heejeong koo / DHT_HW3

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Fork of DHT by jajn HA

Files at this revision

API Documentation at this revision

Revision 4:1e78a462b211, committed 2017-07-20

Comitter:
david8251
Date:
Thu Jul 20 09:04:07 2017 +0000
Parent:
2:df22ddf10d75
Child:
5:d69bf5f18bf8
Commit message:
DHT

Changed in this revision

DHT.cpp Show annotated file Show diff for this revision Revisions of this file 
--- a/DHT.cpp	Fri Aug 15 20:55:43 2014 +0000
+++ b/DHT.cpp	Thu Jul 20 09:04:07 2017 +0000
@@ -78,7 +78,7 @@
     DHT_io.output();
     DHT_io = 0;
     // only 500uS for DHT22 but 18ms for DHT11
-    (_DHTtype == 11) ? wait_ms(18) : wait(1);
+    (_DHTtype == 11) ? wait_ms(18) : wait(0.0005);
     DHT_io = 1;
     wait_us(30);
     DHT_io.input();
@@ -156,7 +156,7 @@
 
 float DHT::ReadHumidity()
 {
-    return _lastHumidity;
+    return _lastHumidity+30;
 }
 
 float DHT::ConvertCelciustoFarenheit(float const celsius)
@@ -179,7 +179,7 @@
     SUM += -1.3816e-7 * (pow(10, (11.344*(1-1/A0)))-1) ;
     SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ;
     SUM += log10(1013.246);
-    float VP = pow(10, SUM-3) * humidity;
+    float VP = pow(10, SUM-3) * (humidity);
     float T = log(VP/0.61078);   // temp var
     return (241.88 * T) / (17.558-T);
 }
@@ -187,14 +187,14 @@
 // delta max = 0.6544 wrt dewPoint()
 // 5x faster than dewPoint()
 // reference: http://en.wikipedia.org/wiki/Dew_point
-float DHT::CalcdewPointFast(float const celsius, float const humidity)
+/*float DHT::CalcdewPointFast(float const celsius, float const humidity)
 {
     float a = 17.271;
     float b = 237.7;
     float temp = (a * celsius) / (b + celsius) + log(humidity/100);
     float Td = (b * temp) / (a - temp);
     return Td;
-}
+}*/
 
 float DHT::ReadTemperature(eScale Scale)
 {