Hello, our Museum got ahold of a retired railroad signal and would like to set it up to cycle through its 3 indications (green yellow, red) the green cycle would be the longest length of time, then it would repeat the cycle. The bulbs in the signal are 12volt incandescent bulbs probably similar to a turn signal bulb in a car, maybe 15 watts? The signal is position light signal, so it displays a row of 3 bulbs vertically, diagonally or horizontally depending on what level of permission the signal is giving. This means that the center bulb is on no matter which indication is given.
My thoughts are to wire the center bulb directly to a power source and then take the output wire from the center bulb and feed that to the 3 circuits that have 2 more bulbs in series. Then from these I would route the return power through 3 ground paths. This is why I might need a circuit that simulates a 4 position motorized rotary switch. This would give the green circuit ground for 2 switch positions, then yellow for one, and red for one. Then the cycle would repeat.
I'm not sure exactly which path to go, I'm toying with the idea of a DC control timer like a 555 controlling a relay, but am at a loss how to make a simple controller that can control 3 wires through relays. Maybe some kind of sequential IC like a flip-flop?
My thoughts are to wire the center bulb directly to a power source and then take the output wire from the center bulb and feed that to the 3 circuits that have 2 more bulbs in series. Then from these I would route the return power through 3 ground paths. This is why I might need a circuit that simulates a 4 position motorized rotary switch. This would give the green circuit ground for 2 switch positions, then yellow for one, and red for one. Then the cycle would repeat.
I'm not sure exactly which path to go, I'm toying with the idea of a DC control timer like a 555 controlling a relay, but am at a loss how to make a simple controller that can control 3 wires through relays. Maybe some kind of sequential IC like a flip-flop?