Last night I finally got some time to get some prototyping done. I figured that I should start with a regulator circuit so that I have smooth power for using with op-amps. I will build a more efficient and permanent supply when I need it a bit more but using what was on hand I have a half reasonable output from this hobby train controller that was sitting in the garage.
Just about to start work on the triangle wave generator from this page.
EDIT: Just finished compiling LFS on my server so I should have more time to work on this.