He linked back to mine a couple times and used some of my photos, but he used a different sensor type that's more similar to the EZABL and made a few other small changes along the way.

If you follow mine, use the Parts List at the top for reference but shop around. My website auto updates the prices from Amazon every hour and some of those are way more expensive right now than they used to be.

If you don't mind waiting for shipping from China, you can get the Optocoupler for $0.83 cents here. The sensor I used can also be found here for $7.99, but you can really use any proximity sensor you want and there are better ones out there.