├── .github
    └── img.jpg
├── README.md
├── tea_server.ino
├── tealemetry.fcstd
└── tealemetry.stl


/.github/img.jpg:
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https://raw.githubusercontent.com/benjojo/tealemetry/9e93f93a92ae6827775c0660212910f751bd9cf6/.github/img.jpg


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/README.md:
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 1 | tealemetry, a tea coaster that has telemetry
 2 | ===
 3 | 
 4 | ![img](./.github/img.jpg)
 5 | 
 6 | While this is the code dump for a blog post I've done, you can find the ESP8266 code, a FreeCAD file, and the STL file for the coaster for 3d printing.
 7 | 
 8 | The required breakdown of stuff you need to make this is roughtly:
 9 | 
10 | 	* 1 ESP8266 12F
11 | 	* 1 MLX90616 ( with 5v compatible breakout board )
12 | 	* MicroUSB cable + Stable PSU to keep it going 24/7
13 | 
14 | 


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/tea_server.ino:
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  1 | #include <ESP8266WiFi.h>
  2 | #include <WiFiClient.h>
  3 | #include <ESP8266WebServer.h>
  4 | 
  5 | #include <Wire.h>
  6 | 
  7 | #define MLX90614_TA 0x06
  8 | #define MLX90614_TOBJ1 0x07
  9 | 
 10 | 
 11 | const char* ssid = "XXXXXXXXXXXXXXXXXXXX";
 12 | const char* password = "XXXXXXXXXXXXXXXXXXxx";
 13 | 
 14 | ESP8266WebServer server(80);
 15 | 
 16 | const int led = 13;
 17 | 
 18 | void handleRoot() {
 19 |   digitalWrite(led, 1);
 20 |   server.send(200, "text/plain", "hello from tea coaster!");
 21 |   digitalWrite(led, 0);
 22 | }
 23 | 
 24 | void handleNotFound(){
 25 |   digitalWrite(led, 1);
 26 |   String message = "File Not Found\n\n";
 27 |   message += "URI: ";
 28 |   message += server.uri();
 29 |   message += "\nMethod: ";
 30 |   message += (server.method() == HTTP_GET)?"GET":"POST";
 31 |   message += "\nArguments: ";
 32 |   message += server.args();
 33 |   message += "\n";
 34 |   for (uint8_t i=0; i<server.args(); i++){
 35 |     message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
 36 |   }
 37 |   server.send(404, "text/plain", message);
 38 |   digitalWrite(led, 0);
 39 | }
 40 | 
 41 | 
 42 | uint16_t read16(uint8_t addr, uint8_t i2c_addr){
 43 | uint16_t ret;
 44 | 
 45 | Wire.beginTransmission(i2c_addr); // start transmission to device 
 46 | Wire.write(addr); // sends register address to read from
 47 | Wire.endTransmission(false); // end transmission
 48 | 
 49 | Wire.requestFrom(i2c_addr, (uint8_t)3);// send data n-bytes read
 50 | ret = Wire.read(); // receive DATA
 51 | ret |= Wire.read() << 8; // receive DATA
 52 | 
 53 | uint8_t pec = Wire.read();
 54 | 
 55 | return ret;
 56 | }
 57 | 
 58 | 
 59 | float readTemp(uint8_t reg, uint8_t i2c_addr) {
 60 | float temp;
 61 | 
 62 | temp = read16(reg, i2c_addr);
 63 | temp *= .02;
 64 | temp -= 273.15;
 65 | return temp;
 66 | 
 67 | }
 68 | 
 69 | double readObjectTempC(uint8_t i2c_addr) {
 70 | return readTemp(MLX90614_TOBJ1, i2c_addr);
 71 | }
 72 | 
 73 | 
 74 | double readAmbientTempC(uint8_t i2c_addr) {
 75 | return readTemp(MLX90614_TA, i2c_addr);
 76 | }
 77 | 
 78 | uint32_t noquerycount;
 79 | 
 80 | 
 81 | void setup(void){
 82 |   Wire.begin(4,5);
 83 |   Wire.setClock(100000);
 84 | 
 85 |   pinMode(led, OUTPUT);
 86 |   digitalWrite(led, 0);
 87 |   Serial.begin(115200);
 88 |   WiFi.mode(WIFI_STA);
 89 |   WiFi.begin(ssid, password);
 90 |   Serial.println("");
 91 | 
 92 |   // Wait for connection
 93 |   while (WiFi.status() != WL_CONNECTED) {
 94 |     delay(500);
 95 |     Serial.print(".");
 96 |   }
 97 |   Serial.println("");
 98 |   Serial.print("Connected to ");
 99 |   Serial.println(ssid);
100 |   Serial.print("IP address: ");
101 |   Serial.println(WiFi.localIP());
102 | 
103 |   server.on("/", handleRoot);
104 | 
105 |   server.on("/metrics", [](){
106 |     digitalWrite(led, 1);
107 |     char page[512];
108 |     sprintf(page, "# HELP tea_mug_temp The point temp on the coaster.\n# TYPE tea_mug_temp gauge\ntea_mug_temp %f\n# HELP tea_ambient_temp the temp of the sensor.\n# TYPE tea_ambient_temp gauge\ntea_ambient_temp %f\n",readObjectTempC(0x5A), readAmbientTempC(0x5A));
109 |     server.send(200, "text/plain", page);
110 |     noquerycount = 0;
111 |     digitalWrite(led, 0);
112 |   });
113 | 
114 |   server.onNotFound(handleNotFound);
115 | 
116 |   server.begin();
117 |   Serial.println("HTTP server started");
118 | }
119 | 
120 | void loop(void){
121 |   server.handleClient();
122 |   delay(10);
123 |   noquerycount++;
124 |   if (WiFi.status() != WL_CONNECTED || noquerycount == 3000) {
125 |     ESP.restart();
126 |   }
127 | }
128 | 
129 | 


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/tealemetry.fcstd:
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https://raw.githubusercontent.com/benjojo/tealemetry/9e93f93a92ae6827775c0660212910f751bd9cf6/tealemetry.fcstd


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/tealemetry.stl:
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https://raw.githubusercontent.com/benjojo/tealemetry/9e93f93a92ae6827775c0660212910f751bd9cf6/tealemetry.stl


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