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Case #90: Ken Put an End to Expensive Front-End DamageCase #90: Ken Put an End to Expensive Front-End Damage
DN Staff
September 25, 2006
3 Min Read
Not satisfied with the low-tech method of suspending a tennis ball from a string, Ken Swanstrom devised a better garage locator device from a laser pointer. This simple circuit is powered by a 6V dc wall wort, adjusting the output to yield 3V dc as a substitute for battery power. A CdS cell "looks" at the garage door opener light and actuates a relay, turning on the laser pointer when the garage door opens. And voila... no risk of front-end damage anymore.
Garage Locator Device
Amt | Part Description | Allied Part # |
|---|---|---|
1 | Resistor 180 ohms 1/4w | 832-0237 |
1 | Resistor 1k ohms 15-turn pot | 754-1061 |
1 | Relay 5V dc reed | 850-1550 |
1 | NPN transistor 2N4401 | 568-1946 |
1 | Diode 1N4001 | 266-0001 |
1 | Photoconductive cell | 699-9516 |
1 | Power supply 6V dc | 928-9625 |
1 | Terminal strip | 924-0100 |
Additional parts required | ||
Laser pointer(s) | ||
Perf board | ||
4" x 2" electrical box with cover (modified with various holes) | ||
Wire | ||
Fabricated parts | ||
Laser pointer ceiling brackets | ||
CdS brackets | ||
Dowel with brass screw |
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