Beginner concepts: 555 push button toggle

PIC, AVR, and Arduino are ubiquitous in projects these days and a lot of the time it’s easy to over-complicate things with their use. In this case, [Tod] wanted to use a momentary tactile switch to turn something on and off. Instead of going with a microcontroller he built the circuit around a 555 timer. What he really needed in this case is a flip-flop but lacking a chip for that he went with the 555 because it has one built-in. Three resistors and a capacitor later he’s in business, adding another resistor and a transistor to deal with the load switching. We’ve embedded video of the circuit controlling an LED after the break. This IC ends up in a lot of projects so dig through your parts bin and give this circuit a try.

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Parts: Tactile switches for your next project

Electronics parts can be a pain to choose. It’s often hard to tell from manufacturers’ datasheets if a part will fit your design. We auditioned six different tactile switches to find a cheap button to use in upcoming projects. A tactile switch, also called a momentary button or push-to-make switch, is commonly used for input and microcontroller resets. This type of button creates a temporary electrical connection when pressed.

Footprints for most of these buttons are available in the Cadsoft Eagle library switch-tac, or in the Sparkfun parts library under TAC_SWITCH. Buttons in the image above are discussed from left to right. [Read more...]