Hi, these digit are nice to build a chronometer during the lesson P.E. running. What do I needs and how to build?
Basically, you need an number of digits and custom electronics based on a microcontroller which keep the time and send RS232 data to the digits.
As you can see, you need more than a basic understanding of electronics, so as we do not offer plug-and-play solutions we suggest you seek local help i.e. someone who can develop such a control circuit. Another option would be to use a PC to control the digits but once again this requires custom written PC software.