I am making a prototype of a meditation alarm clock.
I am using an arduino nano.
With a rotary knob (potentiometer) I will choose how many minutes I want to meditate. 10, 20, 30, 40, 50 or 60.
For each choice there will be a LED turning on. So in total 6 LEDs. These LEDs need to be able to blink/pulsate (fade in and out) to show how many time there is still to go. For instance if I still have 25 minutes to go, the '30 minute' LED will blink. If I have 1 to 10 minutes to go the '10 minute' LED will blink.
So this I can do with the 6 PWM pins ~3, ~5, ~6, ~9, ~10 and ~11
But now I also want to play the sound of a gong at the end of the meditation. So I looked up and see that I can use an SD card and amplifier to do this: Simple Arduino Audio/Music Player with SD Card
Only problem now is that this solution also needs PWM ports, namely 3, 9 and 11.
So now I don't have enough PWM ports.
Does any of you see how I can make this prototype using 1 arduino nano?