Operation

A timing signal is sent once per second throughout the show to all the SmartRails. Even though the SmartRails have different clocks, each with up to 1% errors, they are all re-synchronzed once per second so they never differ by more than 1/100 second.



Audio

The headphone jack on the laptop is connected to either a small FM transmitter ( Ramsey Electronics ) or an amplified sound system. The laptop plays the audio for the show and sends a timing synchronization signal to the SmartRails to keep them in sync with the music.



Improved accuracy

I know how to improve the timing accuracy to 1/1000 second. I can calibrate the one clock on the bus controller that generates the heartbeat signal and then use the heartbeat itself to drive the clocks on the SmartRails.

I could have done that last year but was reluctant because of some technical details. Now I have those details better understood but I am still reluctant to change because the difference between 1/100 accuracy and 1/1000 accuracy seems moot. I have personally measured variation in lift times among identical shells to be in the 1/10 second range.