I totally missed this.
The shield stays on with the delay. The HD Tuner could very well be off at this point, and AutoSense will still try to send commands, however nothing will happen, the go into the abyss. When the tuner is on again it would need a new power-up command to be sent. I wonder if you connect both red and yellow wires of the radio to constant power will this draw current when the radio is off? This is something I’d like to test, but maybe you can do it before me. If the current draw is minimal or none, then maybe keep it that way. The radio wouldn’t draw any power when off. I’d just have to make sure the power off command is sent before the Arduino cuts power. The only issue is the Arduino has no idea when the power will be cut, it just happens…
Maybe I could add a command to the power controller IC to send a “cleanup” signal to the Arduino before power is cut. You’d have to reprogram the Attiny on board the shield with the new software, but this could make sure the Arduino gracefully shuts things down before power removal and restores them when power comes back.
As for presets 6 isn’t enough 😉 I don’t have that many stations here that play good music 😛
It shouldn’t be difficult to add the ability to add more, I just wanted to start simple, get basics working somewhat then add more. It is on the list though.