Simple and well-known circuit. Useful for making locks and other things.
Normaly, 1 button press = 1 action (We will name an action a modification of the state of the Binary Counter output, which is the green led in the examples below).
A binary counter adds more possibilities. So with one SR Latch (on the pictures below there are three) 1 button press = 1 action, with two SR Latches 2 button presses = 1 action, with three SR Latches 4 button presses = 1 action, and so on.
However, keep in mind that many current-receptive blocks like doors only react to the rising edge of the signal. Therefore, you need two actions, which means two modifications of the state of the Binary Counter output, to make the door move.
The following two slideshows show two 3 SR Latches Binary Counters.
- When all three leds are lit (ignore the one above the button in the first slideshow), you have to press four times the button to modify the green led state, and thus having an action.
- When all three leds are unlit (ignore the one above the button in the first slideshow), you have to press four times the button to modify the green led state, and thus having an action.
Concerning binary numbers, you have to read them form right to left, again ignoring the led above the button in the first slideshow.
Place SR Latches on the wall and connect its ouputs with next one's clock (its on you how much SR Latches you will use). Then connect SETs and RESETs with NOT gates. On the first clock connect button, and on the last output the thing you want to control (on picture green LED). You can also put some devices (on picture red LEDs) between SR Latches.