Take that astable (blinking) 555 LED project and beat it to death with a club! A short definition of astable: Always changing state. not stable in either the on or off state.
You can start by building the circuit as given in the description of a project and then research the astable 555 configuration
Here's a simple calculator you can use to verify what you see with the various component values
http://www.ohmslawcalculator.com/555-astable-calculatorHere is a Wiki re: the operation of the chip itself:
https://en.wikipedia.org/wiki/555_timer_IC#AstableIt is worth knowing how the 555 operates and it is a pretty easy circuit to learn. A capacitor charges up and at some point along the capacitor voltage curve, the internal flip-fflop changes state. The capacitor then discharges and at some point on the way down, the flip-flop changes back again.
Plan to spend some time with the circuit, chip description and calculator. As a first project, it is going to take a while to really understand what's going on. The more or less advanced math in the Wiki doesn't help. Use the calculator...
Maybe a regular datasheet will help:
http://www.ti.com/lit/ds/symlink/lm555.pdfSkim it at first just to find out where various subjects are covered. Then see how the pin description lines up with the circuit you built. Try to figure out what the circuit does with the various pins. Look at page 10 where astable operation is covered. Note that R
L is shown in two configurations: The dashed load resistor uses the timer to provide ground to the load that is already connected to Vcc on one end. The plain R
L is set up for the 555 to provide Vcc to a load that has one side grounded. Either will work. In fact, I think you can substitute a resistor and LED for both R
L configurations. I don't know what voltage you are operating at but if I were doing this with 5V Vcc, I would probably use something like a 470 Ohm resistor and a standard Red LED. At 12V, I might try 1K. Neither configuration is going to overdrive the LED. Or use what your circuit shows.
If you spend a solid day playing with the circuit, changing resistor and capacitor values, reading through the documentation and just reflecting on what you see, you will learn a lot.
Then tie a monostable 555 to the output of an astable 555. This allows you to define a particular pulse width with the monostable that is independent of the operating frequency of the astable. Within limits, of course.
Revisit the project when you get a scope. There is a lot to learn about the capacitor charging voltage that is overlooked in the first pass and, while easy to describe mathematically, really jumps out when you see the capacitor voltage versus output level changes. Then you will really understand the magic!