Lighthouse LED simulator
You can do this with one 555 and a flip-flop, plus a single PNP BJT (or p-channel MOSFET). Low output = ON. Toggle the FF with the 555 output. 

The 555 discharge resistor R4 gives you the 750msec 'ON' time. The charge resistor R1 + R4 gives you the 7.5 seconds or 1 second when paralleled with a second resistor (switched by the BJT) R1||R2 + R4. 

This is pretty easy. Use a FF compatible with your supply voltage (eg. 4000 series CMOS for >5V or 74HC for &lt;= 5). 

Like this (though I'd use a D FF with D tied to /Q rather than the JK Circuitlab has) 







simulate this circuit &ndash; Schematic created using CircuitLab

Or just use a 32-bit micro- using an RTOS should make it easy..