 				bMeasuring = false;
 				iMeasureCount ++;
 				break;
+			case 'z':	// ZERO MOTOR
+				zeroMotor();
+				break;
 		}
 	}
 	

	if ((millis() - shutdownTimeout) > 250)
	{
		// If we have not already shut the motor down.
		if (bAllowMotorShutdown)
		{
			motor.shutdown();
			bAllowMotorShutdown = false;
		}
	}
	
	

			// And reset the screen time.
			iOnScreenTime = 0;
			#ifdef HEIGHT_DEBUG
			Serial.print("[HM] too large delta between LDRs ");
			Serial.println(iDelta);
			#endif
		}
		
		#ifdef HEIGHT_DEBUG // csv: on screen, ldr1, ldr2, min, max, value
		Serial.print(bOnScreen ? 100 : 0); Serial.print(",");	
		Serial.print(iSample1); Serial.print(",");
		Serial.print(iSample2); Serial.print(",");
		
		Serial.print(min); Serial.print(",");
		Serial.print(max); Serial.print(",");
		Serial.print(iMean); Serial.print("\n");
