Written by Kent Learned, 5 December 2019, originally posted to the Wonderland History Facebook group.
Part of the Plaza Shop project was to have a working / tolling clock tower. We had done some research and found a high quality clock mechanism from Switzerland, but the control system was around $4000 and the bell sounds that came with it sounded very artificial. It didn’t really sound very nice at all. Abrupt, cut short bell sounds, and a bit of a breathing sound.
After some searching of several sound effects libraries, we found some bells that sounded good. I took the sounds and edited them into believable sequences and then burnt them onto a CD. There were at least 16 tracks, including tolling on the quarter hours. I think there may have even been a few bell-peeling tracks, like from a church steeple, as well.
We then started working on the electronics to control the whole thing. Rod Nielsen got an old PC from the accounts department I think, and wrote some software to control the parallel printer port, and I built an electronic interface to drive the long data lines to the tower, as well as protect the computer from nearby thunderstorms.
Rod also created the software that looked at the clock in the computer and then played the right bell track at the right time. There was an option to allow you to choose whether it was a normal park day or a late night open park day. On a normal day the clock ran from about 7:00am to 7:00pm. On a late night day, the clock ran for 24 hours, but the bells were muted about an hour after closing. There was also another function, where if you entered the time on the clock face, it would send the correct number of pulses to correct the time on the clock face. Just some of the fun things you have to think about when you’re creating something.
Up in the tower, I had made another electronic box to drive the clock mechanism. It wanted alternating positive and negative electrical pulses to make the clock movement advance. So every time the computer sent out a minute pulse, my box up in the tower gave out a sequential positive or negative pulse to the clock motor and the motor advanced the clock hands by 1 minute. It was a very reliable system, and you could drive 50+ clock motors from the master computer. This is how they co-ordinate all the clocks in large public buildings or railway stations.
I think we had 3 clock faces and motors up on the tower. David Ward-Fear made new clock hands for the clocks, that had the right look about them. We put 4 of the Dino MkII speakers up in the tower. It was quite a cramped space behind those clock faces and was very difficult to work in.