Self-detecting digital-quantity acquisition device

The invention discloses a self-detecting digital-quantity acquisition device which includes a microprocessor, a USB interface power supplying circuit, a digital-quantity input interface and a self-detecting circuit. The digital-quantity input interface is connected to the microprocessor through a filtering circuit and a buffer circuit sequentially. The USB interface power supplying circuit includes a USB conversion module. One end of the USB conversion module is connected to the microprocessor and the other end is connected to a USB port at the outer end. An input end of the self-detecting circuit is connected to the microprocessor and an output end is connected to the digital-quantity input interface through a unidirectional switch-on circuit. The beneficial effects of the self-detecting digital-quantity acquisition device are that a USB power supplying mode is adopted and a system is provided with power through a USB conversion chip so that the device obtains a power supply only when inserted into a main-co