> Plus, things like cars were still hackable with a few transistors and passive components, you could make a customised indicator timer, or turbo timer or what ever, and it was probably way cheaper if you knew what you were doing.

I nodded when I read this, thinking, "Yeah, and what's the modern equivalent?" Everything seems so high level and complex, like CANBUS in the case of car, USB for PCs and of course so much is locked down.

Then I realised that kids could get a start sticking an LED on a GPIO pin from an Arduino. I believe a PI is basically a PC, but perhaps it could have a few such pins as well, if it doesn't already. PCs used to have parallel ports which served a similar function.

Then from blinking a LED they could incrementally add a few more circuits: 7 segment display, some counters, who knows. Even some analog stuff (to hell with harmonics) are possible -- and controllable from your laptop or phone over network.

Perhaps Evel Mad Scientists or Adafruit has a few things in this direction?