29/11/2025
How to control 9 LEDs with only 4 switches... It's really difficult... but with this idea, you can control 9 LEDs with just
4 switches .
The idea is that you select the LED number that you want to control by the 4 switches where the right , After selecting its number, you enter a passcode , which is 0, 2, 1.
But how do we determine the LED number that we want to control?
If the selector switch is on, its value is 1; if it's off, its value is 0. We determine the LED number by using this equation (No.selector*this value).
For example, if we have 2 selectors on (selector 1 and 3), we multiply each selector by 1 and add the results together:
4 = (selector 3 * 1) + (selector 1 * 1)
So, the LED that will be on is LED number 4.
https://wokwi.com/projects/393881367404704769
