Revision 0:5e44a7bb06df, committed 2021-06-01

Comitter:

alexafer

Date:

Tue Jun 01 16:19:33 2021 +0000

Commit message:

for the black mbed

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/C12832.lib	Tue Jun 01 16:19:33 2021 +0000
@@ -0,0 +1,1 @@
+https://os.mbed.com/users/askksa12543/code/C12832/#990d5eec2ef6

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Jun 01 16:19:33 2021 +0000
@@ -0,0 +1,118 @@
+#include "mbed.h"
+#include "C12832.h"
+
+// defines msg
+#define SOS 0xff
+#define INIT 0xfe
+#define END 0xfd
+#define OK 0xfc
+
+C12832 lcd(p5, p7, p6, p8, p11);
+
+//pc mbed USB Slave function
+// connect mbed to pc USB
+RawSerial pc(USBTX, USBRX);
+//mbed LED
+DigitalOut led1(LED1);
+
+AnalogIn sensorMQ2(p17);
+CAN can(p30, p29);
+
+//constants
+const int numReadings = 500;
+
+//MQ2
+const float airRatioMQ2 = 10.0;
+const float slopeMQ2 = -0.4687;
+const float interceptMQ2 = 1.3969;
+
+//globals for the sensor readings
+float mq2sensorPPM = 0;
+
+//globals for the R0 values
+float r0MQ2 = 0.83142;
+
+
+//gloabals for alarm values
+float alarmMQ2 = 20.0;
+
+float calculateR0(AnalogIn s, float ratio) {
+        float sensor_volt;
+        float rs;
+        float sensorValue = 0.0;
+        float r0;
+
+        //take 500 sensor readings and add them together
+        for(int i = 0; i < numReadings; i++) {
+            sensorValue = sensorValue + s.read();
+        }
+
+        sensorValue = sensorValue/numReadings;//average sensor value
+        sensor_volt = sensorValue * 3.3;
+        rs = ((3.3-sensor_volt)/sensor_volt);
+        r0 = rs/ratio;
+        pc.printf("RO VALUE: %f \n\n", r0);
+        return r0;
+}
+
+float determinePPM(AnalogIn sensor, float R0, float m, float b) {
+        //Slope and y-intercept of ppm graph line, and R0 from previous calculations
+        float voltage = sensor.read() * 3.3;
+        float RS_gas = ((3.3-voltage)/voltage);
+        float ppmRatio = RS_gas/R0;
+        float ppm_log = (log10(ppmRatio)-b)/m;
+        float ppm = pow(10, ppm_log);
+        if(ppm<0){
+            ppm = 0.0;
+        }
+        if(ppm>10000){
+            ppm = 10000;
+        }
+        return ppm;
+}
+
+void sendInfo()
+{
+    char temp = 0;
+    led1 = !led1;
+    while(pc.readable()) {
+        temp = pc.getc();
+        if (temp == 'w')
+        {
+            pc.printf("{\"MQ2\":%f}\n", mq2sensorPPM);
+        }
+    }
+}
+
+// main() runs in its own thread in the OS
+int main() {
+    //Uncomment if we want to reset R0 from default to our environment
+    r0MQ2 = calculateR0(sensorMQ2, airRatioMQ2);
+
+    pc.attach(&sendInfo, Serial::RxIrq);
+    pc.baud(9600);
+
+    char msg;
+
+    while (1) {
+
+        mq2sensorPPM = determinePPM(sensorMQ2, r0MQ2, slopeMQ2, interceptMQ2);
+        lcd.cls();
+        lcd.locate(0,3);
+        lcd.printf("MQ2 value: %f", mq2sensorPPM);
+        if(mq2sensorPPM>alarmMQ2) {
+          msg = SOS ;
+          if (can.write(CANMessage(1337, &msg, 1))) {
+            pc.printf("Message sent: %d\n", (int)msg);
+            lcd.locate(0,15);
+            lcd.printf("threshold!");
+          }
+        } else {
+          msg = OK;
+          if (can.write(CANMessage(1337, &msg, 1))) {
+            pc.printf("Message sent: %d\n", (int)msg);
+          }
+        }
+        wait(0.1);
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Tue Jun 01 16:19:33 2021 +0000
@@ -0,0 +1,1 @@
+https://os.mbed.com/users/mbed_official/code/mbed/builds/65be27845400
\ No newline at end of file