Add in a simple 555 timer circuit for control and a power supply for the variable board and your all in!
I will have to get my hands on one to get it all hashed out but an Improved schematic would be a nice addition. If anyone found one please let me know and post it below. Going off a youtube video sucks. After a bit of research, I found a hint at what the nice guy on this page:
has found. An IC labeled Part number AN9DB07SB 929S6E02
I deduce it is a .........