John Wolff is a retired electrical engineer from Melbourne, Australia. His background is mainly in electronic instrumentation, control systems, and computers. He has worked in private industry, public utilities, and academia for over 40 years, most recently as an IT manager in a government research laboratory. For a second full-time job he has been a sole parent to two teenage kids. For hobbies, he tinkers with pianolas and mechanical music, reverse-engineers antique calculators, and helps out at the local woodworking club.