The presented circuit is to be controlled, a code-based
electronic locking the operation of the plurality of devices. The circuit uses
a three decimal encoding for the operation of each device. Select so for each
unique device code three-digit numbers 101 to 999. Although this circuit can be
used to control up to 999 devices, for reasons of simplicity, the illustrated
operation of only three units. Additional devices, if necessary, are provided
through connector 10-pin in the circuit connected together. For the operation
of each device is a device-specific method for the operation of the shift lever
is activated by the device code. Code selection: By three push-to-on switches,
conducted each assigned with a specific number the dialed number is displayed
in three 7-segment displays for a short time. When selecting a device counter
and exhibitors will be automatically restored. However the selection device
will be held in engagement by the action of the relay, by means of a pair of
its own contacts. A new selection is accompanied by a short musical note.
Provision for manual reset counters and displays are also included.
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| Fig: 1 |
The circuit consists of a timer 555 (IC1) which is connected
as an astable multivibrator with a duty cycle of 50 percent and a clock period
of a second. The output of IC1 is used as a counter CD4033 decade cum clock
display driver IC (IC2 of IC4) and Johnson-ring against IC CD4017 (IC5 by IC7).
In fact, the clock signal is formed by more IC5 pair wise IC2, IC3 and IC4 IC6,
IC7 plus more, pressing on the switch S1, S2 and S3 respectively routed. The
three groups (each comprising a CD4033, CD4017 and a 7-digit) together
independently with the reset pin 15 of the CD4017 CD4033 and integrated
circuits. Start only with ring-Y0 integrated circuits (CD4017) is high, while
all other outputs (Y1-Y9) are low. At this point, the output of all counters
are also CD4033 account, and therefore the screen 000th.
When the first clock pulse reach to all rev CD2033 CD4017
peer applied to high yield Y0 Y1. At the same time the current number CD4033
peers from zero to one and the corresponding seven-segment displays 1 and Is
moved for the second clock, high performance Y2, count the number of pairs is
increased by one, and CD4033 shows the corresponding second sample The number
can be up to nine clock cycles when Y9 output is high, and the screen displays
the corresponding 9th The clock next (tenth), again theY0 production is high
and the screen is also 0 Then the cycle repeats.
The outputs of the
integrated circuit is CD4017 (IC5 by IC7) connected to inputs of three pins 3
doors N1, N2, N3, and IC8 interior (CD4073). According to the desired code for
each transaction unit, the compounds may be prepared according to the outputs
of the integrated circuit used in the gate CD4017 and to control the operation
of the particular device. For example, if you want the device code are 794, and
then connect the output of IC5 Y7, Y9 IC7 IC6 and Y4 doors and N1. The output
of gate N1 is connected to the number of the control device through a ULN2003
Darlington mass IC (input pin 2 and outputpin15) DPDT RL1 is. When the relay
RL1 energies under the assumption that the switch S5 is turned on, the relay is
latched, since it receives the positive supply voltage with the switch and the
ground via a contact N / O As soon as a device according to the switch is
activated and the appropriate code is chosen properly, it can be done manually
by pressing the appropriate button (S5, S6 and S7) to the OFF position to be
activated.
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| Fig: 2 |
Similar to control other devices, the outputs of gates N2
and N3 connected to the input terminals 3 and 4 ULN2003 relay driver IC, and
output terminals 14 and 13 are connected to the relay RL2 and RL3,
respectively. External free-wheeling diodes are not required by the relay coil,
since they are constructed in the same ULN2003 IC.
The module includes automatic reset. The outputs of the AND
gates are connected. Or wired to claim 1 of the integrated circuit ULN2003 Pins
using diodes D2 to D4 is Thus, when the output of an AND gate goes high, pin
IC9 number too high. Whereby the pin 16 to the low state and RL4 energize which
in turn causes the positive supply, the. With the reset line, which extends to
all counters CI (IC2 by IC7) When the counter is reset, the output of the AND
gate is low and off RL4. Simultaneously, the screen 000 is displayed again,
because the counters are reset. Clear counters and display is not restricted to
the operation of a device with the blocking action of the relay, as explained
above.
Moreover, when the circuit is automatically reset, as
explained above, a musical tone is produced for about five seconds, to indicate
that the device is switched on. As mentioned above, the pin 16 ULN2003 lowered
currently the counter is reset automatically by actuation of the relay RL4. The
transition from the top to the bottom of the pin 16 is configured ULN2003 also
the trigger pin 2 of IC NE555 timer (IC10), which here passed as monostable 5
seconds. The output is connected to the musical tone IC10 IC UM66 (IC11), which
generates a musical tone 5 seconds monostable output pulses.
The code is. Amounts entered via the keys to switch S1, S2
and S3 In cases where an incorrect code is entered, you can back to the correct
code to manually reset circuit by pressing the reset switch S4. With manual
reset, the system will not produce musical note. During recovery, a logic high
level is applied to 15 of the set of counters and counter / controller IC pin
seven segments. Under normal circumstances, these contacts are reset to a logic
low.
The circuit shows the connection of three units; the codes
794, 969 and 337 have respectively. To operate the device before resetting
counter by pressing the button S4, reverse switch S1, so that clock pulses are
applied to the pair of IC2 and IC5, and starts counting. Press S1 DIS1 screens
seven digits. As well as press the S2 and S3 switches for the second and third
position. The other two devices can also function in a similar manner.
To control more devices, just add doors, tables ULN2003
Darlington, relays and switches. Do not forget, all outputs and the door to
connect pin 1 IC9 diodes Automatic reset operation. The inputs of the AND gate
can also be made to the outputs of the integrated circuit CD4017 obtained
terminated with connectors as shown in the diagram of Figure 1. Because these
devices are CMOS high-capacity fan-out are (about 50 pieces), each output can
be connected with a number of gates without degradation of its performance.
Each device is a unique code assigned to 001 to 999 (decimal). To extend the
code, you can do this simply by the assemblies. The IC CD4017, CD4033, and a
seven-segment display Doors must. Same input (or more) as the number of sets /
numbers.
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| Fig: 3 |
The actual size of one side of the printed circuit design
diagram of Figure 1 is shown in Figure 2. Note that not the circuit board
contains C1 and IC9 connected relay/components. They can to the printed
circuit, and the general use, the number of devices that can be controlled by
the user can be mounted. Required items were been made in BERG-STRIP
connections. The arrangement of the components on the printed circuit is shown
in Figure 3.
