Relay, originally uploaded by Black Heart Industries.

I finally have some time to work on this project. The minutes section will be controlled via the rotary switch. It has 30 positions, each with 4 switches. Row one will be used for the ones indicator: 0-9. Row 2 will be used for the tens indicator: 0-2. Row 3 will also be used for the tens indicator: 3-5. At one complete rotation a leaf switch is engaged which can be used to control a relay. This relay switches from row 2 to row 3. I was a bit confused on how to do this with relays & only one pulse. I found the solution here: http://www.emil.matei.ro/onof2.php
A good read and best diagram I’ve found to explain this operation. Version 1 is the one that I’m going to use. No ‘load’ is necessary as the relays I’ll be using have 3 switches, each has a normally open & normally closed contact. The pulse to trigger the rotary switch will come from a digital clock that comes in a tube like package. The current idea for the hours section is to use a solenoid to control a cam with 12 sections. Each section is to have a micro switch. If I can find a 12 section motorized switch, maybe from a neon sign or telephone system, I may use that instead. Next step is to put together the power supply & test the pulse generator. Also thinking about aesthetic design & how to set time. There’s still much to be decided & many problems to solved.