diff --git a/measure.py b/measure.py
index ca6b8667551b4a9738b1b0085c6ad59cbc52439f..777afa36fd3d2bee01bfa57ee5785813bb3814bf 100644
--- a/measure.py
+++ b/measure.py
@@ -66,8 +66,8 @@ class OhmPiHardware:
                 lap = datetime.datetime.utcnow()
                 _readings.append([elapsed_seconds(start_time), self.tx.current, self.rx.voltage])
                 sleep_time = sampling_rate/1000.-elapsed_seconds(lap)
-                print(f'sleep_time')
-                time.sleep(np.min[sleep_time, np.abs(sleep_time)])
+                print(f'sleep_time: {sleep_time}')
+                time.sleep(np.min([sleep_time, np.abs(sleep_time)]))
             data = np.array(_readings)
 
         if sampling_rate is None: