In the earlier post we mastered a basic barcode sensor circuit, here we are going to research precisely how the felt pulses could be changed for obtaining unique sets of high low outputs from the IC 4033 as a reaction to several barcodes designs. This excellent outputs may be then useful for triggering a lock or an alarm.
The concept is dependent on the truth that the lines of the bar code have various thicknesses which in turn might be scanned to deliver unique time intervals across the whole bar code design.
In the figure below we observe the circuit design for producing unique 7 segment outputs as a reaction to the opamp sensor feed.
In the design, a 4033 IC that could be a 7 segment decoder is utilized with a IC 555 clock generator for producing the unique results in a reaction to the barcode.
Pin4 of the IC 555 is associated with the opamp sensor output signifying that the IC 555 is going to be active and run the IC 4033 only for the white spaces on the barcode, since the white spaces are meant to produce high logic pulses across the opamp output could keep the IC 555 pin4 reset pin started throughout these types of periods.
And while the IC 555 is clocking, IC 4033 could be busy producing the BCD sequences across its output pins, and across the black lines of the barcode this series generation will remain inhibited.
Now to be able to get a consistent and constant outputs from the IC 4033 for individual barcode, the barcode card must be swiped making use of a motor mechanism or a solenoid mechanism with a controlled continuous speed instead of with hand.
The motor might be controlled with a set/reset mechanism such that it moves the whole barcode length before the laser/LDR assembly.
The motor switch ON might initiate the opamp circuit which then begins sensing the barcode pulses to modify it into a PWM type.
This PWM is immediately replied by the IC 555/4033 circuit until the complete barcode is study.
The moment the reading finishes the outputs of the 4033 remain latched with a unique set of high and low outputs.
These outputs could be separately set up with relay mechanisms with the intention to switch on an electrical lock, a gate, or any meant security method.
A 4 input NAND gate IC 4012 could be utilized and designed with any specific four picked unique outputs of the decoder for signaling a security relay.
If 3 high outputs are picked then one of the NAND inputs could possibly be shorted to the positive supply.
