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CL-3 Digital Rotary Combination Lock

From black box to open-source project

CL-3 Digital Rotary Combination Lock
The CL-3 got designed and built way back at the end of the 20th century. It used an Atmel AVR AT90S1200 flash microcontroller with a rotary encoder to emulate a mechanical combination lock, triggering a relay when the correct combination was dialed. Back in those days, it was considered prudent to keep project development and design documents a closely guarded secret. Tin-lead solder was king and people were stockpiling food and weapons for the upcoming Y2K upheaval. Today we know better — open source is the way forward.
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Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.

Elektor recommends its business partner Eurocircuits as the company of choice for its own prototypes and volume production in selected cases.

Extra info / Update

Main features
6 digit operation (three 2-digit numbers in CW-CCW-CW sequence)
ATtiny2313 microcontroller
Optical or mechanical rotary encoder
Hidden/secure programming button
Free C code

Download the BOM list
The BOM (Bill of Materials) is the technically exhaustive listing of parts and other hardware items used to produce the working and tested prototype of any Elektor Labs project. The BOM file contains deeper information than the Component List published for the same project in Elektor Magazine. If required the BOM gets updated directly by our lab engineers. As a reader, you can download the list here.
Want to learn more about our BOM list? Read the BOM list article for extra information.
Component list
R1,R2,R3,R5,R6,R8,R9 = 100?
R4,R7 = 10k?
C1,C2 = 10nF
C3,C5,C7 = 100nF
C4,C6 = 100?F 25V radial
D1 = 1N4148
D2 = 1N4001
LD1,LD2 = 7-segment LED display, common anode (CA), h=10mm, Avago type HDSP-315L
T1 = BC557
IC1 = Atmel ATTINY2313-20PU, programmed, Elektor # 100026-41
IC2 = 7805
S1 = Tactile switch, 6mm, Multicomp type MC32830
S2 = rotary encoder, Alps type EC11E15204aE
K1 = 2-pin pinheader, 0.1 inch lead pitch.
K2,K6 = 10-pin (2x5) pinheader 0.1 inch lead pitch
K3,K4,K5,K7 = 3-pin pinheader, 0.1 inch lead pitch
RE1 = PCB mount relay, DPCO, 5VDC, Multicomp type HRS2H-SDC5V
PCB, 100026-1

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