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Case #90: Ken Put an End to Expensive Front-End Damage
Design News Staff -- Design News, September 24, 2006
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.
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Read Ken Swanstrom's complete instructions on how to build your own Garage Locator Device (PDF). |
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| 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 | ||
| Brass contact tab for end of laser pointer | ||
Talkback
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To answer some of the comments:The laser pointer is mounted on brackets to allow side-to-side...
- 2006-29-9 15:37:11 EDT -
interestin...
- 2006-28-9 03:54:31 EDT -
great...
- 2006-28-9 03:46:27 EDT -
Where does the laser point (car hood, bumper)? Where is it mounted (ceiling pointing down, wall...
- 2006-27-9 10:36:25 EDT -
Greetings,I live in an area where power failure is a daily occurance. Plus, I do not have a...
- 2006-27-9 06:40:35 EDT
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