A momentary switch that is recessed below an outside frame is needed. The switch button should be lit with a red light. The unit should be approximately 4 inches square.
The switch is a modified wobble switch that uses 4 red LEDs in a multivibrator circuit to alternately flash two pairs of LEDs. The button is a 3.25" reflector mounted on a Lexan disk. The second photo shows the switch with the red reflector removed. The 4 LEDs, the 3 suspension bolts for the button and the doorbell switch can be seen in the photo. The third photo shows the battery pack and electronics board. The three holes shown in this photo are for adjusting the button travel. If the button goes out of adjustment, it can be corrected with a socket wrench.
The wooden box is 5" x 5" x 3.25". The 4 C cell batteries should last approximately 410 hours.
Refer to the drawing below for construction details. The holes in the button and upper and lower base must be precisely aligned. 5/16 pilot holes should be drilled in all locations with the three pieces stacked. Place a nail in the center hole and one other hole to maintain alignment while drilling the other holes. The 6-32 bolts are self-threaded into the Lexan button since the hole that is drilled is slightly undersized. The lock nuts are adjusted with a socket wrench so that the button sits firmly on the doorbell button without significantly depressing it. Notice in the picture that holes are drilled in the bottom of the battery holder to line up with the lock nut adjusting holes in the base.
The four LEDs in the flasher circuit are sandwiched between the upper and lower bases and are held firmly there. Three sides of the switch housing are glued together and the forth side held by screws so the base can be removed if the LEDs need to be replaced. The photo shows the installation of the 4 C cell battery holder.
1) Do NOT use a lighted door bell button - It will not work.
2) Optronics reflector RE-21R from Advance Auto Parts works well.
3) Use a garden hose washer for the spacer instead of cutting one from 1/8" hardboard.
RCRV designer is John Wauer, and was requested by New horizons, Mark Beason. The project was begun May 28, 2004 and completed Jul 21, 2004.
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