If you are even remotely interested in electronics, chances are the number ‘555’ is immediately recognizable. It is, after all, one of the most popular IC’s ever built, with billions of units sold to date. Designed way back in 1970 by Hans Camenzind, it is still widely available and frequently used for various applications. [Ken Shirriff] does a teardown and analysis of a 555 and gives us a look at the internal structure of this oldie.
A metal can package allowed him to just chop off the top and get access to the die, which was way safer and easier than to etch out the black epoxy of a DIP package. He starts by giving us a quick run down on how the chip works, showing us the two comparators, the output flip-flop and the capacitor discharge circuitry that make up most of the chip. He then puts the die under a metallurgical microscope, and starts identifying the various sections of the chip. Combining pictures of individual elements with cross-sectional diagrams, he identifies the construction of the transistors and resistors, the use of a current mirror to replace bulky resistors, and the differential pair that makes up the comparators.
He wraps it up by providing an interactive map of the die and the schematic, where you can click on various parts and the corresponding component is highlighted along with an explanation of what it does. There’s some interesting trivia about how a redesigned, improved version – the ZSCT1555 – couldn’t survive the popularity and success of the 555. He wraps it up with a useful list of notes and references. While de-capping blog posts are interesting on their own, [Ken] does a great job by giving us a detailed look at the internals.
Thanks [Vikas] for sending in this tip.
The Clapper™ is a miracle of the 1980s, turning lights and TVs on and off with the simple clap of the hands, and engraving itself into the collective human unconsciousness with a little jingle that implores – nay, commands – you to Clap On! and Clap Off! [Rutuvij] and [Ayush] bought a clap switch kit, but like so many kits, this one was impossible to understand; building the circuit was out of the question, let alone understanding the circuit. To help [Rutuvij] and [Ayush] out, [Rafale] made his own version of the circuit, and figured out a way to explain how the circuit works.
While not the most important component, the most obvious component inside a Clapper is a microphone. [Rafale] is using a small electret microphone connected to an amplifier block, in this case a single transistor.
The signal from the microphone is then sent to the part of the circuit that will turn a load on and off. For this, a bistable multivibrator was used, or as it’s called in the world of digital logic and Minecraft circuits, an S-R flip-flop. This flip-flop needs two inputs; one to store the value and another to erase the stored value. For that, it’s two more transistors. The first time the circuit senses a clap, it stores the value in the flip-flop. The next time a clap is sensed, the circuit is reset.
Output is as simple as a LED and a buzzer, but once you have that, connecting a relay is a piece of cake. That’s the complete circuit of a clapper using five transistors, something that just can’t be done with other builds centered around a 555 timer chip.
PS1 hombrew competition
The PlayStation Development Network is hosting a six-month long competition to develop homebrew games for the original PlayStation.We don’t get many homebrew games for old systems in our tip line, so if you’d like to show something off, send it in.
This is how you promote a kickstarter
[Andy] has been working on an SNES Ethernet adapter and he’s finally got it working. Basically, it’s an ATMega644 with a Wiznet adapter connected to the second controller port. The ATMega sends… something, probably not packets… to the SNES where it is decoded with the help of some 65816 assembly on a PowerPak development cartridge. Why is he doing this? To keep track of a kickstarter project, of course.
What exactly is [Jeri] building?
[Jeri] put up an awesome tutorial going over the ins and outs of static and dynamic flip-flops. There’s a touch of historical commentary explaining why dynamic registers were used so much in the 70s and 80s before the industry switched over to static designs (transistors were big back then, and dynamic systems needed less chip area). At the end of her video, [Jeri] shows off a bucket-brigade sequencer of sort that goes through 15 unique patterns. We’re just left wondering what it’s for.
Finally, a camera for the Raspberry Pi
In case you weren’t aware, the camera board for the Raspberry Pi will be released sometime early next year. Not wanting to wait a whole month and a half, [Jouni] connected a LinkSprite JPEG serial camera to his Raspberry Pi. The whole thing actually works, but [Jouni] didn’t bother posting the code. Maybe we can encourage him to do so?
Blatant advertising? Yes, but fireballs
Nintendo gave [MikenGary] a Wii U and asked them to make a film inspired by 30 years of Nintendo lore and characters. They did an awesome job thanks in no small part to Hackaday boss man [Caleb](supplied the fire), writer [Ryan] (costume construction) and a bunch of people over at the Squidfoo hackerspace.
[M. Eric Carr] came up with an interesting build for the 555 contest earlier this year, and we’re pretty sure that it would have kicked the winner of the complex category off the throne if it were completed. Although it’s a few months late, we’re happy to feature at least part of his 555-based computer on Hack A Day.
Continue reading “Building a computer out of 555 chips”
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.
Continue reading “Beginner concepts: 555 push button toggle”