Gecko CLK036 Supplement

GEKCO Inc.
1565 SW Cypress Ln
McMinnville, OR 97128
[phone] P/N 595-324 REV 1.0
Copyright 2018
GEKCO Inc.
All Rights Reserved
Printed in the United States of America
c
GEKCO
DIGITAL CLOCK
MODEL CLK036
ASSEMBLY & OPERATION MANUAL

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GEKCO DIGITAL CLOCK P/N CLK036 ASSEMBLY & OPERATION MANUAL
GEKCO INC. Rev 1.0 1
TABLE OF CONTENTS
1. INTRODUCTION................................................................................................................................................ 3
2. OPERATIONAL SUMMARY.......................................................................................................................... 3
3. PARTS AND UNPACKING.............................................................................................................................. 4
3.1. TOP LEVELPARTS LIST ...................................................................................................................................... 4
3.2. DISPLAY BOARD PARTS LIST.............................................................................................................................. 5
3.3. MAIN BOARD PARTS LIST................................................................................................................................... 5
3.4. FINALASSEMBLY HARDWARE PARTS LIST....................................................................................................... 7
3.5. ENCLOSURE PARTS LIST..................................................................................................................................... 8
4. ASSEMBLY NOTES........................................................................................................................................... 9
4.1. TOOLS............................................................................................................................................................... 9
4.2. ASSEMBLY ...................................................................................................................................................... 9
4.3. SOLDERING..................................................................................................................................................... 9
5. STEP-BY-STEP ASSEMBLY .........................................................................................................................10
5.1. MAIN CIRCUITBOARD...................................................................................................................................... 10
6. INITIAL TESTS.................................................................................................................................................12
7. FINAL TESTS....................................................................................................................................................13
8. IN CASE OF DIFFICULTY ............................................................................................................................13
9. FINAL PCA ASSEMBLY................................................................................................................................13
10. FINAL ASSEMBLY......................................................................................................................................13
11. THEORY OF OPERATION.......................................................................................................................16
11.1. BLOCKDIAGRAM.............................................................................................................................................. 16
11.1. MAIN BOARD CIRCUIT DESCRIPTION............................................................................................................... 16
11.2. DISPLAY BOARD CIRCUITDESCRIPTION..........................................................................................................17
12. FIRMWARE ..................................................................................................................................................18
12.1. FLOWCHART ....................................................................................................................................................18
12.2. FIRMWARE DESIGN DESCRIPTION....................................................................................................................19
13. PCA PICTORIAL DIAGRAMS.................................................................................................................19
13.1. MAIN BOARD....................................................................................................................................................19
13.2. DISPLAY BOARD ...............................................................................................................................................20
14. SCHEMATIC MAIN BOARD....................................................................................................................22
15. SCHEMATIC DISPLAY BOARD............................................................................................................. 23
16. DOCUMENT REVISION HISTORY........................................................................................................ 24

GEKCO DIGITAL CLOCK P/N CLK036 ASSEMBLY & OPERATION MANUAL
2 REV 1.0 GEKCO INC.
LIST OF FIGURES
FIGURE 1:MAIN BOARD COMPLETED ASSEMBLY...............................................................................................10
FIGURE 2MAIN BOARD TOP VIEW1.................................................................................................................... 10
FIGURE 3:MAIN BOARD TOP VIEW2...................................................................................................................10
FIGURE 4:MAIN BOARD TOP VIEW3...................................................................................................................10
FIGURE 5:MAIN BOARD TOP VIEW4...................................................................................................................11
FIGURE 6:MAIN BOARD WITH STANDOFFS...........................................................................................................11
FIGURE 7:MAIN AND DISPLAY BOARD INTERFACE CONNECTOR MOUNTING.....................................................12
FIGURE 8RTCMODULE ASSEMBLY.................................................................................................................... 13
FIGURE 9ENCLOSURE BACK ................................................................................................................................14
FIGURE 10ENCLOSURE BACK WITH TOP .............................................................................................................14
FIGURE 11DISPLAY BOARD TOP SIDE .................................................................................................................20
FIGURE 12DISPLAY BOARD BOTTOM SIDE..........................................................................................................21

CLK036
GEKCO INC. Rev 1.0 3
1. Introduction
The Digital Clock Model CLK056 was designed to fill the need for an accurate digital clock with the
capabilities of two time zone displays in a compact format.
This clock has 6 digits for hours, minutes and seconds and the hours displaycan alternate between
two time zones, i.e. Coordinated Universal Time (UTC) and local time.
The CLK056 is offered in kit form or fullyassembled and tested. The kit is veryeasy to assemble with
no surface mount parts.
This step bystep manualwill guide you through the process to complete the assembly and testing of
the model CLK056 Digital Clock. The manual was designed so a totalbeginner in electronics can be
successful but the more experienced builder can skip any unnecessaryinformation. Also this design is
fullyopen source for both the hardware and firmware. There are full schematics and pictorial diagrams
of the hardware, also there are links and flowcharts of the firmware microcontroller code.
2. Operational Summary
The Model CLK036 has 8 digits of seven segment displays to displaytime zone one HOURS (UTC),
time zone 2 HOURS (local), MINUTES and SECONDS.
The eight digit displayprovides two time zones Hours, Hours, Minutes and Seconds
The displayLEDs are high contrast red, 0.36 inch character height
Adjustable displaybrightness
Local hours can be set for 12 or 24 hour mode
Veryaccurate Real Time Clock (RTC) with batterybackup
Powered by a U.L. listed 5 VDC walladapter
Size: 4.16 x 2.35 x 1.46 inches (Width x Heightx Depth)
Weight: 0.30 pounds

GEKCO DIGITAL CLOCK P/N CLK036 ASSEMBLY & OPERATION MANUAL
4 REV 1.0 GEKCO INC.
3. Parts and Unpacking
The kit is packaged in the order that the assemblyis recommended. Each assembly block has it’s
associated parts bag. Onlyopen a parts bag when called for during assemblyto avoid misplacing parts.
3.1. Top Level Parts List
Remove the parts from the main bag and separate each individual parts bags.
ITEM
QTY
PART NO.
DESCRIPTION
1
1
DBR836-KIT
Clock Display Board PCA parts kit
2
1
CLK036M-KIT
Clock Main Board PCA parts kit
3
1
2217625
Real Time Clock (RTC) Module DS3231
4
1
CLK036HDW-KIT
Final Assembly Hardware
5
1
CLK036ENC-KIT
Enclosure Acrylic 6 Piece
6
1
54-660
AC to DC Power SupplyWall Adapter Single
Output 5 Volt 1 Amp 5 Watt 2.1mm Conn

DIGITAL CLOCK MODEL CLK036
GEKCO INC. Rev 1.0 5
3.2. Display Board Parts List
Clock 036 Display Board PCA parts kit, DBR836-KIT
ITEM
QTY
PART NO.
DESCRIPTION
1
1
DBR836-PCA
LED DisplayModule Assembly7-Segment 8 Digit
0.36”
2
1
131-1X05
Connector Header Male 1 row of 5 pins
3
2
255-25511
Hardware Standoff Nylon M3 x 12 mm
4
4
255-29341
Hardware ScrewNylon M3 x 0.50 mm Thread,
6mm White
1
2
3 4
3.3. Main Board Parts List
Clock 036 Main Board PCA parts kit, CLK036M-KIT
ITEM
QTY
REFDES
PART NO.
DESCRIPTION
VALUE
1
3
C4,C5,C6
20-104
Cap mono Cer 50v radial lead
0.1UF
2
2
C1,C2
21-220
Cap mono Cer COG radial
lead
22pF 100v
3
1
C3
26-102
Cap elect alum radial lead
10uF/16v
4
1
Y1
404-160
Crystal HC49
16.00 MHz
5
1
D1
55-62
Diode schottky rectifier
1N5817-T
6
3
SW1,SW2,S
W3
64-1839
Switch MomentarySPST
7
1
SW4
64-1827
Switch Momentary5mm H
8
1
J5
131-1X05S
Connector Header Female
1 row of 5 pins
9
1
J2
131-1X06RA
Connector Header Right Angle
Male 1 row of 6
pins
10
1
J3
131-1X05RA
Connector Header Right Angle
Male 1 row of 5
pins
11
1
J1
134-002
Connector Power 2.1mm PCB
Mount
12
1
RN1
95-103
Res network 6 sip
10K 5 Res SIP
Package
13
1
X1
434-311
Socket IC
Dip28-300
14
1
U1
444-361-01
IC Microcontroller
Programmed
Part CLK036
V1.01

GEKCO DIGITAL CLOCK P/N CLK036 ASSEMBLY & OPERATION MANUAL
6 REV 1.0 GEKCO INC.
15
1
LS1
220-1420
Audio Piezo Transducer 30V
16
1
81-180912C
Printed Circuit Board
Main Board
1
2
3
4
5
6
7
8
9 10
11
12
13
14
15
16

DIGITAL CLOCK MODEL CLK036
GEKCO INC. Rev 1.0 7
3.4. Final Assembly Hardware Parts List
Clock 036 Final Assembly Hardware parts kit, P/N CLK036HDW-KIT
ITEM
QTY
PART NO.
DESCRIPTION
1
2
255-25511
Hardware Standoff Nylon M3 x 12 mm
2
2
255-29346
Hardware ScrewNylon M3 x 0.50 mm Thread,
16mm White
3
2
255-29347
Hardware ScrewNylon M3 x 0.50 mm Thread,
20mm Black
4
2
255-876
Hardware Spacer Round 0.25" Hole Size #4
5
2
255-877
Hardware Spacer Round 0.375" Hole Size #4
1
2
4
5
3

GEKCO DIGITAL CLOCK P/N CLK036 ASSEMBLY & OPERATION MANUAL
8 REV 1.0 GEKCO INC.
3.5. Enclosure Parts List
Clock 036 Enclosure kit, P/N CLK036ENC-KIT
ITEM
QTY
PART NO.
DESCRIPTION
1
1
86-18111901
Front Panel Acrylic 3mm Transparent Red
2
1
86-18111902
Back Panel Acrylic 3mm Clear
3
1
86-18111903
Top Panel Acrylic 3mm Clear
4
1
86-18111904
Bottom Panel Acrylic 3mm Clear
5
1
86-18111905
Left Side Panel Acrylic 3mm Clear
6
1
86-18111906
Right Side Panel Acrylic 3mm Clear
1
5
6
2
3
4