What i'm trying to do is convert a device's spst button output.Instead it will have two selectable output states.State #1 will output one low level each time the button is pressed(or a continuous low when held closed).

State #2 will output a continuous 010101 pulse when the button is held closed .Both modes are selected via the spdt switch .The pot is just there to select between pulse speeds.

The completed circuit will go inside a small project box and the user plugs his device into this box ,then the box/circuit plugs into the user's system.The device has two spst momentary buttons .

So far i've come up with the circuit below.

There is a 3rd state i've just thought of,and that's an auto state.Where no button needs pressing to output a continuous 0101 pulse, an auto mode.How would this be possible to select ?I also have access to some 74hct74's ,mc14052b's, ,74hc157's and 4001B's .

 

This would work ,and support 2 devices ,(4 buttons in total) with just one spdt operating the 74hc157 ?

 

Would this work? ,and support 2 devices ,(4 buttons in total) with just one spdt operating the 74hc157 ?

 

Your astable circuits will be good for blowing power supply fuses.