Simple and easy timer counter using a 555. 2 decade or binary counters 2 bcd decoders and 2. Seven segment common cathode led displays
If you use binary counters you will get 0 through f (16 before the roll to next digit) for a total of 256. If you use decade you get 0 through 9 for a total of 99. Be sure of your math and which counter you are using and how to utilize those math skills.(various counter IC chips are available).
Use the push button to reset the counter.
You may want to add 1k resistor to the voltage of the chips to protect them if there not 9v tolerant. As well as the leds they are very likely not 9v tolerant.
