Building a 555 timer from discrete components

The 555 Design Contest shook a whole bunch of really creative circuits out of the trees, hence the 555-heavy content lately. While not technically part of the contest, [esalazar] wanted to know what made the 555 tick, literally! He started working on the project in a circuit simulator, then ultimately ended up building the three main logic blocks inside the familiar timer on pieces of copper-clad board. He’d built a 555 using discrete components.

While this isn’t 100% compatible with the classic 555 IC, it covers the basics pretty well, and [esalazar] gets extra-credit points for embracing the hacker spirit of seeing for himself how stuff works while documenting it well and citing his references.

555s for your mouse and R/C airplane

[lenny] decided to build a 555-based auto-firing mouse based on a 555 after seeing a similar PIC-based project we posted earlier. Lenny’s version is self-contained in one mouse without requiring a second mouse to act as the rapid-fire button. It uses only a handful of components, costs less than $5 to build, and doesn’t require any programming.

But then, [wfdudley] shakes things up a bit. He added a 4022 counter IC and some diodes to act as logical “OR” gates in order to create a unique blinking pattern (short-short-long) for the lights on a friend’s RC airplane. While this project involves more components, it’s definitely a trickier problem to solve with a 555 timer IC. We love seeing people choosing simplicity in design over popular off-the-shelf microcontroller frameworks as these two have done.

Don’t forget, the 555 Design Contest is still going strong, and you’ve got the entire month of February to submit your awesome designs. We wanted to highlight two of the more clever 555-based hacks that we’ve had in our backlog for a while, though.

Getting started with the Parallax Propeller

The folks at [gadget gangster] have been working on an excellent set of tutorials for getting started with the Propeller chip itself, the open-source Propeller Platform Modules and the Spin programming language that’s used to control things. All of the basics and a growing selection of more advanced topics are covered in gorgeous detail, with most of the tutorials containing helpful photographs and screen shots, source code listings and video walk-throughs to help you understand what the authors are talking about.

Parallax is not new to the microcontroller game. Almost two decades ago, their BASIC Stamp embedded microcontroller was the springboard for many tinkerers. The Parallax Propeller is an easy-to-use microcontroller that’s been gaining popularity for a while now. Several Propeller support modules have hit the market recently, providing power supply and interface functions to the Propeller similar to how the popular Arduino platform interfaces with AVR microcontrollers.

Oxyhydrogen water rocket

[cmwslw] built a soda-bottle water rocket that uses the ignition of oxyhydrogen gas to quickly expel the water, as opposed to the usual compressed air and water mixture. His project contains excellent documentation with photos and it builds on other articles he’s written about generating the flammable HHO gas used to launch his craft into the skies. Every aspect of this project uses items most of us have at home or could score cheaply at most hardware stores.

We love seeing projects that re-purpose everyday materials into something fun. Just be sure to dodge the missile pop bottle as it speeds back to Earth!

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