Single-cylinder telescopic boom length sensing device

The invention belongs to the technical field of length sensing, and provides a single-cylinder telescopic boom length sensing device. A fixing frame is mounted on a boom head of a base boom through amounting frame. A pressing part is connected between the fixing frame and the mounting frame. A rolling wheel which is rolling connection with a movable arm is connected with the fixing frame. The fixing frame comprises a shaft seat. A pressing part is connected with one end of the shaft seat. A fixing plate is arranged at the other end of the shaft seat. The rolling wheel comprises a wheel axle and a wheel body. The wheel body is in key connection with the wheel axle. One end of the wheel axle is rotationally connected to the fixing plate. The other end of the wheel axle is rotationally connected to an L-shaped plate. The L-shaped plate is provided with a fixing mechanism matched with the wheel axle. An encoder matched with the wheel axle is arranged on the fixing plate. The rolling wheelis in rolling connection