fixed y_offset substraction

raspberry-pi/sensors.py

@@ -135,7 +135,7 @@ class AcusticSensor:
       distance_left = val1 * self.sonic_speed
       distance_right = val2 * self.sonic_speed
       x = (self.sensor_distance**2 - distance_right**2 + distance_left**2) / (2*self.sensor_distance) + self.left_sensor_x_offset
-      y = math.sqrt(max(distance_left**2 - x**2, 0)) + self.sensor_y_offset
+      y = math.sqrt(max(distance_left**2 - x**2, 0)) - self.sensor_y_offset
       return(x,y)
     except Exception as e:
       print(values)