Here’s a 6 digit frequency counter by Yi, entered into the Open 7400 Competition.
During the Winter break my dentist convinced me that I needed to have my 2nd wisdom teeth removed. Having done this previously without much pain, I thought it would be a good idea. It turned out to be much more involved and I was out of commission for 2 weeks which was no fun at all. I was in bed most of the time, but one day I made myself get out of the house to buy the temperature controlled soldering iron that I’ve always wanted. I needed an excuse to use the soldering iron so I figured that I might as well as make a frequency counter which is something that I’ve always wanted, but lacked in my lab.