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Detailed entries for one subject from the INDEX TO HOW TO DO IT INFORMATION.
Click on a see also (sa) or tracing (xx) to view detailed entries about a related subject.
The entries are in alphabetical order by magazine name and then in chronological sequence.
To obtain a copy of any magazine article contact your local public library or the publisher.

xx   LOCK

Electronic combination lock circuit sounds an alarm if the wrong button is pushed. Est. cost: under $10.
CQ. THE RADIO AMATEUR'S JOURNAL Jan 1979 (v.35#1) pg. 100

How to activate an electric door strike using the X-10 control system. This allows a locked door to be opened without retracting the latch bolt.
ELECTRONIC HOUSE Sep-Oct 1990 (v.5#5) pg. 6

Electronic door locks. How they work and how to wire an electronic lock to your home controller.
ELECTRONIC HOUSE Jul-Aug 1995 (v.10#4) pg. 54

Digital, combination-lock circuit uses a keypad to activate a garage door, electric gate, electric locks, etc. Est. cost: $23 (kit).

Digital combination lock. Keyless electronic entry system uses a keypad to control a 12-volt solenoid which unlocks the door.

Combination lock is electrically operated by pushing four buttons in the right order, otherwise an alarm sounds.
ELEMENTARY ELECTRONICS Nov-Dec 1968 (v.7#2) pg. 41

Electrolok. An electronic combination lock requires 5-digits to be entered in the correct sequence. Use to control any electric device.
ELEMENTARY ELECTRONICS Nov-Dec 1979 (v.19#6) pg. 44

Electronic combination lock features 512 9-bit code combinations.
HANDS-ON ELECTRONICS Summer 1984 (v.2#1) pg. 73

The Compulock, a digital keypad combination lock that can be used anywhere that you would use a key-operated switch (alarm systems, electric door locks, etc.). Est. cost: $25.
HANDS-ON ELECTRONICS Mar-Apr 1986 (v.3#2) pg. 57

Electronic combination lock/alarm control. Est. cost: $45.
HANDS-ON ELECTRONICS Feb 1987 (v.4#2) pg. 38
Added Info HANDS-ON ELECTRONICS Jul 1987 (v.4#7) pg. 6

Electromagnetic door locks. Advice on selection and installation.
HOME MECHANIX #755 May 1991 (v.87) pg. 20

Tip: How to devise a secret code to etch on casings of combination locks so you'll never forget the combination, but no one else will be able to figure it out.
HOMEOWNER Jul-Aug 1985 (v.10#6) pg. 30

Circuit for an electronic combination lock. Up to 10,000 combinations using 5 switches. Use it to operate another circuit or electrically operated lock. Est. cost: under $10.
MODERN ELECTRONICS [1] Feb 1978 (v.1#1) pg. 50

Electrolock, a battery-powered keyless lock. Dialing the correct combination activates a solenoid which opens a barrel bolt.
POPULAR ELECTRONICS [1] Jan 1966 (v.24#1) pg. 60
Added Info POPULAR ELECTRONICS [1] Mar 1966 (v.24#3) pg. 10

Sequence operated lock. An electronic lock with seven buttons which must be pushed in the proper order for the lock to open.
POPULAR ELECTRONICS [1] Jan 1967 (v.26#1) pg. 73

Electronic lock is keyed by a modulated light beam operating at 2000 flashes per second. The "key" is built into an ordinary pen-light flashlight.
POPULAR ELECTRONICS [1] Oct 1968 (v.29#4) pg. 43

Keyless, electronic combination ignition lock for a boat.
POPULAR ELECTRONICS [1] Jul 1970 (v.33#1) pg. 40

Electronic lock uses 3-digit combination. Numerical grouping, two timing circuits and a penalty fixture make "cracking" it difficult.
POPULAR ELECTRONICS [1] Jan 1971 (v.34#1) pg. 42
Added Info POPULAR ELECTRONICS [1] Dec 1971 (v.35#6) pg. 89

Electronic combination lock offers up to 10,000 differnt combinations of 4-digits. Operates on 117-volt or 12-volt.
POPULAR ELECTRONICS [1] Aug 1971 (v.35#2) pg. 51

Electronic combination lock works on 12-volts. Uses a 5-button combination for 120 possible combinations. Can be expanded to more buttons.
POPULAR ELECTRONICS [1] Nov 1971 (v.35#5) pg. 53

Electronic combination lock has ten keys. It is capable of 30,240 combinations. Uses a five digit code pattern. Code must be entered within ten seconds. Est. cost: $20.
POPULAR ELECTRONICS [1] Nov 1973 (v.4#5) pg. 51

Twelve button electronic lock must be pushed in the right sequence and within the right time limit in order to activate an electric circuit. Use for cars and boats in place of keys.
POPULAR ELECTRONICS [1] Apr 1977 (v.11#4) pg. 48
Correction POPULAR ELECTRONICS [1] Jul 1977 (v.12#1) pg. 7

The versatile keypad. How to interface decimal and hexadecimal keypads to digital circuits. How to debounce the mechanical switch (key). Typical uses include computer data entry, electronic combination locks and a controlled pulse generator.
POPULAR ELECTRONICS [1] Aug 1978 (v.14#2) pg. 58

Circuit for a digital combination lock for a car's ignition switch.
POPULAR ELECTRONICS [1] Oct 1978 (v.14#4) pg. 78

Use your TRS-80 computer as a combination lock. Program plus simple circuits to control doors, appliances, and telephone lines.
POPULAR ELECTRONICS [1] Mar 1980 (v.17#3) pg. 70

Electronic combination lock uses rotary switches to prevent unauthorized use of electric-powered equipment.
POPULAR ELECTRONICS [2] Sep 1989 (v.6#9) pg. 24

Keypad sequential switch is a simple way to add an electronic combination lock to your security system. Four switches must be closed in the correct sequence and within a time limit.
POPULAR ELECTRONICS [2] Jul 1990 (v.7#7) pg. 25

Digital entry lock. Digital combination-lock circuit is operated from a keypad and can control any electrically-operated device (such as a garage door opener, electric lock, etc.).
POPULAR ELECTRONICS [2] Nov 1990 (v.7#11) pg. 61
Correction POPULAR ELECTRONICS [2] Jan 1991 (v.8#1) pg. 4

Keyless lock circuit is built around this sequential digital switch circuit that uses a four-bit latch and four-input NAND gate.
POPULAR ELECTRONICS [2] Dec 1990 (v.7#12) pg. 24

Electronic combination lock circuit requires that three numbers be entered (via rotary switch) in the correct sequence.
POPULAR ELECTRONICS [2] Nov 1991 (v.8#11) pg. 73

Build a digital combination lock. Use a keypad to enter a three-digit code which controls an electric lock.
POPULAR ELECTRONICS [2] Jul 1994 (v.11#7) pg. 70
Added Info POPULAR ELECTRONICS [2] Apr 1995 (v.12#4) pg. 30

Electronic locks. (1) Simplified digital lock. (2) Jack lock uses a plug-in headphone jack to activate. (3) Frequency-based lock uses a tone-generator circuit as the "key".
POPULAR ELECTRONICS [2] Apr 1995 (v.12#4) pg. 29
Added Info POPULAR ELECTRONICS [2] Oct 1995 (v.12#10) pg. 73

Voice recording and playback. Using the ISD1000A Direct Analog Storage Technology integrated circuit to construct a variety of circuits capable of storing and playing 20-seconds of audio. Part 2. Includes a tone-controlled lock and a tone generator.
POPULAR ELECTRONICS [2] Aug 1995 (v.12#8) pg. 74

Electric garage door lock requires you to set each of four (or more) rotary switches to the correct position before trying to raise the door.
POPULAR MECHANICS May 1981 (v.155#5) pg. 132

Push-button electronic lock circuit protects power tools from children.
POPULAR SCIENCE Dec 1971 (v.199#6) pg. 98
Correction POPULAR SCIENCE Feb 1972 (v.200#2) pg. 10

Circuit for an electronic digital combination lock requires that a 7-digit number be entered within a fixed period of time.
RADIO-ELECTRONICS Feb 1981 (v.52#2) pg. 88

Electronic locks. A look at how two binary-lock circuit modules work.
RADIO-ELECTRONICS Jan 1985 (v.56#1) pg. 85

Home security system. Low-cost home alarm system features a digital combination lock, optional display circuitry, and simple installation. Can also be used as an automobile or marine intrusion alarm, an ignition combination lock, or both. Multiple output contacts accommodate devices such as a siren, automatic telephone dialer, and floodlights. Part 1.
RADIO-ELECTRONICS Dec 1985 (v.56#12) pg. 61, 86

Home security system. Part 2.
RADIO-ELECTRONICS Jan 1986 (v.57#1) pg. 49, 75

Electronic combination lock is activated by an electronic "key" you carry with you. There is no keypad required.
RADIO-ELECTRONICS Nov 1987 (v.58#11) pg. 107
Added Info RADIO-ELECTRONICS Feb 1988 (v.59#2) pg. 14

Digital keyless entry system is built around Motorola's popular 68705 microcontroller. It accepts keypad input and then energizes an electromechanical door latch after the proper entry code has been entered. Est. cost: $75.
RADIO-ELECTRONICS Mar 1990 (v.61#3) pg. 71

Electronic Dial Lock. Telephone dial and electronic circuitry provide a keyless lock for doors. Est. cost: $25.
RADIO-TV EXPERIMENTER #789 Jun-Jul 1966 (v.20#3) pg. 63

Electronic (digital) lock uses push buttons to enter a 6-digit number sequence. Est. cost: $25.
SCIENCE & ELECTRONICS [1] Oct-Nov 1970 (v.28#5) pg. 61

Electronic lock protects anything that runs on electricity. Correct combination of 5 push buttons must be entered for lock to "open".
SCIENCE & MECHANICS Sep-Oct 1982 pg. 113