├── oled_temp2.ino
└── readme.md


/oled_temp2.ino:
--------------------------------------------------------------------------------
  1 | #include <max6675.h>
  2 | #include <Wire.h>
  3 | #include <Adafruit_SSD1306.h>
  4 | #include <Adafruit_GFX.h>
  5 | 
  6 | #define SCREEN_WIDTH 128 // OLED display width, in pixels
  7 | #define SCREEN_HEIGHT 64 // OLED display height, in pixels
  8 | 
  9 | // declarations for an SSD1306 OLED display connected to I2C (SDA, SCL pins)
 10 | #define OLED_RESET 16 // Reset pin # (or -1 if sharing Arduino reset pin)
 11 | TwoWire twi = TwoWire(1); // our own TwoWire instance on bus 1
 12 | Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &twi, OLED_RESET);
 13 | 
 14 | // declarations for the max6675 boards on SPI
 15 | int thermoDO = 19; //called SO on the max6675
 16 | int thermoCS = 23; //called CS on the max6675
 17 | int thermoCLK = 18; //called SCK on the max6675
 18 | 
 19 | int thermoCS2 = 5;
 20 | 
 21 | // the default setting is celsius
 22 | bool unit_F = false; //true = °F - false = °C
 23 |  
 24 | MAX6675 thermocouple(thermoCLK, thermoCS, thermoDO);
 25 | MAX6675 thermocouple2(thermoCLK, thermoCS2, thermoDO); 
 26 | 
 27 | void setup() {
 28 |   Serial.begin(115200);
 29 |   Serial.println("MAX6675 test");
 30 | 
 31 |   twi.begin(4,15);  // Needs to come before display.begin is used
 32 |   if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
 33 |     // Address 0x3C for 128x32
 34 |     Serial.println(F("SSD1306 allocation failed"));
 35 |     // for(;;); // Don't proceed, loop forever
 36 |   }
 37 | 
 38 |   display.clearDisplay();
 39 |   display.setTextSize(3);
 40 |   display.setTextColor(WHITE);
 41 |   display.setCursor(0,0);
 42 |   display.println("start");
 43 |   display.println("display..");
 44 |   display.display();
 45 | 
 46 |   delay(500);
 47 | }
 48 | 
 49 | // write data to the OLED
 50 | void Display_WRITE(){
 51 |   display.clearDisplay();
 52 |   display.setTextSize(2);
 53 |   display.setTextColor(WHITE);
 54 |   display.setCursor(0,0);
 55 |   display.print("ET ");
 56 |   if (unit_F) {
 57 |     display.println(thermocouple.readFahrenheit());
 58 |     display.print("BT ");
 59 |     display.println(thermocouple2.readFahrenheit());
 60 |     }
 61 |   else if (!unit_F) {
 62 |     display.println(thermocouple.readCelsius());
 63 |     display.print("BT ");
 64 |     display.println(thermocouple2.readCelsius());
 65 |   }
 66 |   display.display();
 67 | }
 68 | 
 69 | //Send Serial Data
 70 | void Command_WRITE(){
 71 |     Serial.print("0.00,");
 72 |     if (unit_F) {
 73 |         Serial.print(thermocouple.readFahrenheit());
 74 |         Serial.print(",");
 75 |         Serial.print(thermocouple2.readFahrenheit());
 76 |     }
 77 |     else if (!unit_F) {
 78 |         Serial.print(thermocouple.readCelsius());
 79 |         Serial.print(",");
 80 |         Serial.print(thermocouple2.readCelsius());
 81 |     }
 82 |     Serial.println(",0.00,0.00");
 83 | }
 84 | 
 85 | //Parsing Serial Commands
 86 | void handleSerialCommand(){   
 87 | 
 88 |    if (Serial.available()>0){
 89 |         String msg = Serial.readStringUntil('\n');
 90 | 
 91 |         if (msg.indexOf("CHAN;")== 0){  //Ignore this Setting
 92 |             Serial.print("#OK");
 93 |         }
 94 |         else if (msg.indexOf("UNITS;")== 0){
 95 | 
 96 |             if (msg.substring(6,7)=="F"){   //Change to Farenheit
 97 |                 unit_F = true;
 98 |                 Serial.println("#OK Farenheit");
 99 |             }
100 |             else if (msg.substring(6,7)=="C"){  //Change to Celsius
101 |                 unit_F = false;
102 |                 Serial.println("#OK Celsius");
103 |             }
104 | 
105 |         }
106 |         else if (msg.indexOf("READ")==0){   //Send Temps
107 |            Command_WRITE();
108 | 
109 |        }
110 |    }
111 | 
112 | }
113 | 
114 | 
115 | void loop()
116 | {
117 | 
118 |     handleSerialCommand();
119 |  
120 |     Display_WRITE();
121 | 
122 |     delay(500);
123 | }
124 | 


--------------------------------------------------------------------------------
/readme.md:
--------------------------------------------------------------------------------
 1 | ## ESP32 with OLED and MAX6675 to read thermocouples and function as TC4 for recording bean and environmental temperatures for Roastlogger and Artisan coffee roasting software ##
 2 | 
 3 | ### Boards used ###
 4 | ESP32:<br/>
 5 | http://www.lilygo.cn/prod_view.aspx?TypeId=50032&Id=1152&FId=t3:50032:3<br/>
 6 | ordered via: https://www.aliexpress.com/item/32824839148.html<br/>
 7 | 
 8 | MAX6675:<br/>
 9 | ordered via: https://www.aliexpress.com/item/1902975176.html<br/>
10 | 
11 | Thermocouples: <br/>(I've tried a few -- in addition to the ones that come with the MAX6675)<br/>
12 | ordered via: https://www.aliexpress.com/item/32848451468.html<br/>
13 | ordered via: https://www.aliexpress.com/item/32795229358.html<br/>
14 | 
15 | Pin map for above the ESP32 board:<br/>
16 | https://0.rc.xiniu.com/g1/M00/29/CB/CgAGTF1agBWASwmZAAF9zU1LNpY299.jpg<br/>
17 | ![picture alt](https://0.rc.xiniu.com/g1/M00/29/CB/CgAGTF1agBWASwmZAAF9zU1LNpY299.jpg "Pin map")
18 | 
19 | It's just a little code to use ttgo esp32 board with two max6675 and oled -- to work like a TC4 to artisan roasting software
20 | 


--------------------------------------------------------------------------------