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214 Articles

How Hot Is Your Faucet? What Color Is The Water?

November 6, 2016 by 26 Comments

How hot is the water coming out of your tap? Knowing that the water in their apartment gets “crazy hot,” redditor [AEvans28] opted to whip up a visual water temperature display to warn them off when things get a bit spicy.

This neat little device is sequestered away inside an Altoids mint tin — an oft-used, multi-purpose case for makers. Inside sits an ATtiny85 microcontroller  — re-calibrated using an Arduino UNO to a more household temperature scale ranging from dark blue to flashing red — with additional room for a switch, while the 10k ohm NTC thermristor and RGB LED are functionally strapped to the kitchen faucet using electrical tape. The setup is responsive and clearly shows how quickly [AEvans28]’s water heats up.

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Navigation Thing: Four Days, Three Problems, And Fake Piezos

October 20, 2016 by 13 Comments

The “Navigation Thing“ was designed and built by [Jan Mrázek] as part of a night game activity for high school students during week-long seminar. A night-time path through a forest had stations with simple tasks, and the Navigation Thing used GPS, digital compass, a beeper, and a ring of RGB LEDs to provide a bit of “Wow factor” while guiding a group of students from one station to the next. The devices had a clear design direction:

“I wanted to build a device which a participant would find, insert batteries, and follow the beeping to find the next stop. Imagine the strong feeling of straying in the middle of the night in an unknown terrain far away from civilization trusting only a beeping thing you found. That was the feeling I wanted to achieve.”

The Navigation Things (there are six in total) guide users to fixed waypoints with GPS, a digital compass, and a ring of WS2812 LEDs — but the primary means of feedback to the user is a beeping that gets faster as you approach the destination. [Jan] had only four days to make all six units, which was doable. But as most of us know, delivering on a tight deadline is often less about doing the work you know about, and more about effectively handling the unexpected obstacles that inevitably pop up in the process.

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RGB LEDs: How To Master Gamma And Hue For Perfect Brightness

August 23, 2016 by 26 Comments

You would think that there’s nothing to know about RGB LEDs: just buy a (strip of) WS2812s with integrated 24-bit RGB drivers and start shuffling in your data. If you just want to make some shinies, and you don’t care about any sort of accurate color reproduction or consistent brightness, you’re all set.

But if you want to display video, encode data in colors, or just make some pretty art, you might want to think a little bit harder about those RGB values that you’re pushing down the wires. Any LED responds (almost) linearly to pulse-width modulation (PWM), putting out twice as much light when it’s on for twice as long, but the human eye is dramatically nonlinear. You might already know this from the one-LED case, but are you doing it right when you combine red, green, and blue?

It turns out that even getting a color-fade “right” is very tricky. Surprisingly, there’s been new science done on color perception in the last twenty years, even though both eyes and colors have been around approximately forever. In this shorty, I’ll work through just enough to get things 95% right: making yellows, magentas, and cyans about as bright as reds, greens, and blues. In the end, I’ll provide pointers to getting the last 5% right if you really want to geek out. If you’re ready to take your RGB blinkies to the next level, read on!

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Shark With Frickin’ LED Tells People Not To Bother You

January 1, 2016 by 5 Comments

Everybody is busy these days, but sometimes it’s hard to tell. What with teleconferences being conducted over tiny Bluetooth headphones and Skype meetings where we seem to be dozing in front of the monitor, we’ve lost some of the visual cues that used to advertise our availability. So why not help your colleagues to know when to give you space with this shark themed WiFi-enabled meeting light?

Why a shark and not a mutated intemperate sea bass? Only [falldeaf] can answer that. But the particulars of the build are well-documented and pretty straightforward. A Photon runs the show, looking for an Outlook VFB file to parse. An RGB LED is used to change the color of the translucent 3D printed shark based on whether you’re in a meeting, about to step into one, or free. The case is 3D printed as well, although [falldeaf] farmed the prints out to a commercial printing outfit because of the size and intricacy of the parts. He did fabricate a nice looking wood base for the light, though.

There are plenty of ways to tell people to buzz off, but this is a pretty slick solution. For those in open floor plan workspaces, something like this IoT traffic light for you and your cube-mates might be in order.

Color Sonification Could Be Key To Rainbow Connection

December 28, 2015 by 2 Comments

Have you seen any loud sweaters this holiday season? Now there is a way to quantify their vibrancy and actually hear them at the same time. Cornell engineering students [Mengcheng Qi] and [Ryan Land] focused on the sonification of color and translated the visible spectrum into audible sounds.

They originally planned to use pixel samples from an OV7670 camera module, but weren’t able to extract any useful color data from it. We prefer their Plan B anyway, which was to use CdS photo resistors and the plastic color filters used for photography in red, blue, and green. The varying intensity of light falling on the photo resistors creates different patterns according to the voltage levels. The actual sound generation was done with FM sound synthesis.

There wasn’t a lot of natural sound variation between different RGB values, so in order to make it more fun, they created different instruments which play different patterns at variable speeds and pitch according to the colors. In addition to the audio feedback, the RGB values are displayed in real-time on a small TFT. Below those are dynamic bar graphs that show the voltages of each color.

Check out the demo after the break; they walk through the project and try it out on different things to hear their colors.

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Video From Audio And Pure Data

October 11, 2015 by 12 Comments

Although graphical programming languages have been around for ages, they haven’t really seen much use outside of an educational setting. One of the few counterexamples of this is Pure Data, and Max MSP, visual programming languages that make music and video development as easy as dropping a few boxes down and drawing lines between them.

A few years ago, [Thomas] and [Danny] developed a very cool Pure Data audio-visual presentation. The program they developed only generated graphics, but though clever coding they were able to generate a few audio signals from whatever video was coming out of their computer. The project is called TVestroy, and it’s one of the coolest audio-visual presentations you’ll ever see.

The entire program is presented on three large screens and nine CRT televisions. With some extremely clever code and a black box of electronics, the video becomes the audio. Check it out below.

Although this is a relatively old build, [Thomas] thought it would be a good idea to revisit the project now. He’s open sourced most of the Pure Data files, and everything can be downloaded on the project page.

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Philips Lamp Upgrade

Increasing The Brightness Of A Philips LivingColors Lamp

June 12, 2015 by 6 Comments

[Martin] recently purchased a Philips LivingColors lamp. It’s a commercial product that basically acts as mood lighting with the ability to change to many different colors. [Martin] was disappointed with the brightness of his off-the-shelf lamp. Rather than spend a few hundred dollars to purchase more lamps, he decided to modify the one he already had.

[Martin] started by removing the front cover of his lamp. He found that there were four bright LEDs inside. Two red, one green, and one blue. [Martin] soldered one wire to the driver of each LED. These wires then connected to four different N-channel MOSFET transistors on a piece of protoboard.

After hooking up his RIGOL oscilloscope, [Martin] was able to see that each LED was driven with a pulse width modulated signal. All he had to do was connect a simple non-addressable RGB LED strip and a power source to his new driver board. Now the lamp can control the LED strip along with the internal LEDs. This greatly extends the brightness of the lamp with minimal modifications to the commercial product. Be sure to check out the video below for a complete walk through. Continue reading “Increasing The Brightness Of A Philips LivingColors Lamp” →