I want to show a program state with LEDs. There are 22 steps, each step is represented by an LED.
- only one LED is on at a time
- the sequence is set (forward or backwards).
I have only one pin left on my MCU, maybe two.
Basically, I'd like to have the pin work as a 'clock'. For every pulse, the "next" LED is switched on, all other LEDs are off.
I could use a clock to binary IC. (e.g. 74HC393 Binary Counter) This would create a nibble, which I could then feed into a multiplexer (e.g. 700-MAX336CPI+) which would switch one of its 16 outputs on at a time. (I can live with 16 steps).
I want to make it relatively cheap. I wonder if there is a more elegant solution. Maybe with a specialized IC, or if there is a solution with simple discrete components, oh, maybe I could even use a little servo to point at the right step… What comes to your mind?