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4-Bit Electronic Clock DIY Kit
1. Introduction
YSZ-4 four electronic clock, it takes AT89C2051 as its core, a total of 16 electronic
components to come true the two channels of the alarm clock, (8:00-20:00) on time
alarm ,accurate adjustment , and other functions.
2. Parameter
NO. Parameter Value
1 Operating voltage DC 3V-6V
2 PCB board material RF-4
3 Size 52mm*42mm
3. Principle
The whole system by MCU minimum system, key input circuit, display circuit,
buzzer circuit and power supply parts.
1>. MCU minimum system: including the U1 (AT89C2051), C1, R1 for power on
reset circuit .Clock circuit is composed of C2， C3 and Y1.
2>. The pressed key input circuit：composed of S1, S2, short press the button
once a loud buzzer rang, long press the button once two loud buzzer rang.
3>. The display circuit：4bits common cathode and on PR1 Resisters Packs .
4>. Buzzer circuit：composed of Q1, R2 and LS1, short press the button once a
loud buzzer rang, long press the button once two loud buzzer rang.
5>. J1 is 5v power supply input terminal, C4 filtering.
4. Operation instruction
It will display 12:59 when Power-on，while is normal interface("hours:minutes").
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The both channels of alarm clock are opened.At the same time,the first alarm clock
has been set at 13:01.the second alarm clock has been set at 13:02.
After power on ,short press S2.The display of digital tube will switch between
"hours:minutes" and "minutes:seconds";Long press S1 to enter the system Settings
menu. there are A, B, C, D, E, F, G, H, I submenu. Short press S1 sub-menu plus
increase by degrees。finally back to the normal interface
A Sub menu : Correction for hours
Display data will add 1 after press S2.after adjusted the A Submenu,then short
press S2 to save the adjusted results and quit A submenu,enter B sbumenu
B Sub menu : Correction for minutes
Display data will add 1 after press S2.after adjusted the B Submenu,then short
press S2 to save the adjusted results and quit B submenu,enter C sbumenu
C Sub menu:on time alarm switch
The default state is ON (on-time-alarm is open from 8:00 to 20:00)
It will switch between ON and OFF(on-time-alarm is closed) when press S2.
Short press S2 to save the adjusted results and quit C submenu,enterD sbumenu
D Sub menu:The first alarm-clock switch
The default state is ON (the first alarm-clock is opened)
It will switch between ON and OFF(first-alarm-clock is closed) when press S2。
If set to ON, short press S1 to save and quit,then enter E submenu;
If set to OFF, short press S1 to save and quit ,then enter G submenu;
E Sub menu:The first alarm clock set for hours
Display data will add 1 after press S2.after adjusted the E Submenu,then short
press S2 to save the adjusted results and quit E submenu,enter F sbumenu
F Sub menu:The first alarm clock set for minutes
Display data will add 1 after press S2.after adjusted the F Submenu,then short
press S2 to save the adjusted results and quit F submenu,enter G sbumenu
G Sub menu:The Second alarm-clock switch
The default state is ON (the second alarm-clock is opened)
It will switch between ON and OFF(second-alarm-clock is closed) when press
S2。
If set to ON, short press S1 to save and quit ，then enter H submenu;
If set to OFF, short press S1 to save and quit ，then enter normal interface;
H Sub menu:The second alarm clock set for hours
Display data will add 1 after press S2.after adjusted the F Submenu,then short
press S2 to save the adjusted results and quit H submenu,enter I sbumenu
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I Sub menu:The second alarm clock set for hours
Display data will add 1 after press S2.after adjusted the I Submenu,then short
press S2 to save the adjusted results and quit H submenu, then enter normal interface.
Second correction:
Short press S2 in the normal interface,then enter "minutes : seconds"
interface .Long press S2,make the second zero.Then short press S2 twice enter normal
interface
5. Schematic
Note: there is direction for PR1 Resisters Packs , there is one side of the word in
the direction of the MCU.Pay an attention!!!
6. Component listing
NO. Component Name PCB Marker Parameter QTY
1 Metal Film Resistor R1,R2 10K 2
2 Ceramic Capacitor C2,C3 30pf 2
3 Ceramic Capacitor C4 0.1uf 104 1
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4 Electrolytic Capacitor C1 10uF/25V 1
5 Network Resistor PR1 1K 1
6 Crystal Oscillator Y1 12MHz 1
7 S8550 Q1 TO-92 1
8 Button S1,S2 6*6*5mm 2
9 AT89C2051 U1 DIP-20 1
10 IC Socket U1 DIP-20 1
11 Active Buzzer LS1 5V 1
12 Digital Tube DS1 4Bit Red 1
13 DC Socket J1 3.5mm 1
14 Power Cable USB to 3.5mm 1
NOTE:Users can complete the installation by PCB silk screen and
component listing
7. Installation Steps
Step 1:Install 2pcs Resistor,3pcs ceramic capacitor,1pcs Crystal Oscillator
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Step 2:Install 1pcs Network Resistor.Pay attention to the installation
direction.
Step 3:Install IC Socket.But pay attention to the installation direction.
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Step 4: Install 2pcs button.But pay attention to the installation
direction.Install 1pcs S8850.
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Step 5: Install 1pcs Power socket;1pcs Electrolytic Capacitor;1pcs
Buzzer.
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Step 6: Install 4Bit Digital Tube and IC.And then test!
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8.Effect demonstration(Only for appreciation)
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