/*
* LM35DZ Temperature sensor using PCF8591
*
http://henrysbench.capnfatz.com/henrys-bench/arduino-voltage-measurements/pcf8591-adda-converter-arduino-tutorial-1-a-simple-analog-measurement/
*
* PCF8591
LM35ZD WeMos
*
SCL
---- D1(GPIO5)
*
SDA
---- D2(GPIO4)
*
A0
---- GND
*
A1
---- GND
*
A2
---- GND
*
VSS
---- GND
*
VDD
---- 3.3V
*
Vref
---- 3.3V
* AINT0 --- OUT
*
VCC ---- 3.3V
*
GND ---- GND
*/
#include "Wire.h"
#define PCF8591 (0x48) // I2C bus address
/*
pcf8591 The command byte is structured as follows.
7 6 5 4 3 2 1 0
0 X X X 0 X X X
| | | | | |
A B B C D D
A 0 D/A inactive
1 D/A active
B 00 single ended inputs
01 differential inputs
10 single ended and differential
11 two differential inputs
C 0 no auto inc
1 auto inc
D 00 select channel 0
01 select channel 1
10 select channel 2
11 select channel 3
*/
#define AIn0 0x00 // select single ended inputs from
channel 0
#define AIn1 0x01 // select single ended inputs from
channel 1
#define AIn2 0x02 // select single ended inputs from
channel 2
#define AIn3 0x03 // select single ended inputs from
channel 3
#define RefV 3.28
int RawValue0 = 0;
float Voltage = 0.0;
float temp_c = 0; // 摂氏値( ℃ )
void setup()
{
Wire.begin(4,5); // sda=4, scl=5
Serial.begin(9600);
}
void loop()
{
Wire.beginTransmission(PCF8591); // Start your
PCF8591
Wire.write(AIn0); // Tell it to make an Analog
Measurement from channel 0
Wire.endTransmission(); //
Wire.requestFrom(PCF8591, 2); // Get the Measured
Data
RawValue0=Wire.read(); // read PCF8591 (Dummy)
RawValue0=Wire.read(); // read PCF8591
// Serial.print(" RawValue0[PCF8591] = ");
// Serial.print(RawValue0);
Voltage = (RawValue0 * RefV )/ 255.0;
temp_c = Voltage * 100;
Serial.print(" Voltage[PCF8591] = ");
Serial.print(Voltage);
Serial.print(" temp_c[PCF8591] = ");
Serial.println(temp_c);
delay(500);
}
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