diff --git a/board.ino b/board.ino
index 2322323..17e9cf8 100644
--- a/board.ino
+++ b/board.ino
@@ -12,6 +12,7 @@ const int dummy = 0;
 const int ledPin = 13;
 
 const uint8_t WIDTH = 6;
+const uint8_t FULL_WIDTH = WIDTH * 2;
 const uint8_t HEIGHT = 4;
 
 
@@ -26,11 +27,12 @@ void setup()
 {
     // initialize the digital pin as an output.
     pinMode(ledPin, OUTPUT);
-    digitalWrite(ledPin, HIGH);
+    digitalWrite(ledPin, LOW);
 
     Serial.begin(115200);
     Serial3.setTX(20);
-    Serial3.begin(115200);
+    Serial3.setRX(7);
+    Serial3.begin(9600);
     //keyboard.setup();
 
     init_pins<WIDTH, HEIGHT>(ROW_PINS, COL_PINS);
@@ -44,29 +46,35 @@ void loop()
     while(true)
     {
         auto read_keys = read_pressed_keys(ROW_PINS, COL_PINS);
+#define IS_SLAVE
+#ifdef IS_SLAVE
+        auto bytes = coords_to_bytes(read_keys);
+        send_uart_bytes(bytes);
+        digitalWrite(ledPin, HIGH);
+        delay(10);
+#else
+        //auto read_keys = read_pressed_keys(ROW_PINS, COL_PINS);
+        auto read_bytes = read_uart_byte_stream<(WIDTH * HEIGHT)*2 + 1>();
+        auto decode_result = decode_coordinates_from_bytes<WIDTH * HEIGHT>(read_bytes);
+        if(decode_result.error != CoordsFromBytesError::SUCCESS)
+        {
+            Serial.println("Got invalid bytes");
+            continue;
+        }
+        digitalWrite(ledPin, HIGH);
+        Serial.println("Doing loop stuff");
+        auto other_read_keys = decode_result.keys;
 
         auto keymap = init_keymap<WIDTH, HEIGHT>(default_layout);
 
-        auto translated = translate_coordinates<WIDTH, HEIGHT>(read_keys, keymap);
+        auto translated = translate_coordinates<WIDTH, HEIGHT>(other_read_keys, keymap);
 
         auto keytypes = keycodes_to_keytypes<WIDTH * HEIGHT>(translated);
 
         auto packet = keytypes_to_packet<WIDTH*HEIGHT>(keytypes, old_packet);
         old_packet = packet;
 
-        //for(uint8_t i = 0; i < packet.keys.size(); ++i)
-        //{
-        //    set_key(i, packet.keys[i]);
-        //}
-        //for(uint8_t i = packet.keys.size(); i < KEYS_PER_PACKET; ++i)
-        //{
-        //    set_key(i, 0);
-        //}
-        //Keyboard.set_modifier(packet.modifiers);
-        //Keyboard.send_now();
-
-        //send_packet(packet);
-
-        send_coordinates(read_keys);
+        send_packet(packet);
+#endif
     }
 }
diff --git a/constants.h b/constants.h
index d278fc0..8f3f1c2 100644
--- a/constants.h
+++ b/constants.h
@@ -3,6 +3,6 @@
 
 #include <stdint.h>
 
-const uint8_t KEY_MESSAGE_START = 0xFE;
+const uint8_t KEY_MESSAGE_START = 0b10111101;
 const uint8_t KEY_MESSAGE_END = 0xFF;
 #endif
diff --git a/keyboard_arduino.h b/keyboard_arduino.h
index c9db900..abd3215 100644
--- a/keyboard_arduino.h
+++ b/keyboard_arduino.h
@@ -14,7 +14,6 @@ void init_pins(
         const BoundedArray<uint8_t, WIDTH> col_pins
     )
 {
-    digitalWrite(13, HIGH);
     for(uint8_t y = 0; y < HEIGHT; ++y)
     {
         pinMode(row_pins[y], OUTPUT);
@@ -23,8 +22,6 @@ void init_pins(
             pinMode(col_pins[x], INPUT_PULLUP);
         }
     }
-    
-    digitalWrite(13, HIGH);
 }
 
 
@@ -60,24 +57,18 @@ BoundedArray<KeyCoordinate, WIDTH*HEIGHT> read_pressed_keys(
 void set_key(const uint8_t index, const uint16_t key);
 void send_packet(const KeyPacket packet);
 
-template<size_t KEY_AMOUNT>
-void send_coordinates(const BoundedArray<KeyCoordinate, KEY_AMOUNT> coords)
+template<size_t BYTE_AMOUNT>
+void send_uart_bytes(const BoundedArray<uint8_t, BYTE_AMOUNT> bytes)
 {
-    //send the start byte
+    //Write the start byte
     Serial3.write(KEY_MESSAGE_START);
 
-    uint8_t checksum = 0;
-
-    for(size_t i = 0; i < coords.size(); ++i)
+    for(size_t i = 0; i < bytes.size(); ++i)
     {
-        checksum += coords[i].x + coords[i].y;
-        Serial3.write(coords[i].x);
-        Serial3.write(coords[i].y);
+        Serial3.write(bytes[i]);
     }
-    //Write the checksum
-    Serial3.write(checksum);
-    //Write an end byte
     Serial3.write(KEY_MESSAGE_END);
+    Serial3.flush();
 }
 
 
@@ -90,7 +81,7 @@ void send_coordinates(const BoundedArray<KeyCoordinate, KEY_AMOUNT> coords)
 template<size_t MAX_RECEIVED_BYTES>
 BoundedArray<uint8_t, MAX_RECEIVED_BYTES> read_uart_byte_stream()
 {
-    auto received_bytes = BoundedArray<KeyCoordinate, MAX_RECEIVED_BYTES>();
+    auto received_bytes = BoundedArray<uint8_t, MAX_RECEIVED_BYTES>();
 
     bool done = false;
     bool is_reading_keys = false;
@@ -98,8 +89,11 @@ BoundedArray<uint8_t, MAX_RECEIVED_BYTES> read_uart_byte_stream()
     while(!done)
     {
         uint8_t new_byte;
-        while(!Serial3.available())
-        {}
+        while(Serial3.available() < 1)
+        {
+            //Serial.println("Waiting for uart");
+        }
+        Serial.println("After loop");
 
         new_byte = Serial3.read();
 
diff --git a/keyboard_functional.h b/keyboard_functional.h
index 12cee0a..beebc4c 100644
--- a/keyboard_functional.h
+++ b/keyboard_functional.h
@@ -148,7 +148,7 @@ namespace Z
             result.push(array1[i]);
         }
 
-        for(size_t i = 0; i < array2.size(); i++)
+        for(size_t i = 0; i < array2.size(); ++i)
         {
             result.push(function(array2[i]));
         }
@@ -167,7 +167,7 @@ namespace Z
         )
     {
         auto result = BoundedArray<Keycode, WIDTH*HEIGHT>();
-        for(size_t i = 0; i < coordinates.size(); i++)
+        for(size_t i = 0; i < coordinates.size(); ++i)
         {
             result.push(map[coordinates[i].x][coordinates[i].y]);
         }
@@ -268,42 +268,88 @@ namespace Z
     }
 
 
+
+    /*
+      Translates a list of keyboard coordinates into a list of bytes that can
+      be sent over UART and decoded by the decode_coordinates_from_bytes function
+    */
+    template<size_t KEY_AMOUNT>
+    BoundedArray<uint8_t, KEY_AMOUNT * 2 + 1> coords_to_bytes(
+            BoundedArray<KeyCoordinate, KEY_AMOUNT> coords
+        )
+    {
+        auto result = BoundedArray<uint8_t, KEY_AMOUNT * 2 + 1>();
+        uint8_t checksum = 0;
+        for(size_t i = 0; i < coords.size(); ++i)
+        {
+            result.push(coords[i].x);
+            result.push(coords[i].y);
+
+            checksum += coords[i].x + coords[i].y;
+        }
+        result.push(checksum);
+        return result;
+    }
+
+
+    /*
+      Different things that can go wrong when translating bytes to coordinates
+    */
     enum class CoordsFromBytesError
     {
         SUCCESS,
         INVALID_AMOUNT_OF_BYTES,
         INVALID_CHECKSUM
     };
+    /*
+      Result type that is returned when translating bytes to coordinates
+    */
     template<size_t KEY_AMOUNT>
-    struct FromBytesResult
+    struct CoordsFromBytesResult
     {
         BoundedArray<KeyCoordinate, KEY_AMOUNT> keys;
         CoordsFromBytesError error;
 
-        FromBytesResult(CoordsFromBytesError error)
+        CoordsFromBytesResult(CoordsFromBytesError error)
         {
             this->error = error;
         }
-        FromBytesResult(BoundedArray<KeyCoordinate, KEY_AMOUNT> keys)
+        CoordsFromBytesResult(BoundedArray<KeyCoordinate, KEY_AMOUNT> keys)
         {
             this->keys = keys;
             this->error = CoordsFromBytesError::SUCCESS;
         }
     };
 
+    /*
+      Converts a stream of keyboard bytes into coordinates
+    */
     template<size_t KEY_AMOUNT>
-    FromBytesResult<KEY_AMOUNT> decode_coordinates_from_bytes(
+    CoordsFromBytesResult<KEY_AMOUNT> decode_coordinates_from_bytes(
             BoundedArray<uint8_t, KEY_AMOUNT * 2 + 1> bytes
         )
     {
+        auto result = BoundedArray<KeyCoordinate, KEY_AMOUNT>();
+
         if(bytes.size() % 2 != 1)
         {
-            FromBytesResult<KEY_AMOUNT>(CoordsFromBytesError::INVALID_AMOUNT_OF_BYTES);
+            return CoordsFromBytesResult<KEY_AMOUNT>(CoordsFromBytesError::INVALID_AMOUNT_OF_BYTES);
+        }
+
+        uint8_t checksum = 0;
+        for(uint8_t i = 0; i < (bytes.size() - 1) / 2; ++i)
+        {
+            uint8_t index = i * 2;
+            result.push(KeyCoordinate(bytes[index], bytes[index+1]));
+            checksum += bytes[index] + bytes[index+1];
         }
-        for(uint8_t i = 0; i < bytes.size() / 2; i++)
+
+        if(checksum != bytes[bytes.size() - 1])
         {
-            
+            return CoordsFromBytesResult<KEY_AMOUNT>(CoordsFromBytesError::INVALID_CHECKSUM);
         }
+        
+        return result;
     }
 }
 
diff --git a/unit.cpp b/unit.cpp
index a0dc299..9e231ac 100644
--- a/unit.cpp
+++ b/unit.cpp
@@ -243,9 +243,61 @@ TEST_CASE("Key message decode", "[key transmission]")
 
     auto decoded = decode_coordinates_from_bytes<5>(bytes);
 
+    REQUIRE(decoded.error == CoordsFromBytesError::SUCCESS);
     REQUIRE(decoded.keys.contains(KeyCoordinate(0,0)));
     REQUIRE(decoded.keys.contains(KeyCoordinate(2,0)));
     REQUIRE(decoded.keys.contains(KeyCoordinate(0,2)));
     REQUIRE(decoded.keys.contains(KeyCoordinate(1,1)));
     REQUIRE(decoded.keys.contains(KeyCoordinate(1,2)));
+
+    //Fewer coordinates than the maximum allowed amount
+    bytes.reset();
+    checksum = 2;
+    bytes.push(1);
+    bytes.push(1);
+    bytes.push(checksum);
+
+    decoded = decode_coordinates_from_bytes<5>(bytes);
+
+    REQUIRE(decoded.error == CoordsFromBytesError::SUCCESS);
+    REQUIRE(decoded.keys.contains(KeyCoordinate(1,1)));
+}
+
+TEST_CASE("Malformed message decode", "[key transmission]")
+{
+    {
+        //Invalid checksum
+        uint8_t checksum = 1; //should be 2
+        uint8_t bytes_raw[3] = {1,1, checksum};
+
+        auto bytes = BoundedArray<uint8_t, 3>(bytes_raw);
+        auto decoded = decode_coordinates_from_bytes<1>(bytes);
+
+        REQUIRE(decoded.error == CoordsFromBytesError::INVALID_CHECKSUM);
+
+        //Missing checksum
+        bytes.reset();
+        bytes.push(1);
+        bytes.push(1);
+        decoded = decode_coordinates_from_bytes<1>(bytes);
+        REQUIRE(decoded.error == CoordsFromBytesError::INVALID_AMOUNT_OF_BYTES);
+    }
+}
+
+
+
+TEST_CASE("Key message encode", "[key transmission]")
+{
+    auto original_coordinates = BoundedArray<KeyCoordinate, 3>();
+    original_coordinates.push(KeyCoordinate(3,2));
+    original_coordinates.push(KeyCoordinate(3,2));
+    //Leaving one empty to test that
+    
+    auto decoded = decode_coordinates_from_bytes<3>(coords_to_bytes(original_coordinates));
+
+    REQUIRE(decoded.error == CoordsFromBytesError::SUCCESS);
+    for(int i = 0; i < 2; ++i)
+    {
+        REQUIRE(original_coordinates[i] == decoded.keys[i]);
+    }
 }