Electric eye rings fire bell – Opens garage door

Simple garage door project from “How To Build It” 1932 – “ANYONE interested in experimental electricity can gain a great deal of knowledge and pleasure from the construction of this light-sensitive selenium cell, and have also a handy electric eye that will actuate through a relay any bell, motor or magnet circuit in the bargain.

First, in making the cell, notch the long edges of a piece of mica with about twenty teeth, and drill small holes in the corners, as illustrated in Fig. 3. Next tie the end of a length of No. 18 wire to one pair of holes in the mica and wind on approximately 10 turns, using every other notch along both top and bottom edges. Pull tight and tie the opposite end of the wire in the holes at the opposite end from where it was first tied. Do the same with the second piece of wire, tying the ends in the opposite corners. Fig. 3 will show this plainly. Then test out each winding as illustrated in Fig. 4. If the two windings touch at any point the lamp will light.” – Link.

Modern garage door hackery…:

• HOW TO – Make a garage door monitor – Link.
• LED flashlight from garage door remote – Link.
• HOW TO – Build the ULTIMATE Garage Door Monitor – Link.
• HOW TO – Replacing deadly garage door torsion springs – Link.
• HOW TO – Make a garage monitor – Link.
• HOW TO – Build your own garage locator device – Link.