diff --git a/ble_interface.py b/ble_interface.py
new file mode 100644
index 0000000..b58a99e
--- /dev/null
+++ b/ble_interface.py
@@ -0,0 +1,101 @@
+from asyncio import AbstractEventLoop
+import asyncio
+from typing import Dict
+
+from bleak import BleakClient, BleakScanner
+from bleak.backends.characteristic import BleakGATTCharacteristic
+from bleak.backends.service import BleakGATTService
+from bleak.uuids import normalize_uuid_str
+
+import logging
+import struct
+
+import myUUIDs
+
+class ble_interface:
+    CURRENT = "current"
+    VOLTAGE = "volts"
+    CONFIGURATION = "conf"
+    RFRSH_DELAY = "refresh_delay"
+    ON_CONNECT = "on_connect"
+
+    def __init__(self, address, loop: AbstractEventLoop, logger : logging.Logger) -> None:
+        self.address = address
+        self.loop = loop
+        self.client: BleakClient
+        self.log = logger
+        self.callbacks = {}
+        self.services: Dict[str, BleakGATTService] = {}
+        self.handlers = {
+            self.CURRENT: self.__current_meas_handler,
+        }
+
+    async def __connect(self):        
+        device = await BleakScanner.find_device_by_address(self.address, cb=dict(use_bdaddr=False))
+        if device is None:
+            self.log.error("could not find device with address")
+            return
+
+        async with BleakClient(device) as client:
+            self.log.info("Connected")
+            self.client = client
+
+            self.call_callback(self.ON_CONNECT)
+
+            services = client.services.services
+
+            self.parse_services(services)
+
+            await asyncio.Event().wait()
+
+    def parse_services(self, services: Dict[int, BleakGATTService]):
+        for i in services:
+            s = services[i]
+            if(s.uuid == normalize_uuid_str(myUUIDs.METROLOGY_SERVICE)):
+                if(s.characteristics[0].uuid == normalize_uuid_str(myUUIDs.ELECTRIC_CURRENT_CHAR)):
+                    self.services[self.CURRENT] = s
+
+                if(s.characteristics[0].uuid == normalize_uuid_str(myUUIDs.VOLTAGE_CHAR)):
+                    self.services[self.VOLTAGE] = s
+
+            
+            if(s.uuid == normalize_uuid_str(myUUIDs.CONFIGURATION_SERVICE)):
+                self.services[self.CONFIGURATION] = s
+    
+    def connect(self):
+        self.log.info("connecting")
+
+        self.loop.create_task(self.__connect())
+
+    def subscribe_to(self, to: str):
+        self.loop.create_task(self.__subscribe_to(to))
+ 
+    async def __subscribe_to(self, to: str):
+        self.log.info("subscribing to %s", to)
+        for c in self.services[to].characteristics:
+            await self.client.start_notify(c, self.handlers[to])
+    
+    def add_callback(self, id: str, callback):
+        if(not id in self.callbacks):
+            self.callbacks[id] = []
+        self.callbacks[id].append(callback)
+
+    def call_callback(self, id: str, *params):
+        if(id in self.callbacks):
+            for c in self.callbacks[id]:
+                if(params):
+                    c(self, *params)
+                else:
+                    c(self)
+    
+    def __current_meas_handler(self, char: BleakGATTCharacteristic, data: bytearray):
+        val = struct.unpack("<I", data)[0]
+        handle = next(i for i,c in enumerate(self.services[self.CURRENT].characteristics) if c.handle == char.handle)
+
+        self.call_callback(self.CURRENT, handle, val)
+        if(self.CURRENT in self.callbacks):
+            for c in self.callbacks[self.CURRENT]:
+                c(self, handle, val)
+
+    def update_refresh_delay(self, val: int):
+        pass
\ No newline at end of file
diff --git a/main.py b/main.py
index 45112a2..3d941cf 100644
--- a/main.py
+++ b/main.py
@@ -8,21 +8,27 @@ import time
 from bleak import BleakClient, BleakScanner
 from bleak.backends.characteristic import BleakGATTCharacteristic
 from bleak.uuids import normalize_uuid_str
+from ble_interface import ble_interface
 
 import dearpygui.dearpygui as dpg
 
 import myUUIDs
+from ble_interface import ble_interface
 
 logger = logging.getLogger(__name__)
 
-loop = None
+loop: asyncio.AbstractEventLoop
+device: ble_interface
 
 current_meas = {}
 start_time = None
 
-def current_meas_handler(characteristic: BleakGATTCharacteristic, data: bytearray):
-    value = struct.unpack("<I", data)[0]
-    handle = characteristic.handle
+def on_connect_handler(device: ble_interface):
+    device.subscribe_to(device.CURRENT)
+
+def current_meas_handler(device: ble_interface, input_handle: int, newval: int):
+    value = newval
+    handle = input_handle
     logger.info("%s: %f", handle, value * 1.0e-6)
 
     global start_time
@@ -41,37 +47,13 @@ def current_meas_handler(characteristic: BleakGATTCharacteristic, data: bytearra
     current_meas[handle].append(((time.monotonic_ns() - start_time) * 1e-9, value * 1e-6))
 
     dpg.set_value(f"serie{handle}", [ [v[0] for v in current_meas[handle]], [v[1] for v in current_meas[handle]] ])
-    dpg.fit_axis_data("x_axis")
-    dpg.fit_axis_data("y_axis")
+    # dpg.fit_axis_data("x_axis")
+    # dpg.fit_axis_data("y_axis")
 
 
-async def connect():
-    logger.info("starting scan...")
-
-    device = await BleakScanner.find_device_by_address("84:F7:03:1B:C6:A2", cb=dict(use_bdaddr=False))
-    if device is None:
-        logger.error("could not find device with address")
-        return
-
-    logger.info("connecting to device...")
-
-    async with BleakClient(device) as client:
-        logger.info("Connected")
-
-        current_svc_handle = 0
-        services = client.services.services
-        metrology_svcs = [services[i] for i in services if services[i].uuid == normalize_uuid_str(myUUIDs.METROLOGY_SERVICE)]
-
-        current_meas_svc = next(s for s in metrology_svcs if s.get_characteristic(myUUIDs.ELECTRIC_CURRENT_CHAR))
-
-        for c in current_meas_svc.characteristics:
-            await client.start_notify(c, current_meas_handler)
-        
-        await asyncio.Event().wait()
-        # await client.stop_notify(args.characteristic)
-
-def start_connection():
-    loop.create_task(connect())
+def update_refresh_rate(sender, app_data):
+    logger.info("refresh rate %d", app_data)
+    device.update_refresh_delay(app_data)
 
 async def init_gui():
     dpg.create_context()
@@ -79,9 +61,10 @@ async def init_gui():
     dpg.setup_dearpygui()
 
     with dpg.window(label="Controls", pos = [0, 0], width = dpg.get_viewport_width(), height = 100):
-        dpg.add_button(label="Connect", callback=start_connection)
+        dpg.add_button(label="Connect", callback=device.connect)
+        dpg.add_input_int(label="Refresh Delay", callback=update_refresh_rate, on_enter=True, tag="refresh delay")
         
-    with dpg.window(label="Graphs", pos = [0, 100]):
+    with dpg.window(label="Graphs", pos = [0, 100], width = dpg.get_viewport_width(), height = 500):
         with dpg.plot(label="Current", width = -1, height = -1):
             dpg.add_plot_legend()
 
@@ -102,7 +85,13 @@ if __name__ == "__main__":
         level="INFO",
         format="%(asctime)-15s %(name)-8s %(levelname)s: %(message)s",
     )
+
     
     loop = asyncio.get_event_loop()
+    
+    device = ble_interface("84:F7:03:1B:C6:A2", loop, logger)
+    device.add_callback(device.ON_CONNECT, on_connect_handler)
+    device.add_callback(device.CURRENT, current_meas_handler)
+    
     loop.create_task(init_gui())
     loop.run_forever()