use 1 pin from arduino for bi color LED?

Using Arduino LEDs and Multiplexing
1

Is it possible to use only 1 pin of an arduino to run a bi color LED?

2

What's the LED? if it's 3 pins no..

3

I'm thinking of using L-59EGW but since 3 pins is a no no, what do you suggest I use?

4

2 pins from your arduino instead?

5

I'm trying to do a 2 digit 7 segment display made from LED. And I want them to change color.
Since the seven segment requires 7 pins to light up one color it needs another 7 for another color; I need 28 pins?! :cold_sweat: noo!

Could you suggest anything on how to lessen the pins?
Can I put a switch or something to trigger what color I use?

6

You can use the arduino to multiplex and control multiple leds or use shift registers

I guess you could buy 7 segment driver ics and pass in the value with your arduino.

Or a combination, 3 pins to a shift register, they inturn control a driver.

There's several options...

7

arduinoTime:
Could you suggest anything on how to lessen the pins?
Can I put a switch or something to trigger what color I use?

That depends on how you want to select the color.

If the whole display is the same color you can connect the anodes to Arduino pins (via suitable resistors of course) and tie all the cathodes of each color to an NPN transistor (two transistors). The transistors select the color.

If you want individual color control on each segment then you need shift registers.