diff --git a/main.py b/main.py
index bef42ec..25ceca2 100644
--- a/main.py
+++ b/main.py
@@ -1,8 +1,29 @@
 from machine import Pin, SPI, SoftI2C
 import framebuf
+import json
+import machine
+import network
+import ubinascii
+import utime
+
+from umqtt.simple import MQTTClient
+
 import ssd1306
 import mcp4
 
+VOLUME_MAX = 128
+
+MQTT_KEEPALIVE = 60
+MQTT_UPDATE_INTERVAL = 60
+
+
+state = {
+    "volume": {
+        "left": 0,
+        "right": 0,
+    }
+}
+last_update = 0
 
 i2c = SoftI2C(sda=Pin(2), scl=Pin(16))
 oled_width = 128
@@ -11,19 +32,149 @@ oled = ssd1306.SSD1306_I2C(oled_width, oled_height, i2c)
 buf = bytearray((oled_height // 8) * oled_width)
 fbuf = framebuf.FrameBuffer1(buf, oled_width, oled_height)
 
+sta_if = network.WLAN(network.STA_IF)
 
 spi = SPI(1)
 cs = Pin(15, mode=Pin.OUT, value=1)
 pot = mcp4.MCP4(spi, cs)
 
+with open("settings.json", "r") as f:
+    settings = json.load(f)
 
-def update():
+mqtt = None
+mqtt_client_id = ubinascii.hexlify(machine.unique_id())
+mqtt_broker = settings["mqtt"]["broker"]
+mqtt_prefix = settings["mqtt"]["prefix"]
+
+
+def on_message(topic, msg):
+    print((topic, msg))
+    try:
+        msg = json.loads(msg)
+    except:
+        return
+    if volume := msg.get("volume"):
+        if isinstance(volume.get("left"), int):
+            pot.write(0, volume["left"])
+        if isinstance(volume.get("right"), int):
+            pot.write(1, volume["right"])
+
+
+def loop():
+    global mqtt, state, last_update
+
+    state_changed = False
     PW0 = pot.read(0)
     PW1 = pot.read(1)
+
+    if PW0 != state["volume"]["left"]:
+        state["volume"]["left"] = PW0
+        state_changed = True
+    if PW1 != state["volume"]["right"]:
+        state["volume"]["right"] = PW1
+        state_changed = True
+
+    if not sta_if.active():
+        sta_if.active(True)
+        sta_if.connect(settings["wifi"]["ssid"], settings["wifi"]["password"])
+
+    network_status = "OFF"
+    if sta_if.active():
+        network_status = "ACT"
+    if sta_if.isconnected():
+        network_status = "OK"
+        if not mqtt:
+            mqtt = MQTTClient(mqtt_client_id, mqtt_broker, keepalive=MQTT_KEEPALIVE)
+            mqtt.set_callback(on_message)
+            mqtt.connect()
+            mqtt.subscribe(f"{mqtt_prefix}/set")
+            mqtt_device = {
+                "identifiers": mqtt_client_id,
+                "manufacturer": "correl",
+                "model": "digital-audio-switch",
+                "name": "Digital Audio Switch",
+            }
+
+            mqtt.publish(
+                f"homeassistant/number/digital-audio-switch/volume-left/config".encode(),
+                json.dumps(
+                    {
+                        "name": "Digital Audio Switch Volume (Left)",
+                        "command_topic": f"{mqtt_prefix}/set",
+                        "command_template": '{"volume": {"left": {{value}}}}',
+                        "state_topic": f"{mqtt_prefix}/state",
+                        "value_template": "{{ value_json.volume.left }}",
+                        "availability_topic": f"{mqtt_prefix}/status",
+                        "min": 0,
+                        "max": VOLUME_MAX,
+                        "mode": "slider",
+                        "step": 1,
+                        "unique_id": "digital-audio-switch-volume-left",
+                        "device": mqtt_device,
+                    }
+                ).encode(),
+                retain=True,
+            )
+            mqtt.publish(
+                f"homeassistant/number/digital-audio-switch/volume-right/config".encode(),
+                json.dumps(
+                    {
+                        "name": "Digital Audio Switch Volume (Right)",
+                        "command_topic": f"{mqtt_prefix}/set",
+                        "command_template": '{"volume": {"right": {{value}}}}',
+                        "state_topic": f"{mqtt_prefix}/state",
+                        "value_template": "{{ value_json.volume.right }}",
+                        "availability_topic": f"{mqtt_prefix}/status",
+                        "min": 0,
+                        "max": VOLUME_MAX,
+                        "mode": "slider",
+                        "step": 1,
+                        "unique_id": "digital-audio-switch-volume-right",
+                        "device": mqtt_device,
+                    }
+                ).encode(),
+                retain=True,
+            )
+            mqtt.publish(
+                f"homeassistant/number/digital-audio-switch/volume-master/config".encode(),
+                json.dumps(
+                    {
+                        "name": "Digital Audio Switch Volume (Master)",
+                        "command_topic": f"{mqtt_prefix}/set",
+                        "command_template": '{"volume": {"right": {{value}}, "left": {{value}}}}',
+                        "state_topic": f"{mqtt_prefix}/state",
+                        "value_template": """
+                            {%set values = value_json.volume.left,
+                                           value_json.volume.right %}
+                            {{ values|max }}
+                        """,
+                        "availability_topic": f"{mqtt_prefix}/status",
+                        "min": 0,
+                        "max": VOLUME_MAX,
+                        "mode": "slider",
+                        "step": 1,
+                        "unique_id": "digital-audio-switch-volume-master",
+                        "device": mqtt_device,
+                    }
+                ).encode(),
+                retain=True,
+            )
+
+        if state_changed or utime.time() - last_update >= MQTT_UPDATE_INTERVAL:
+            mqtt.publish(f"{mqtt_prefix}/status".encode(), b"online", retain=True)
+            mqtt.publish(
+                f"{mqtt_prefix}/state".encode(), json.dumps(state).encode(), retain=True
+            )
+
+            last_update = utime.time()
+        mqtt.check_msg()
     oled.fill(0)
     oled.text(f"PW0: {PW0}", 0, 0)
     oled.text(f"PW1: {PW1}", 0, 10)
+    oled.text(f"NET: {network_status}", 65, 0)
     oled.show()
 
 
-update()
+while True:
+    loop()
+    utime.sleep(1)