Touchless system for Door Open And Close Automatically

Door Open And Close Automatically.

Touchless system for Door Open And Close Automatically With Time Delay, by using obstacle sensor whish gives output high 1 . example IR SENSOR. Idea application from NE555 (Five five timer) Mono-stable Operation .

Touchless system for Door Open And Close Automatically.

Mono-stable Operation 

For mono-stable operation, any of these timers can be connected . If the output is low, application of a negative-going pulse to the trigger (TRIG) sets the flip-flop (Q goes low), drives the output high, and turns off Q. Capacitor C then is charged through RA until the voltage across the capacitor reaches the threshold voltage of the threshold (THRES) input. If TRIG has returned to a high level, the output of the threshold comparator resets the flip-flop (Q goes high), drives the output low, and discharges C through Q.

Monostable operation is initiated when TRIG voltage falls below the trigger threshold. Once initiated, the sequence ends only if TRIG is high for at least 10 µs before the end of the timing interval. When the trigger is grounded, the comparator storage time can be as long as 10 µs, which limits the minimum monostable pulse width to 10 µs. Because of the threshold level and saturation voltage of Q1, the output pulse duration is approximately tw = 1.1RC. Is a plot of the time constant for various values of R= 470K and C3, C7, C5 = 2.2u. The threshold levels and charge rates both are directly proportional to the supply voltage, VCC. The timing interval is, therefore, independent of the supply voltage, so long as the supply voltage is constant during the time interval. Applying a negative-going trigger pulse simultaneously to RESET and TRIG during the timing interval discharges C and reinitiates the cycle, commencing on the positive edge of the reset pulse. The output is held low as long as the reset pulse is low. To prevent false triggering, when RESET is not used, it should be connected to VCC.

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