Posts | Comments

Planet Arduino

Archive for the ‘Holiday Hacks’ Category

Hackaday readers have certainly seen more than a few persistence of vision (POV) displays at this point, which usually take the form of a spinning LED array which needs to run up to a certain speed before the message becomes visible. The idea is that the LEDs rapidly blink out a part of the overall image, and when they get spinning fast enough your brain stitches the image together into something legible. It’s a fairly simple effect to pull off, but can look pretty neat if well executed.

But [Andy Doswell] has recently taken an interesting alternate approach to this common technique. Rather than an array of LEDs that spin or rock back and forth in front of the viewer, his version of the display doesn’t move at all. Instead it has the viewer do the work, truly making it the “Chad” of POV displays. As the viewer moves in front of the array, either on foot or in a vehicle, they’ll receive the appropriate Yuletide greeting.

In a blog post, [Andy] gives some high level details on the build. Made up of an Arduino, eight LEDs, and the appropriate current limiting resistors on a scrap piece of perfboard; the display is stuck on his window frame so anyone passing by the house can see it.

On the software side, the code is really an exercise in minimalism. The majority of the file is the static values for the LED states stored in an array, and the code simply loops through the array using PORTD to set the states of all eight digital pins at once. The simplicity of the code is another advantage of having the meatbag human viewer figure out the appropriate movement speed on their own.

This isn’t the only POV display we’ve seen with an interesting “hook” recently, proving there’s still room for innovation with the technology. A POV display that fits into a pen is certainly a solid piece of engineering, and there’s little debate the Dr Strange-style spellcaster is one of the coolest things anyone has ever seen. And don’t forget Dog-POV which estimates speed of travel by persisting different images.

[Thanks to Ian for the tip.]

There’s not much time left now. If you’re going to put something together to give the youngsters some night terrors in exchange for all that sweet candy, you better do it quick. This late to the game you might not have time to do anything too elaborate, but luckily we’ve come across a few quick Halloween hacks that can get you some pretty cool effects even if it’s only a few hours before the big night.

As a perfect example, these LED “blinking eyes” were created by [Will Moser]. Using nothing more exotic than some bare LEDs, an Arduino, and a cardboard box, these little gadgets can quickly and easily be deployed in your windows or bushes to produce an unsettling effect after the sun goes down. Thanks to the pseudorandom number generator in the Arduino code, the “eyes” even have a bit of variability to them, which helps sell the idea that your Halloween visitors are being watched by proper creatures of the night.

The hardware side of this project is very simple. [Will] takes a container such as a small cardboard box and cuts two holes in it to serve as the eyes. He notes that containers which are white or reflective on the inside work best. You’ll want to get a little artistic here and come up with a few different shaped sets of eyes, which is demonstrated in the video after the break. Inside each box goes a colored LED, wired back to the Arduino.

For the software, [Will] is using a floating analog pin as a source of random noise, and from there comes up with how often each LED will blink on and off, and for how long. Both the hardware and software sides of this project are perfect for beginners, so it might be a good way to get the Little Hackers involved in the festivities this year; if you’re the type of person who enjoys replicating small humans in addition to creeping them out.

LEDs seem to be the hacker’s decoration of choice come Halloween, from wearable LED eyes to remote controlled illuminated pumpkins.

For all the hustle and bustle of the holiday season, people still find ways to make time for their passions. In the lead up to Christmas, [Edwin Mol] and a few co-workers built themselves an LED Christmas tree that adds a maker’s touch to any festive decor.

Before going too far, they cut out a cardboard mock-up of the tree. This an easy step to skip, but it can save headaches later! Once happy with the prototype, they printed off the design stencils and cut the chunks of clear acrylic using power tools — you don’t need a laser cutter to produce good stuff — and drilled dozens of holes in the plastic to mount LEDs, and run wires.

A Raspberry Pi 3 and Arduino Uno make this in league with some pretty smart Christmas trees. MAX6968 5.5V constant-current LED driver chips and MOFSETs round out the control circuit. During the build, the central LED column provided a significant challenge — how often do you build a custom jig to solder LEDs? That done, it’s time for a good ol’-fashioned assembly montage! The final product can cycle through several different lighting animations in a rainbow of colours — perfect for a festive build.

Even though Christmas has just passed, your holiday hacks are still flooding in! While you wait for us to push those out the metaphorical door, check out some of our other favorites like this massive pixel display, a free-formed LED tree, and a Raspberry Pi gingerbread house.


Filed under: Arduino Hacks, Holiday Hacks

There’s something about impressing strangers on the Internet that brings out the best in us. Honestly, we wouldn’t be able to run this site otherwise. A perfect example of this phenomenon is the annual Reddit Secret Santa, where users are challenged to come up with thoughtful gifts for somebody they’ve never even met before.

For his entry into this yearly demonstration of creativity, [Harrison Pace] wanted to do something that showcased his improving electronic skills while also providing something entertaining to the recipient. So he came up with a box of goodies which is unlocked by the successful completion of a built-in trivia game tailored around their interests. If this is how he treats strangers, we can’t wait to see what he does for his friends.

Hardware packed into the lid so the box itself remains empty.

There’s quite a bit of hardware hidden under the hood of this bedazzled gift box. The primary functions of the box are handled by an Arduino Nano; which runs the trivia game and provides user interaction via a 16×2 LCD, three push buttons, and a buzzer. Once the trivia game is complete, a servo is used to unlock the box and allow the recipient access to the physical gifts.

But that’s not the only trick this box has hidden inside. Once the main trivia game is complete, a ESP8266 kicks into action and advertises an access point the user can connect to. This starts the second level of challenges and gifts, which includes a code breaking challenge and gifted software licenses.

The project wasn’t all smooth sailing though. [Harrison] admits that his skills are still developing, and there were a few lessons learned during this project he is unlikely to forget in the future. Some Magic Smoke managed to escape when he connected his 5V Arduino directly to the 3.3V ESP8266, but at least it was a fairly cheap mistake and he had spares on hand to get the project completed anyway.

This project is reminiscent of reverse geocache boxes which only open when moved to a certain location, but the trivia aspect makes it perfect even for those of us who don’t want to put pants on just to receive our Internet gifts.


Filed under: Arduino Hacks, Holiday Hacks

Christmas light displays winking and flashing in sync to music are a surefire way to rack up views on YouTube and annoy your neighbours. Inspired by one such video, [Akshay James] set up his own display and catalogued the process in this handy tutorial to get you started on your own for the next holiday season.

[James], using the digital audio workstation Studio One, took the MIDI data for the song ‘Carol of the Bells’ and used that as the light controller data for the project’s Arduino brain. Studio One sends out the song’s MIDI data, handled via the Hairless MIDI to serial bridge, to the Arduino which in turn sets the corresponding bit to on or off. That gets passed along to three 74HC595 shift registers — and their three respective relay boards — which finally trigger the relay for the string of lights.

From there, it’s a matter of wiring up the Arduino shift register boards, relays, and connecting the lights. Oh, and be sure to mount a speaker outdoors so passers-by can enjoy the music:

Be sure to set up a secondary power source for the relays, as drawing the power from the Arduino is likely to cause big problems. If your preferred digital audio workstation doesn’t have a virtual MIDI instrument, [James] used loopMIDI for the desired effect. He has also provided the code he used to save you some trouble if you’re building this during an invariably hectic holiday season.

Of course, you could always plug your lights into an IoT power bar and have fun that way.


Filed under: Arduino Hacks, Holiday Hacks

The WS2812 is an amazing piece of technology. 30 years ago, high brightness LEDs didn’t even exist yet. Now, you can score RGB LEDs that even take all the hard work out of controlling and addressing them! But as ever, we can do better.

Riffing on the ever popular Adafruit NeoPixel library, [Harm] created the WS2812FX library. The library has a whole laundry list of effects to run on your blinkenlights – from the exciting Hyper Sparkle to the calming Breathe inspired by Apple devices. The fantastic thing about this library is that it can greatly shorten development time of your garden-variety blinkables – hook up your WS2812s, pick your effect, and you’re done.

[Harm]’s gone and done the hard yards, porting this to a bevy of platforms – testing it on the Arduino Nano, Uno, Micro and ESP8266. As a proof of concept, they’ve also put together a great demonstration of the software – building some cute and stylish Christmas decorations from wood, aluminium, and hacked up Christmas light housings. Combining it with an ESP8266 & an app, the effects can be controlled from a smartphone over WiFi. The assembly video on YouTube shows the build process, using screws and nails to create an attractive frame using aluminium sheet.

This project is a great example of how libraries and modern hardware allow us to stand on the shoulders of giants. It’s quicker than ever to build amazingly capable projects with more LEDs than ever. Over the years we’ve seen plenty great WS2812 projects, like this sunrise alarm clock or this portable rave staff.
As always, blink hard, or go home. Video after the break.


Filed under: Arduino Hacks, Holiday Hacks, led hacks

[Conor] wired up his 3D-printed coffin doorbell to an array of RGB LEDs, a screaming speaker, and a spinning skull on a cordless screw driver to make a “quick” Halloween scare. Along the way, he included half of the Adafruit module catalog, a relay circuit board, and ESP8266 WiFi module, a Banana Pi, and more Arduinos of varying shapes and sizes than you could shake a stick at.

Our head spins, not unlike [Conor]’s screaming skull, just reading through this Rube Goldbergy arrangement. (We’re sure that’s half the fun for the builder!) Smoke ’em if ya got ’em!

Start with the RGB LEDs; rather than control them directly, [Conor] connected them to a WiFi-enabled strip controller. Great, now he can control the strip over the airwaves. But the control protocol was closed, so he spent a week learning Wireshark to sniff the network data, and then wrote a Bash script to send the relevant UDP packets to turn on the lights. But that was not fancy-schmancy enough, so [Conor] re-wrote the script in Go.

Yes, that’s right — a Go routine on a Banana Pi sends out custom UDP packets over WiFi to a WiFi-to-LED-driver bridge. To make lights blink. Wait until you see the skull.

spooky_eye_animThe plastic skull has Neopixels in each ping-pong ball eye, controlled by an Arduino Nano and battery taped to the skull’s head. The skull is cemented to a driver bit that’s chucked in a cordless drill. A relay board and another Arduino make it trigger for 10 seconds at a time when the doorbell rings. Finally (wait for it!) an Arduino connected to the doorbell gives the signal, and sets a wire high that all the other Arduini and the Banana Pi are connected to.

Gentle Hackaday reader, now is not the time for “I could do that with a 555 and some chewing gum.” Now is the time to revel in the sheer hackery of it all. Because Halloween’s over, and we’re sure that [Conor] has unplugged all of the breadboards and Arduini and put them to use in his next project. And now he knows a thing or two about sniffing UDP packets.


Filed under: Arduino Hacks, Holiday Hacks, misc hacks

Planning to make that carved a pumpkin last past Halloween night? Forget the tealight or LED candle—here’s an easy, no-solder project that will make it extra special. By default, this jack-o-lantern looks like it has a flickering flame, but get close enough to it and it goes crazy with color.

All you need is an LED matrix, a Rainbowduino to drive it, a PIR motion sensor to trigger the random colors, and a power source. [Alpha Charlie] kept the electronics from becoming pumpkin-flavored with some plastic bags. Since he used the PIR as the jack-o-lantern’s nose, there is a bit of plastic behind it to keep moisture from interfering.

[Alpha Charlie]’s build instructions are quite detailed, which makes this project even simpler if you’ve never used a PIR before. There are lots of ways you could build on this project to make it your own, like using trick-or-treater motion to trigger screams or spooky sounds, or add more sensors to make it more interactive. Watch it react after the break.

If you have nothing else at all to do between now and trick-or-treat time, you could bust out the soldering iron and recreate this 70-LED matrix jack-o-lantern. Blinkenlights too safe for your tastes? Fire-breather it is, then.


Filed under: Arduino Hacks, Holiday Hacks

Halloween is just around the corner, and the spooky themed tips are just starting to roll in. If you’re looking to one-up the basic store-bought decorations, and maybe teach your kid the basics of an Arduino while you’re at it — why not build a Peek-A-Boo Ghost!

Using an Arduino, two servo motors and an ultrasonic distance sensor it’s pretty easy to make this cute little ghost that covers its eyes when no one is around. They’re using cardboard for the ghost, but if you have access to a laser cutter at your hackerspace, you could make it a lot more robust using MDF or plywood.

When the ultrasonic distance sensor senses someone coming towards it, it’ll trigger the arms to move — though it’d be easy to add a small speaker element too and get some spooky music going as well!

For even more spooky hacks, check out our coverage of last year’s Halloween Night at Pololu! Including impatient severed fingers, a robotic exorcism baby, and not to mention some stabby silhouettes for your windows!


Filed under: Arduino Hacks, Holiday Hacks

“It’s only software!” A sentence that strikes terror in the heart of an embedded systems software developer. That sentence is often uttered when the software person finds a bug in the hardware and others assume it’s going to be easier for fix in software rather than spin a new hardware revision. No wonder software is always late.

[Clint Stevenson] is his own hardware and software guy, as are most of us. He wanted to use the less expensive HC-SR04 ultrasonic rangefinder in a prototype. Longer term he wanted to have the choice of either a Parallax PING or MaxBotix ultrasonic sensor for their better performance outdoors. His hardware hack of the SR04 made this a software problem which he also managed to solve!

[Clint] was working with the Arduino library, based on the Parallax PING, which uses a single pin for trigger and echo. The HC-SR04 uses separate pins. Originally he modified the Arduino library to accept the two pin approach. But with his long term goal in mind, he also modified the HC-SR04 sensor by removing the on-board pull-up resistor and adding a new one on the connector side to combine the signals. That gave him an SR04 that worked with the single-pin based library.

We’ve seen Parallax PING projects for sensing water depth and to generate music. These could be hacked to use the HC-SR04 using [Clint’s] techniques.

[Arduino and HC-SR04 photo from http://www.blaxlab.com/%5D


Filed under: Arduino Hacks, Holiday Hacks, software hacks


  • Newsletter

    Sign up for the PlanetArduino Newsletter, which delivers the most popular articles via e-mail to your inbox every week. Just fill in the information below and submit.

  • Like Us on Facebook