Electronic ColorChord Turns Color Into Sound

[Dr. Cockroach] has delighted us again with another of his circuits on cardboard. He calls it steampunk inspired, and while we guess we can see what he’s getting at, it’s more like a sweet example of artful dead bug construction. He calls it the ColorChord. Point its photo cells at a color and it’ll play a tone or a combination of tones specific to that color.

Three 555-centric boards use thumbtacks as connection points which he solders to, the same technique he used for his cardboard computer. They provide simple tones for red, green, and blue and a mix for any other color. However, he found that the tones weren’t distinguishable enough for similar colors like a bright sun yellow and a reddish yellow. So he ended up pulsing them using master oscillator, master-slave flip-flop, and sequencer circuits, all done dead bug style.

We’re not sure how practical it is but the various pulsed tones remind us of the B space movies of the 1950s and 60s. And as for the look of it, well it’s just plain fun to look at. Hear and see it for yourself in the video below.

And if you want to see some dead bug circuitry as high art then check out this awesome LED ring, this sculptural nixie clock, and perhaps the most wondrous of all, The Clock.

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555 Ways to Speed Control A DC Motor

The 555 timer IC is a handful of active components all baked into one beautifully useful 8 pin package. Originally designed for timing purposes, they became ubiquitous parts that can achieve almost anything. In this case, they’re being used to create a  basic PWM motor controller.

The trick is to set the 555 up in astable mode, and use diodes and a potentiometer in the charge/discharge loop. By hanging a diode off either side of a potentiometer, leading to the charge and discharge pins, and connecting the center lug to the main capacitor, you can vary the resistance seen by the capacitor during charge and discharge. By making charging take longer, you increase the pulse width, and by making discharge take longer, you reduce the pulse width. The actual frequency itself is determined largely by the capacitor and total resistance of the potentiometer itself.

This is a very old-school way to generate a PWM signal, which could be used to vary intensity of a light or make noise on a buzzer. However, in this case, the output of the 555 is connected to a MOSFET which is used to vary the speed of a computer fan motor.

It’s an excellent way to learn about both PWM motor control and the use of 555 timers, all with a very low parts cost and readily available components. We’ve seen such setups before, used as easy-to-build dimmer switches, too.

NES Controller Slider-Based Light Theremin

Having never use a 555 before, [lonesoulsurfer] decided that his first foray into the world’s most popular and versatile IC would be to use a 555 to make beautiful chiptunes. For that, we commend him. He found [Dean Segovis]’ Slidersynth light-based Theremin and got to work building his own version it and stuffing it into a (knockoff!) NES controller.

For the uninitiated, a Theremin is a touch-less synthesizer that uses human capacitance and a pair of antennae to control oscillation and amplitude. In a light-based Theremin such as this one, the oscillation is controlled by the intensity of photons from a white LED and their interaction with a light-dependent resistor, also known as a photocell or ‘squiggly resistor’.

The oscillations themselves are created by wiring up the 555 as an astable oscillator, and the pitch is controlled with a potentiometer mounted on the back. It has a small built-in speaker, but [lonesoulsurfer] replaced the B button with a 3.5 mm audio jack so he can plug it into a powered speaker and really rock out. We’ve got his demo tape queued up after the break.

We love pocket instruments around here. If you prefer brass and woodwinds, this pocket woodwind MIDI controller just might draw your lips into an O.

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Learning The 555 From The Inside

One way to understand how the 555 timer works and how to use it is by learning what the pins mean and what to connect to them. A far more enjoyable, and arguably a more useful way to learn is by looking at what’s going on inside during each of its modes of operation. [Dejan Nedelkovski] has put together just such a video where he walks through how the 555 timer IC works from the inside.

We especially like how he immediately removes the fear factor by first showing a schematic with all the individual components but then grouping them into what they make up: two comparators, a voltage divider, a flip-flop, a discharge transistor, and an output stage. Having lifted the internals to a higher level, he then walks through examples, with external components attached, for each of the three operating modes: bistable, monostable and astable. If you’re already familiar with the 555 then you’ll enjoy the trip down memory lane. If you’re not familiar with it, then you soon will be. Check out his video below.

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Home Decorating with Tiny Arcade Cabinets

Thanks to the general miniaturization of electronics, the wide availability of cheap color LCD screens, and the fact that licensing decades old arcade games is something of a free-for-all, we can now purchase miniature clones of classic arcade cabinets for about $20 USD. In theory you could play these things, but given they’re less than 4 inches in height they end up being more of a desk novelty than anything. Especially since it seems like most of the effort went into making the cabinet itself; a classic example of “form over function”.

Unfortunately, if you want to buy these little arcade cabinets to use as decoration for your office or game room, they aren’t particularly well suited to the task. The “demo” mode where the game plays itself doesn’t last for very long, and even if it did, the game would chew through batteries at an alarming rate. [Travis] decided to tackle both issues head on by powering his Tiny Arcades over USB and locking them into demo mode.

The stock power for the Tiny Arcade comes from three AAA batteries, or 4.5 V. This made it easy enough to run over  5 V USB, and a four port USB charger is used to provide power to multiple machines at once. Forcing the game to stay in demo mode wasn’t much harder: a 555 timer was used to “push” the demo button with a frequency of every 10 seconds or so to keep the game up and running. A simple timer circuit was put together in the classic “dead bug” style, and sealed up with liquid rubber so it would play nice with the insides of the Tiny Arcade.

Since his little machines wouldn’t need their stock power switches anymore, [Travis] rewired the speaker lead through it. So now the machine stays on and in demo mode as long as it’s plugged into USB power, and you can flip the switch on the back to turn off the sounds. Perfect for sitting up on a shelf or the corner of your desk.

Usability issues not withstanding, there’s a pretty big (no pun intended) following for micro sized arcade cabinets. We’ve seen projects ranging from modding a Game Boy Advance to even tinier scratch builds.

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The Tiniest Of 555 Pianos

The 555 timer is one of that special club of integrated circuits that has achieved silicon immortality. Despite its advanced age and having had its functionality replicated and superceded in almost every way, it remains in production and is still extremely popular because it’s simply so useful. If you are of A Certain Age a 555 might well have been the first integrated circuit you touched, and in turn there is a very good chance that your project with it would have been a simple electric organ.

If you’d like to relive that project, perhaps [Alexander Ryzhkov] has the answer with his 555 piano. It’s an entry in our coin cell challenge, and thus uses a CMOS low voltage 555 rather than the power-hungry original, but it’s every bit the classic 555 oscillator with a switchable resistor ladder you know and love.

Physically the piano is a tiny PCB with surface-mount components and physical buttons rather than the stylus organs of yore, but as you can see in the video below the break it remains playable. We said it was tiny, but some might also use tinny.

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Upgrading A USB Soldering Iron!

Seeing the popularity of the TS-100 soldering iron, GitHub user [ole00] found himself desirous of a few of its features, but was put off by its lack of a power supply. What is a hacker to do? Find a cheaper option, and hack it into awesomeness.

[ole00] stumbled across the inexpensive ZD-20U and — despite a handful (sorry!) of issues — saw potential: it’s compact, lightweight, and powered via a USB power cable. Wanting to use as much of the ZD-20U’s original board as possible, the modifications were restricted to a few trace cuts and component swaps. The major change was swapping out the 555 timer IC controlling the iron with am ATtiny13a MCU to give it a bit more control.

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