Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 22 | jlesech | 1 | #include <OneWire.h> |
| 2 | |||
| 3 | // OneWire DS18S20, DS18B20, DS1822 Temperature Example |
||
| 4 | // |
||
| 5 | // http://www.pjrc.com/teensy/td_libs_OneWire.html |
||
| 6 | // |
||
| 7 | // The DallasTemperature library can do all this work for you! |
||
| 8 | // http://milesburton.com/Dallas_Temperature_Control_Library |
||
| 9 | |||
| 10 | OneWire ds(10); // on pin 10 |
||
| 11 | |||
| 12 | void setup(void) { |
||
| 13 | Serial.begin(9600); |
||
| 14 | } |
||
| 15 | |||
| 16 | void loop(void) { |
||
| 17 | byte i; |
||
| 18 | byte present = 0; |
||
| 19 | byte type_s; |
||
| 20 | byte data[12]; |
||
| 21 | byte addr[8]; |
||
| 22 | float celsius, fahrenheit; |
||
| 23 | |||
| 24 | if ( !ds.search(addr)) { |
||
| 25 | Serial.println("No more addresses."); |
||
| 26 | Serial.println(); |
||
| 27 | ds.reset_search(); |
||
| 28 | delay(250); |
||
| 29 | return; |
||
| 30 | } |
||
| 31 | |||
| 32 | Serial.print("ROM ="); |
||
| 33 | for( i = 0; i < 8; i++) { |
||
| 34 | Serial.write(' '); |
||
| 35 | Serial.print(addr[i], HEX); |
||
| 36 | } |
||
| 37 | |||
| 38 | if (OneWire::crc8(addr, 7) != addr[7]) { |
||
| 39 | Serial.println("CRC is not valid!"); |
||
| 40 | return; |
||
| 41 | } |
||
| 42 | Serial.println(); |
||
| 43 | |||
| 44 | // the first ROM byte indicates which chip |
||
| 45 | switch (addr[0]) { |
||
| 46 | case 0x10: |
||
| 47 | Serial.println(" Chip = DS18S20"); // or old DS1820 |
||
| 48 | type_s = 1; |
||
| 49 | break; |
||
| 50 | case 0x28: |
||
| 51 | Serial.println(" Chip = DS18B20"); |
||
| 52 | type_s = 0; |
||
| 53 | break; |
||
| 54 | case 0x22: |
||
| 55 | Serial.println(" Chip = DS1822"); |
||
| 56 | type_s = 0; |
||
| 57 | break; |
||
| 58 | default: |
||
| 59 | Serial.println("Device is not a DS18x20 family device."); |
||
| 60 | return; |
||
| 61 | } |
||
| 62 | |||
| 63 | ds.reset(); |
||
| 64 | ds.select(addr); |
||
| 65 | ds.write(0x44,1); // start conversion, with parasite power on at the end |
||
| 66 | |||
| 67 | delay(1000); // maybe 750ms is enough, maybe not |
||
| 68 | // we might do a ds.depower() here, but the reset will take care of it. |
||
| 69 | |||
| 70 | present = ds.reset(); |
||
| 71 | ds.select(addr); |
||
| 72 | ds.write(0xBE); // Read Scratchpad |
||
| 73 | |||
| 74 | Serial.print(" Data = "); |
||
| 75 | Serial.print(present,HEX); |
||
| 76 | Serial.print(" "); |
||
| 77 | for ( i = 0; i < 9; i++) { // we need 9 bytes |
||
| 78 | data[i] = ds.read(); |
||
| 79 | Serial.print(data[i], HEX); |
||
| 80 | Serial.print(" "); |
||
| 81 | } |
||
| 82 | Serial.print(" CRC="); |
||
| 83 | Serial.print(OneWire::crc8(data, 8), HEX); |
||
| 84 | Serial.println(); |
||
| 85 | |||
| 86 | // convert the data to actual temperature |
||
| 87 | |||
| 88 | unsigned int raw = (data[1] << 8) | data[0]; |
||
| 89 | if (type_s) { |
||
| 90 | raw = raw << 3; // 9 bit resolution default |
||
| 91 | if (data[7] == 0x10) { |
||
| 92 | // count remain gives full 12 bit resolution |
||
| 93 | raw = (raw & 0xFFF0) + 12 - data[6]; |
||
| 94 | } |
||
| 95 | } else { |
||
| 96 | byte cfg = (data[4] & 0x60); |
||
| 97 | if (cfg == 0x00) raw = raw << 3; // 9 bit resolution, 93.75 ms |
||
| 98 | else if (cfg == 0x20) raw = raw << 2; // 10 bit res, 187.5 ms |
||
| 99 | else if (cfg == 0x40) raw = raw << 1; // 11 bit res, 375 ms |
||
| 100 | // default is 12 bit resolution, 750 ms conversion time |
||
| 101 | } |
||
| 102 | celsius = (float)raw / 16.0; |
||
| 103 | fahrenheit = celsius * 1.8 + 32.0; |
||
| 104 | Serial.print(" Temperature = "); |
||
| 105 | Serial.print(celsius); |
||
| 106 | Serial.print(" Celsius, "); |
||
| 107 | Serial.print(fahrenheit); |
||
| 108 | Serial.println(" Fahrenheit"); |
||
| 109 | } |