Hello Bartosz and Kai,

Bartosz, the idea was to save port pins on the 80C51 IC. The project had over 15 railroad crossings total. The group wanted something simple and the same for easy maintenance down the line.

Kai, Your circuit is better. The chief reason is that both LED's can be off. I will play with the circuit and submit it to the group. The 50/50 on/off ratio is OK but with the other circuit a human being can't tell the difference with 5% equal components. There might be times when you want one say 70/30 on/off ratio.

The circuit was applied to a bell to complete a real railroad crossing. It was quite impressive to see a telephone bell hooked up to the flip flop being driven by a TIP32 transistor.

The mechanical inclined people found the circuit easy to work with and preferred it over a processor chip. They don't like the black magic you have to learn to make them work.

To overcome the problem with my circuit of one of the LED's being on I just put a green led with that one being on when the circuit is not flashing. The purest didn't like that idea at all. Now I can go back to them with an improvement. Thanks.

Thank you for your input. I will provide more feed back during the upcoming week.

Regards,

Charles Bannister