Diff: main.cpp

Revision:

0:97e328a3466a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Jun 04 10:14:54 2020 +0000
@@ -0,0 +1,49 @@
+#include "mbed.h"
+#include "TextLCD.h"
+DigitalInOut data_pin(p6); // Activate digital in as dht11 Pin
+DigitalOut pin5(p5); // Switch the fan on and off
+TextLCD lcd(p10, p12, p15, p16, p29, p30); // rs, e, d4-d7
+Timer tmr; //initialize timer
+uint64_t adat; // 64 bit variable for temporary data
+int i;
+void dht_read(void) {
+    data_pin.output(); // Set p6 as output
+    // Initialize measurement > 18 ms low
+    data_pin = 0;
+    wait_ms(20);
+    // After high and release the pin switch input mode
+    data_pin = 1;
+    data_pin.input();
+    // Wait until the end of 80 us low
+    while(!data_pin.read()) {}
+    // Wait until end of 80 us high
+    while(data_pin.read()) {}
+    // 40 bit, 40 read out cycle
+    for(i=0; i<40; i++) {
+        adat = adat << 1; // Shift for new number
+        tmr.stop(); // Stop timer if runs
+        tmr.reset();  // Reset timer
+        // Wait until pin
+        while(!data_pin.read()) {}          
+        tmr.start();            
+        while(data_pin.read()) {}
+        // If DHT11 HIGH longer than 40 micro seconds (hopefully 70 us)
+        if(tmr.read_us() > 40) {
+            // bit is 1
+            adat++;
+        }
+    }
+}
+int main() {
+    while(1) {
+            adat = 0;
+            dht_read(); // Call the function   
+            int abc = (adat & 0x0000000000ff0000) >> 16;            
+            lcd.printf("Temperature:\n");
+            lcd.printf("%d",abc);     // Temperature       
+            if(abc > 20) pin5 = 1;   // Fan is ON
+            else pin5 = 0;   //Fan is OFF
+            wait(2); // Wait 2 sec till continue.
+            lcd.cls(); // Clear the screen
+    }
+}
\ No newline at end of file