Abstract: An apparatus and method for measuring the horizontal position uses a gas bubble in a bubble level. The gas bubble is in a cylindrical sealed housing that is partially filled with liquid. At least two light-emitting devices are used to illuminate the gas bubble and an inner bottom surface of the bubble level. A corresponding number of receiving devices are used to receive the light that is either reflected by the inner bottom surface or is reflected and refracted by the gas bubble. The amount of light received is translated into an electrical signal and is sent to a processing unit to calculate the position of the gas bubble. The light-emitting devices and the receiving devices are disposed in an alternating manner at the periphery of the cylindrical sealed housing.

Abstract: An apparatus and method for measuring the horizontal position uses a gas bubble in a bubble level. The gas bubble is in a cylindrical sealed housing that is partially filled with liquid. At least two light-emitting devices are used to illuminate the gas bubble and an inner bottom surface of the bubble level. A corresponding number of receiving devices are used to receive the light that is either reflected by the inner bottom surface or is reflected and refracted by the gas bubble. The amount of light received is translated into an electrical signal and is sent to a processing unit to calculate the position of the gas bubble. The light-emitting devices and the receiving devices are disposed in an alternating manner at the periphery of the cylindrical sealed housing.