During the past couple of months, I've been playing around with my bell siphons. Back in 2012 when I was setting up the geodesic dome, I added a small cup to the breather tube to aid with the stopping of drain cycle. This has been working quite well but I've never liked having the cup as a separate piece since it's a bit annoying to insert bell while holding the cup in place. (Original video: https://youtu.be/4hHRe3KJfoY)
This past summer I invested in a 3D printer for a contract job and started having some fun designing some enhancements for the greenhouse with the revised bell siphon being one of the improvements.
There's really nothing new with the overall functionality, just integrating the cup into the bell housing so it's all one unit. Also, is a small improvement to Afnan cup that is used on the stand pipe to help get it started quicker.
This is a lengthy and detailed video because I wanted to cover all the functioning basics of a bell siphon in action. I also invested in a camera that could shoot at 240 fps so you could see how the siphon starts and stops in slow motion. The siphon break is so fast it can be difficult to see how it operates in real time.