The input circuit is composed of LDR, followed by the negative square wave generator circuit around the timer IC (NE555).Here, the bulb is used as a light source to focus the LDR.The characteristic of LDR is that whenever the light focused on LDR is blocked, it triggers and generates a square wave, which is supplied to the counter circuit as an input signal.Therefore, the objects to be counted are arranged in a row and can be moved one by one between the light source and the LDR.
