel 12-bit ADC
+
+Operation: Ice cream dispenser arm sensor provides 0-3.3 V (assumed based on operating voltage 
+    of MCU) to one ADC pin on STM32F4 MCU. Voltage is based on position of dispenser arm. 
+- voltage > 1.65V implies the arm is pressed down 
+- voltage < 1.65V implies the arm is released 
+To prevent rapid switching, hysteresis is introduced with a count function, if arm has been pressed down for more than 5 seconds, the digital output will go high.
+
+Requirements:
+1. Read ADC value and print over serial port
+2. Digital output pin high if voltage>1.65V
+3. Digital output pin low if voltage <1.65V
+
+Assumptions:
+1. The code can run at a low speed as ice cream machines do not dispense ice cream quickly 
+2. Low accuracy and low resolution due to nature of ice cream machine dispensing arms
+
+Additional features
+1. Temperature of ice cream mixture is important, assume temperature sensor can provide analogue 
+    voltage to MCU
+2. Level of ice cream mix in machine is important, assume a sensor can detect when the mixture drops 
+    below a certain level, also be analogue voltage sensor output
+
+ADC data on MCU: 
+Value from 0.0 to 1.0, depending on input voltage between 0.0V and 
+3.3V; ADC default settings
+------------------------------------------------------------*/
+#include "mbed.h"
+Ticker readADC;     //Allows timed interval of reading data on ADC lines
+
+//Serial pc(USBTX, USBRX); //default settings: 9600 8N1
+Serial device(D8, D2);  // tx, rx, default settings: 9600 8N1
+
+AnalogIn DispArmIn(A0); //ADC input from dispensing arm
+AnalogIn TempIn(A1);    //ADC input from temperature sensor
+AnalogIn LevelIn(A2);   // ADC input from sensor detecting level
+
+float DispArm_data;     //Dispenser arm data
+float Temp_data;        //Temperature data
+float Level_data;       //Mixture level data
+bool ADC_ready;         //Indicate data has been read
+int counter;
+
+DigitalOut dout(A4);  //Digital output to indicate if dispensing arm has crossed the halfway mark
+DigitalOut led(LED2);   //Digital output for general use on LED
+
+void ReadAnalog()
+{
+//Assume default AnalogIn read settings
+    DispArm_data = DispArmIn;
+    Temp_data  = TempIn;
+    Level_data = LevelIn;
+    
+    if (DispArm_data>0.5f) //Add hysteresis with count function, to prevent rapid switching
+    {//Trigger output pin; Add this section here as it is one of the critical requirements.
+        counter++;
+        if(counter>5)
+        { 
+            dout = 1;  //Arm is pressed down
+            counter=0;
+        } else{}
+    }
+    else {
+         dout=0;    //Arm is released
+         counter=0;
+    }
+    ADC_ready=1;    //ADC have been read
+}
+
+int main() 
+{
+    //Initialise variables here
+    ADC_ready=0;
+    counter=0;    
+    DispArm_data = 0.0;
+    Temp_data  = 0.0;
+    Level_data = 0.0;
+    readADC.attach(&ReadAnalog, 0.5);   // the address of the function to be attached and the interval (2 seconds)
+    device.printf("\nIce cream machine state:\n");
+    
+    while (1) {
+        if (ADC_ready)
+        {
+           //pc.printf("%f \n\r",ADCdata);
+            device.printf("Dispenser arm %f \n\r",DispArm_data); 
+            if(Temp_data>0.7f)
+            {   
+                device.printf("Ice cream mixture not cooling: %f \n\r",Temp_data); 
+            }
+            if (Level_data<0.3f)
+            {
+                device.printf("Ice cream mixture level low: %f \n\r",Level_data); 
+            }
+            ADC_ready=0;
+        } else {}
+        wait (0.2f);
+    }
+}