Some methods for determining small angular deviations have been considered on the example of building objects. The design of an electrostatic cylindrical sensor was put forward, and the use of force action of an electric field was proposed in order to increase the sensitivity of the sensor. The main structural elements of the sensor are a plumb-line weighted at one end and a cylinder surrounding it. The conditions of equilibrium and instability of the position of the plumb arising due to positive feedback in the electric field were considered. An estimated calculation of the time of movement of the plumb until the moment of its touching the inside of the cylinder was made. The calculation result could be taken as a starting point for finding the desired angular deviation. The inaccuracy in the manufacture of the device and the random factors were noted to become influential at small deviations. The paper proposed some ways to solve these problems.