I've been messing around with chastity since high-school (maybe a bit earlier).
I am an extremely engineering-oriented person, and I have built 15+ different prototype chastity belts in my life.
Originally, they were uncomfortable, not discreet, and ineffective.
But, I've been improving my design slowly over the years. My most recent belt is shown below:
Here's a picture of it while it was being worked on