Nerd Out By Building This Giant 555 Timer for Your Projects
Learn about the 555 timer and how one maker was able to create a super-sized version of it, the Giga-Max 555.
The NE555 timer IC is a classic chip that has been around for decades and has many possible uses. Created in 1972 by Signetics, its widespread availability and low cost has lent itself to countless projects and beginner circuits. The 555's internal wiring is quite simple, consisting of just 25 transistors, two diodes, and 15 resistors, with eight external pins in a DIP package.
Operating Modes
As stated previously, the 555 timer is very simple, but it is still capable of some pretty impressive things. It operates in four modes: astable, monostable, bistable, and schmitt trigger.
Astable mode causes the IC to act like an oscillator, as it outputs a constant stream of square pulses over its OUT pin, and this can be changed based on a couple of external resistors and a capacitor.
Monostable mode makes the 555 output a pulse for a certain amount of time after a trigger, such as debouncing a pushbutton. The amount of time the OUT pin is active for is controlled by a single capacitor and a 91kOhm resistor.
Putting the 555 into bistable mode makes it act like a single bit of memory, where a signal can be sent to set it high or clear it, just like an SR flip-flop.
Finally, the schmitt trigger mode can be used to create an inverter gate that is able to clean up a noisy input into a clean digital output.
Applications
Taking a quick look around the internet will yield countless projects and circuit diagrams of what has been done with this versatile chip. In my opinion, 555-timer-circuits.com is one of the best for getting new ideas and learning, since it has 54 projects with good documentation. Some of these include a servo motor tester, rain alarm, traffic light system, and even a mock police siren.
Construction
To begin, the project's creator, acerlaguinto7, gathered some necessary materials, including some black illustration board, three aluminum cans, an actual NE555 timer IC, and some solder/glue sticks. He then drew pencil lines on the board at a 36.5x scale, which makes the giant timer 484 times larger!
Next, he sketched on the name, TI logo, and part information as well as the top notch and then cut and shaped it.
Adding Pins
Companies don't make DIP-8 packages that are this large, so adding pins would be a challenge to source and/or make. Conveniently, aluminum is conductive, so he was able to cut out eight giant pins and bent them into the correct shape.
Finally, the project's creator soldered on a single length of wire to each aluminum pin and attached the other end to the 555 timer, which is suspended in the middle of the box. Everything was hot-glued together to ensure rigidity.
Using It
Since this is still a normal NE555 timer, it can be used in place of any normal-sized IC. The author opted to demonstrate this by assembling an astable circuit that blinks an LED at a set rate. Notice how long the wiring has to be to connect the components.