An automatic color mixer, dispensing a mixture of red and yellow

The M5Stack Color Maker Can Mix Paint To Match Your Subject

October 11, 2021 by Robin Kearey 28 Comments

We’ve all learned in primary school art classes that blue and yellow make green, and that adding a little black to a color will make it darker. But what if you want to paint with a color that exactly matches something else? Usually, that requires a lot of trial and error (and paint), and the end result may not look the way you wanted after all.

To help aspiring artists, [Airpocket] made the M5Stack Color Maker. This is a device that reads out a color sensor and automatically mixes watercolor paint in the right proportions to match what it sensed. It dispenses drops of cyan, magenta, yellow and black paint (CMYK) into a small bowl, from which you can then apply it with a paintbrush.

The color sensor is similar in use to the color picker (or “dropper”) tool present in most graphics programs: simply point it at something that has the right color, and it will generate the correct values for you. It is based on an AMS TCS34725 color sensor, which is housed in a 3D-printed shell that also includes a white LED. The sensor outputs Red, Green and Blue (RGB) values, which are converted into the corresponding CMYK values by a Raspberry Pi Pico. A touch-sensitive screen allows the user to make adjustments before activating the paint pumps.

Those pumps are tube pumps, which have been specifically designed (and also 3D printed) to allow them to move tiny amounts of liquid while minimizing the pulsing motion typical with this type of pump. They are driven by stepper motors which are controlled by the Pi Pico.

Although many artists might prefer to mix their colors manually, the M5Stack makes mixing that exact shade of blue just that little bit easier. We can also imagine it might help those who are color blind and unable to clearly tell different colors apart. We’ve seen simple paint mixers for larger quantities of paint, and even robots that can do the actual painting for you. If you need a refresher on color theory, we’ve got you covered too.
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LED Matrix Hourglass Knows Which Way Is Up

October 8, 2021 by Donald Papp 6 Comments

[Fearless Night]’s slick dual hourglass doesn’t just simulate sand with LEDs, it also emulates the effects of gravity on those simulated particles and offers a few different mode options.

The unit uses an Arduino (with ATMEGA328P) and an MPU-6050 accelerometer breakout board to sense orientation and movement, and the rest is just a matter of software. Both the Arduino and the MPU-6050 board are readily available and not particularly expensive, and the LED matrix displays are just 8×8 arrays of red/green LEDs, each driven by a HT16K33 LED controller IC.

The enclosure and stand are both 3D-printed, and a PCB not only mounts the components but also serves as a top cover, with the silkscreen layer of the PCB making for some handy labels. It’s a clever way to make the PCB pull double-duty, which is a technique [Fearless Night] also used on their earlier optical theremin design.

Those looking to make one of their own will find all the design files and source code handily available from the project page. It might not be able to tell time in the classical sense, but seeing the hourglass displays react to the device’s orientation is a really neat effect.

Vintage TV play The Brady Bunch on loop using modern electronics

Groovy TV Gets A Very Brady Makeover

October 7, 2021 by Ryan Flowers 17 Comments

Here’s the story of an old Sharp TV, which was donated to [mandy] to be hacked. Just one look and you can see, very clearly, it plays old Brady Bunch tracks.

Upon inspection of the old television, [Aaron] and [mandy] found that the unit first hit the local Montgomery Ward in 1969. And what just momentous event played on televisions across North America in 1969? Well yes, the Apollo moon landing. And David Bowie’s Space Oddity. And Abbey Road. And Woodstock. But no, we’re talking about that other momentous event that would shape young minds for generations to come:

The pilot episode of The Brady Bunch.

Yes, The Brady Bunch, that campy TV show that first aired in 1969 and ended in 1974. It just so happens that [mandy]’s favorite TV show is The Brady Bunch, so when the bright orange Sharp TV came along, she knew what had to be done.

While the style of the television may be timeless, the internals weren’t. They were removed, and a new internal frame was built from a naturally occurring cellulose/lignin composite adorned in Brady Blue. Inspired by in-store advertising displays and billboards that play the same content on a loop, [mandy] and [Aaron] added an Eyoyo 7” monitor and an Aptek video player.

Leaving no question as to what era the TV came from, the revamped piece now plays about 50 of [mandy]’s favorite Brady clips on loop, all modified to be centered properly on the off-center screen. Groovy! To round out the experience and keep things mellow, the knobs were re-attached using Lego pieces, and are reportedly very satisfying to spin.

If you’ve got a thing for vintage hacks, you might like this Pi-powered NuTone home intercom or this vintage camera flash turned clock. And if you have any awesome hacks you think we’d like to see, be sure to send them on over to the Tip Line!

Flame-Spitting Dragon Head Heats Up Halloween

October 4, 2021 by Donald Papp 4 Comments

Halloween is looming, and [Jonathan Gleich] decided that an ideal centerpiece would be a flame-spitting dragon’s head. It started with an economical wall-mount dragon’s head, combined with a variety of off-the-shelf components to become something greater.

Dragon head with arc ignitor lit — Spark from high-voltage ignitor, right at the torch opening.

The fire comes from a kind of propane torch sold as a weed killer set, which looks a little like a miniature tiger torch. The flow of propane is limited by a regulator (which keeps the flame short and fixed), and controlled with a gas-rated 12 V solenoid valve. Ignition is done with the help of a spark igniter that fires up on demand, fed by a high-voltage ignition coil. The two combine at the Dragon’s mouth, where the flame originates, but the electrical components are otherwise isolated from the gas elements as much as possible.

The dragon head is made of acrylic, and if exposed to enough heat acrylic will first melt, then burn. To help avoid a meltdown, the dragon breathes fire only intermittently. [Jonathan] also gave the mouth area a heat-resistant barrier made from generous layers of flame-blocking mortar and sealants from the hardware store. The finishing touch comes in the form of bright red LEDs in the eyes, which give the head a bit more life.

Watch the ignitor in action and see the head spewing flames in the two short videos embedded below. The head should make for some good pictures come Halloween, and is a good example of how repurposing off-the-shelf items can sometimes be just what is needed for a project.

Interested in something smaller, but still fiery? Check out this pet fire-breathing dragon project for all your robotic animal companion needs. Continue reading “Flame-Spitting Dragon Head Heats Up Halloween” →

Automate Your Graffiti With The Graffomat!

September 30, 2021 by Jim Heaney 30 Comments

In Banksy’s book, Wall and Piece, there is a very interesting quote; “Imagine a city where graffiti wasn’t illegal, a city where everybody could draw whatever they liked…”. This sounds like it would be a very exciting city to live in, except for those of us who do not have an artistic bone in their body. Luckily, [Niklas Roy] has come up with the solution to this problem; the Graffomat, a spray can plotter.

The Graffomat is, in its creator’s own words, a “quick and dirty graffiti plotter.” It is constructed primarily from wood and driven by recycled cordless drills that pulls string pulleys to move the gantry. The Arduino Nano at the heart of the Graffomat can be controlled by sending coordinates over serial. This allows for the connection of an SD card reader to drip-feed the machine, or a computer to enable real-time local or over-the-internet control.

We are especially impressed with how [Niklas] handled positional tracking. The cordless drills were certainly not repeatable like a stepper motor, as to allow for open-loop control. Therefore, the position of the gantry and head needed to be actively tracked. To achieve this, the axes are covered with black and white striped encoder strips, that is then read by a pair of phototransistors as the machine moves along. These can then be paired with the homing switches in the top left corner to determine absolute position.

Graffomat is not the first automated graffiti machine we’ve covered. Read here about the robot that painted murals by climbing smokestacks in Estonia.

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The Most Important Device In The Universe on display at Modern Props

The Most Important Device In The Universe Is Powered By A 555 Timer

September 23, 2021 by Ryan Flowers 45 Comments

The Hackaday comments section has become infamous for a recurring theme that goes something like “I don’t know why they used an Arduino, they could have done it with a 555 timer!” If you’ve ever thought the same way, then this post is for you!

What is The Most Important Device In The Universe, then? It’s the Modern Props #195-290-1, a movie prop originally built in the 1970’s. It’s a product of the creative mind of [John Zabrucky] who founded Modern Props in 1977 to serve Sci-Fi television and movie productions that wanted to invent the future with their props. Known for their high quality and impeccable craftsmanship, Modern Props’ products were in demand until the day they closed the doors so that [John] could retire.

This particular piece is called The Most Important Device In The Universe due to its ubiquity in modern productions that we’ve all heard of: several Star Trek franchises, The Last Starfighter, Knight Rider, Airplane II, Austin Powers, and countless others. The next time you sit down to watch a Sci-Fi show, see if you can spot it! Be sure to check the video below the break to see several examples.

Nobody is sure what The Most Important Device does, aside from the fact that it has red lights that go back and forth. What we do know, thanks to a comment by the man who installed the electronics, [Gene Turnbow], is how it’s powered. [Gene] explained that 45w NPN power transistors drive the neon tubes through step up transformers. The transistors themselves are connected to a 74C4514 demultiplexer, which is itself driven by a 7493 binary counter. What’s the 7493 driven by? You guessed it: the venerable 555 Timer. And so it is that the 555 timer runs The Most Important Device In The Universe.

We did think that [Gene]’s final comment was rather indicative of how much things have changed since the prop was originally built. After explaining the device, he says “These days we would just use an Arduino to do the same job.” Indeed.

Don’t worry, 555 lovers. We’ve got you covered with this Vacuum Tube 555, and and the Trollduino, a 555 on an Arduino Shield. Thanks [Matt K] for the great tip. Don’t forget to submit your favorite hacks to our Tip Line!

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PCB Metro Maps Are A Gorgeous Labor Of Love

September 19, 2021 by Tom Nardi 21 Comments

Is your love of public transportation matched only by your passion for designing custom PCBs? If so, then you’re going to love these phenomenal transit maps created by [Chai Jia Xun]. Using the painstakingly refined principles outlined in his detailed write-up, he’s created versions for Tokyo, Singapore, and the comparatively spartan San Francisco Bay Area. All you need to make one up for your home town is an incredible amount of patience and dedication. No problem, right?

As [Xun] explains, the first part of creating one of these maps isn’t unlike generating a normal PCB. Just make a footprint for the stations, consult with Google Maps as to where they should be placed on the board, and then connect them all up with traces to stand in for the rail lines. A little silkscreen work, and you’re done.

Well…unless you want them to light up, anyway. To pull that off, [Xun] created a second PCB that places an LED behind each station hole drilled in the previous board. With a microcontroller and shift register, he’s able to selectively illuminate individual lines and run through different patterns. To combat light bleeding through the PCB, a CNC-cut piece of 3 mm MDF sits between the two boards to make sure each LED is only visible through the respective hole in the top surface.

You could call the map finished here as well, assuming you don’t mind all the stations lighting up white. If you want them to be different colors, you’ll need to insert some colored diffusers. [Xun] went through several different approaches here, but in the end, the idea that seemed to work best was to simply print out all the colored dots on a piece of transparency paper and use a second sheet of tracing paper to soften the light. Alignment here is critical, but once everything is dialed in, the results are quite impressive.

It’s quite a bit of work, and we haven’t even mentioned the fact that [Xun] had to modify the circuit when it came time to do the Tokyo map, as some MOSFETs had to be added into the mix for the microcontroller to reliably control 350+ LEDs. So there’s certainly no shame in simply buying one of them when they go on sale instead of trying to recreate it from scratch. Assuming you live in one of the cities he’s offering, anyway. Otherwise, you might want to take a look at our HackadayU class on KiCad and get yourself a comfortable chair.