Some fixes.

config.json

@@ -86,7 +86,7 @@
     "frequency": 25000
   },
   "activated-channels": [ 0, 1],
-  "interval": 1.0,
+  "interval": 1,
   "use_difference": false,
   "thresholds-for": "inside",
   "thresholds": {

src/lowlevel.py

@@ -49,7 +49,7 @@ class LowLevel(metaclass=Singleton):
         lchbits = channel & 0x03                         
         to_send = [hchbit | 0x06, lchbits << 6, 0x00]
         self.__activate()
-        r=self.__spi.xfer(to_send)
+        r = self.__spi.xfer(to_send)
         self.__deactivate()
         GPIO.output(pin, False)    
         highbyte = r[1]                                  

src/service.py

@@ -15,11 +15,19 @@ class Service(object):
     def run(self):
         interval = self.__cfg.get_data()["interval"]
         t = time.time()
+        last = None
+        ran = False
         while True:
             t = time.time()
-            time.sleep(t + interval - time.time())
-            thread = Thread(self.work)
-            thread.start()
+            if int(t) % interval == 0 and not ran:
+                thread = Thread(self.work)
+                thread.start()
+                ran = True
+                last = int(t)
+            else:
+                time.sleep(0.01)
+                if t > last:
+                    ran = False
         pass
 
     def work(self):