i2c hello world

ESP8266/.vscode/settings.json

@@ -1,4 +1,18 @@
 {
     "C_Cpp.clang_format_fallbackStyle": "Visual Studio",
-    "C_Cpp.clang_format_style": "{ BasedOnStyle: LLVM, UseTab: Never, IndentWidth: 4, TabWidth: 4}"
+    "C_Cpp.clang_format_style": "{ BasedOnStyle: LLVM, UseTab: Never, IndentWidth: 4, TabWidth: 4}",
+    "files.associations": {
+        "array": "cpp",
+        "*.tcc": "cpp",
+        "deque": "cpp",
+        "list": "cpp",
+        "string": "cpp",
+        "unordered_map": "cpp",
+        "vector": "cpp",
+        "string_view": "cpp",
+        "memory": "cpp",
+        "random": "cpp",
+        "initializer_list": "cpp",
+        "ranges": "cpp"
+    }
 }

ESP8266/src/main.cpp

@@ -2,6 +2,7 @@
 #include <ESP8266WiFi.h>
 #include <PubSubClient.h>
 #include <LiquidCrystal_I2C.h>
+#include <Wire.h>
 
 #include <credentials.hpp>
 
@@ -36,6 +37,10 @@ void mqttCallback(char *topic, byte *payload, unsigned int length) {
         lcd.clear();
         lcd.setCursor(0, 0);
         lcd.printf("%s", message);
+    } else if (!strcmp(topic, ROOT_TOPIC "/i2c/set")) {
+        Wire.beginTransmission(0x3F);
+        Wire.printf("%s", message);
+        Wire.endTransmission();
     } else {
         // If topic is not recognized, exit without publishing to /get
         Serial.printf("Unrecognized topic %s\n", topic);
@@ -109,6 +114,7 @@ void connectEthernet() {
     SPI.setBitOrder(MSBFIRST);
     SPI.setDataMode(SPI_MODE0);
     SPI.setFrequency(4000000);
+
     uint8_t macaddr[6];
     int present = ethernet.begin(WiFi.macAddress(macaddr));
     if (!present) {
@@ -132,6 +138,7 @@ void connectEthernet() {
 }
 
 void setup() {
+    delay(5000);
     pinMode(LED_BUILTIN, OUTPUT);
     Serial.begin(921600);
     Serial.println();
@@ -185,4 +192,14 @@ void setup() {
     Serial.println(settopic);
 }
 
-void loop() { client.loop(); }
+uint8_t sensorData[4];
+
+void loop() { 
+    client.loop();
+    Wire.requestFrom(0x3F, 4);
+    size_t bytesRead = Wire.readBytes(sensorData, 4);
+    if(bytesRead){
+        client.publish(ROOT_TOPIC "/sensor/get", sensorData, bytesRead, false);
+    }
+    delay(100);
+}