Today I have a pretty obvious Idea, but could not find someone that has done it anywhere: using a shift register as a cheap DAC.
The reason for this is that DAC's are not often found in your local electronics shop, opposed to these shift registers.
So, can an AVR such as an AtTiny send serial data to a shift register, which will contain a resistor ladder, therefore becoming a DAC? or does the shift register take too long to change state? What are the reasons this is impractical?