This flashlight has three different modes of operation, regular flashlight, flashing LEDs, and sound-operated light.
Most small AA battery type flashlights use two cells, but that does not supply quite enough voltage for these LEDs, so parts from two plastic flashlights were joined together to allow room for three AA cells. The LEDs were mounted in the head of the flashlight with epoxy, with the four white ones in the center pointing forward surrounded by the six flashing LEDs pointing outwards. A small slide switch was added to select either white light or flashing colors.
Two double AA battery holders were attached back-to-back for a total of four AA batteries. Three small circuit boards were constructed, one for the switches and controls, one for circuitry, and one for the LEDs themselves. These were the stacked on top of each other and wired together attached to the battery holders. Plastic tape to protect the electronics and a small plastic base was also installed.
The display uses four white LEDs for regular flashlight use, four RGB flashing LEDs and eight single color LEDs powered by two flashing circuits for the flashing mode, and three regular RGB LEDs and nine single color LEDs for the sound-operated display in the center. The first picture below shows the four white LEDs, the second and third are the flashing LEDs, and the last is the flashing LEDs with all of the sound-operated LEDs on as well.
The sound-operated mode uses a five-step discrete bar graph circuit to drive a multi-LED display. An electret condensor microphone and preamp supplies the audio signal to the display circuit. The pictures below show the level of light getting higher with the audio signal, but what they don’t show is how the color of the light changes from dull purple to blue, green, red, orange, and finally yellow and white as the sound gets louder. It is a very nice effect, almost looking like a flame dancing to the music!
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