Ultrasonic motion detector senses movement from 4- to 7-meters away and turns on an LED. Additonal circuitry can be added to turn on lights, alarms, etc. Est. cost: $30.
POPTRONIX HOBBYISTS HANDBOOK Winter 1996 pg. 87
Ultrasonic intruder alarm detects motion. Est. cost: $38.
POPULAR ELECTRONICS [1] Mar 1970 (v.32#3) pg. 57
Correction POPULAR ELECTRONICS [1] May 1970 (v.32#5) pg. 88
Build an optical motion detector alarm that detects motion through light changes. Use as a burglar alarm, plus a smoke and fire detector.
POPULAR ELECTRONICS [1] May 1980 (v.17#5) pg. 61
Motion detector circuit is built around a 4046 phase-locked loop IC.
POPULAR ELECTRONICS [2] Sep 1989 (v.6#9) pg. 89
Automated entry alarm circuit features a sensor that detects changes in ambient light and/or motion.
POPULAR ELECTRONICS [2] Feb 1990 (v.7#2) pg. 27
Using sound for detection and measurement. (1) Distance-measuring system acts like a simple radar system. (2) Motion detector is based on the Doppler effect.
POPULAR ELECTRONICS [2] Sep 1990 (v.7#9) pg. 82
Ultrasonic motion detector circuit uses two speakers (one to emit a signal and the other to detect the reflected signal).
POPULAR ELECTRONICS [2] Aug 1991 (v.8#8) pg. 74
Microwave motion detector security-system add-on works on the same principles as police radar. Est. cost: $20.
POPULAR ELECTRONICS [2] Oct 1993 (v.10#10) pg. 31
Motion-detecting alarm circuits. (1) Add a buzzer to a passive-infrared exterior light that sounds when the light is activated. (2) Changes in ambient light are used to latch a variety of DC loads. (3) Infrared transmitter and receiver to monitor a passageway.
POPULAR ELECTRONICS [2] Aug 1994 (v.11#8) pg. 24
Added Info POPULAR ELECTRONICS [2] Feb 1995 (v.12#2) pg. 30
More ultrasonic circuits. (1) CW (Morse code) transmitter. (2) Motion detector. (3) Proximity detector.
POPULAR ELECTRONICS [2] Jan 1995 (v.12#1) pg. 71
Correction POPULAR ELECTRONICS [2] Apr 1995 (v.12#4) pg. 4
Build an ultrasonic motion detector. Detects motion from 4- to 7-meters away. Can be adapted to activate another device (light, alarm, etc.). Est. cost: $28 (kit).
POPULAR ELECTRONICS [2] Mar 1996 (v.13#3) pg. 52
Tip on mounting passive infrared motion detectors and how the pulse-count concept is used to interpret motion.
POPULAR HOME AUTOMATION Jan 1998 (v.2#6) pg. 6
Use a motion sensor and siren to keep curious kids away from presents under a Christmas tree and/or to protect other areas of your home.
POPULAR HOME AUTOMATION Jan 1998 (v.2#6) pg. 42
Build this light sensitive security alert. Nearby movement will cause diffused shadows which are picked up by a photodiode and trigger the alarm. Est. cost: $25.
RADIO-ELECTRONICS Apr 1979 (v.50#4) pg. 44
Correction RADIO-ELECTRONICS Jun 1979 (v.50#6) pg. 6
Build this sonic motion-detector sensor suitable for use in a burglar alarm, door opener, etc.
RADIO-ELECTRONICS Sep 1984 (v.55#9) pg. 51
Build a micromotion detector that can count insect heartbeats. Relies on the use of minuscule magnets and a sensitive Hall effect transducer. Est. cost: $40.
SCIENTIFIC AMERICAN Aug 1996 (v.275#2) pg. 96