RGB LED Color Sequencer - Without a Microprocessor

by qs in Circuits > LEDs

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RGB LED Color Sequencer - Without a Microprocessor

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Display the color combinations of color LEDs without using a microprocessor.

Using a single logic chip which costs under 50-cents, you can make a simple color cycle display for RGB LEDs. The multiple taps along the top are used to 'program' the display for sequence and brightness.

The Parts

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You will need:

RGB LED - I used one purchased here. This is a common anode version, so if you have a different configuration, you must adjust the connections.
1 x 74HC04 Hex Inverter IC chip (p/n 771-74HC04N, by NXP is 30-cents at Mouser)
3 x 0.1uF capacitors
R1 - 10M-ohm resistor
R2 - 6.8M-ohm
R3 - 3.3M-ohm
R - 12 pcs of 100-ohm resistor for the Programming tree. I used 120-ohm resistors which I got free.
2 x "AA" batteries and suitable holder.

Perfboard, wire, supplies, etc.

I've also used sockets for the IC and the LED, which I've found to be quite sensitive to heat.

Assembly

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Here is a diagram showing the parts and how they are wired.

The yellow lines are jumpers connecting pins 2&13; 4&11 and 6&9 on the underside. The 0.1uF capacitors are similarly connected under the socket (pin 1&12; 3&10 and 5&8). Make sure the wires do not touch.

The Jumper wires can be inserted anywhere on the 'programming panel' to adjust the brightness and speed of the color changes.

The Final Touch...

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Now, slip a length of heat-shrink tubing over the LED as a light diffuser, and you are done!

Light on!

More LED circuits are here on my website.