diff --git a/README.md b/README.md
index ce61d6c..b252c74 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,6 @@
+[![Build Status](https://travis-ci.org/Nikolay-Kha/PyCNC.svg?branch=master)](https://travis-ci.org/Nikolay-Kha/PyCNC)
+
+# PyCNC
 This project bring CNC control for Raspberry Pi or any ARM based Linux boards.
 Typically there is no way to control stepper motors from Linux runtime
 environment due to the lack of real time GPIO control. Even kernel based
diff --git a/cnc/hal_raspberry/hal.py b/cnc/hal_raspberry/hal.py
index 3a8ef95..8946ce0 100644
--- a/cnc/hal_raspberry/hal.py
+++ b/cnc/hal_raspberry/hal.py
@@ -51,25 +51,41 @@ def init():
     pins = STEP_PIN_MASK_X | STEP_PIN_MASK_Y | STEP_PIN_MASK_Z
     dma.clear()
     dma.add_pulse(pins, STEPPER_PULSE_LINGTH_US)
-    while True:
-        if (STEP_PIN_MASK_X & pins) != 0 and gpio.read(ENDSTOP_PIN_X) == 0:
-            pins &= ~STEP_PIN_MASK_X
-            dma.clear()
-            dma.add_pulse(pins, STEPPER_PULSE_LINGTH_US)
-        if (STEP_PIN_MASK_Y & pins) != 0 and gpio.read(ENDSTOP_PIN_Y) == 0:
-            pins &= ~STEP_PIN_MASK_Y
-            dma.clear()
-            dma.add_pulse(pins, STEPPER_PULSE_LINGTH_US)
-        if (STEP_PIN_MASK_Z & pins) != 0 and gpio.read(ENDSTOP_PIN_Z) == 0:
-            pins &= ~STEP_PIN_MASK_Z
-            dma.clear()
-            dma.add_pulse(pins, STEPPER_PULSE_LINGTH_US)
-        if pins == 0:
-            break
-        dma.run(False)
-        # limit velocity at ~10% of top velocity
-        time.sleep((1 / 0.10) / (STEPPER_MAX_VELOCITY_MM_PER_MIN
-                                 / 60 * STEPPER_PULSES_PER_MM))
+    st = time.time()
+    max_pulses_left = int(1.2 * STEPPER_PULSES_PER_MM * max(
+                      TABLE_SIZE_X_MM, TABLE_SIZE_Y_MM, TABLE_SIZE_Z_MM))
+    try:
+        while max_pulses_left > 0:
+            if (STEP_PIN_MASK_X & pins) != 0 and gpio.read(ENDSTOP_PIN_X) == 0:
+                pins &= ~STEP_PIN_MASK_X
+                dma.clear()
+                dma.add_pulse(pins, STEPPER_PULSE_LINGTH_US)
+            if (STEP_PIN_MASK_Y & pins) != 0 and gpio.read(ENDSTOP_PIN_Y) == 0:
+                pins &= ~STEP_PIN_MASK_Y
+                dma.clear()
+                dma.add_pulse(pins, STEPPER_PULSE_LINGTH_US)
+            if (STEP_PIN_MASK_Z & pins) != 0 and gpio.read(ENDSTOP_PIN_Z) == 0:
+                pins &= ~STEP_PIN_MASK_Z
+                dma.clear()
+                dma.add_pulse(pins, STEPPER_PULSE_LINGTH_US)
+            if pins == 0:
+                break
+            dma.run(False)
+            # limit velocity at ~10% of top velocity
+            time.sleep((1 / 0.10) / (STEPPER_MAX_VELOCITY_MM_PER_MIN
+                                     / 60 * STEPPER_PULSES_PER_MM))
+            max_pulses_left -= 1
+            if st is not None:
+                if time.time() - st > 2:
+                    logging.critical("Calibration still in progress. Check if "
+                                     "machine is moving.\nPress Ctrl+C to "
+                                     "cancel calibration and proceed as is.")
+                    st = None
+        if pins != 0:
+            logging.critical("Calibration has failed. You may proceed, but be "
+                             "careful.")
+    except KeyboardInterrupt:
+        logging.critical("Calibration has canceled by user. Be careful.")
 
 
 def spindle_control(percent):