With only a week left until Valentine’s day, [Henry] needed to think on his feet. He wanted to build something for his girlfriend but with limited time, he needed to work with what he had available. After scrounging up some parts and a bit of CAD work, he ended up with a nice animated LED Valentine heart.
[Henry] had a bunch of WS2812 LEDs left over from an older project. These surface mount LED’s are very cool. They come in a small form factor and include red, green, and blue LEDs all in a single package. On top of that, they have a built-in control circuit which makes each LED individually addressable. It’s similar to the LED strips we’ve seen in the past, only now the control circuit is built right into the LED.
Starting with the LEDs, [Henry] decided to build a large animated heart. Being a stickler for details, he worked out the perfect LED placement by beginning his design with three concentric heart shapes. The hearts were plotted in Excel and were then scaled until he ended up with something he liked. This final design showed where to place each LED.
The next step was to design the PCB in Altium Designer. [Henry’s] design is two-sided with large copper planes on either side. He opted to make good use of the extra copper surface by etching a custom design into the back with his girlfriend’s name. He included a space for the ATMega48 chip which would be running the animations. Finally, he sent the design off to a fab house and managed to get it back 48 hours later.
After soldering all of the components in place, [Henry] programmed up a few animations for the LEDs. He also built a custom frame to house the PCB. The frame includes a white screen that diffuses and softens the light from the LEDs. The final product looks great and is sure to win any geek’s heart. Continue reading “Animated LED Valentine Heart”
[Hunter] wanted to do something a bit more interesting for his holiday lights display last year. Rather than just animated lights, he wanted something that was driven by data. In this case, his display was based on the mood of people in his city. We’ve seen a very similar project in the past, but this one has a few notable differences.
The display runs off of an Arduino. [Hunter] is using an Ethernet shield to connect the Arduino to the Internet. It then monitors all of the latest tweets from users within a 15 mile radius of his area. The tweets are then forwarded to the Alchemy Sentiment API for analysis. The API uses various algorithms and detection methods to identify the overall sentiment within a body of text. [Hunter] is using it to determine the general mood indicated by the text of a given tweet.
Next [Hunter] needed a way to somehow display this information. He opted to use an LED strip. Since the range of sentiments is rather small, [Hunter] didn’t want to display the overall average sentiment. This value doesn’t change much over short periods of time, so it’s not very interesting to see. Instead, he plots the change made since the last sample. This results in a more obvious change to the LED display.
Another interesting thing to note about this project is that [Hunter] is using the snow in his yard to diffuse the light from the LEDs. He’s actually buried the strip under a layer of snow. This has the result of hiding the electronics, but blurring the light enough so you can’t see the individual LEDs. The effect is rather nice, and it’s something different to add to your holiday lights display. Be sure to check out the video below for a demonstration. Continue reading “Display Your City’s Emotional State with Illuminated Snow”
[Stacey] wanted a more interesting way to monitor events related to her Twitter account. What she ended up with is a beautiful animated heart light.
She started out by designing the enclosure. Having access to a laser cutter, she opted to make it out of thin plywood. [Stacey] used an online tool called BoxMaker to design the actual box. The tool is very simple to use. You simply plug in the dimensions of the box and it will provide you with a two dimensional template you can use with your laser cutter. The resulting plywood pieces fit together like a puzzle. The heart piece is made from frosted acrylic and was also cut by the laser.
To light up the heart, [Stacey] opted to use NeoPixels. These are like many of the RGB LED strips we’ve seen in the past, though the pixel density is higher than most. She cut up the LED strip into the appropriate sizes and glued them to a piece of plywood in a rough heart shape. She tested the lights during each step so she would know exactly when any errors were made.
[Stacey] opted to use a SparkCore to control the LEDs. This had the advantage of including WiFi connectivity out of the box. [Stacey] started with NeoPixel example programs, but quickly realized they all relied on the Delay function. This was a problem for her, because she needed to constantly watch for new Twitter events. She ended up having to write her own functions that relied on interrupts instead.
[Stacey] then wrote a Node.js script to monitor twitter and control the Spark. The script watches for specific events, such as one of [Stacey’s] tweets being re-tweeted, or a user unfollowing [Stacey]. The script then sends a message to the Spark to tell it which event just occurred. The Spark will then repeat the event until a new one occurs. Check out the demonstration video below. Continue reading “TweetHeart Shows You Some Love”
This schematic is all you need to build your own voltage converter. [Lutz] needed a converter that could boost 5 V to 30 V to power a string of LEDs. The solution was to use low cost ATtiny85 and some passive components to implement a boost converter.
This circuit follows the classic boost converter topology, using the ATtiny85 to control the switch. The 10 ohm resistor is fed back into the microcontroller’s ADC input, allowing it to sense the output voltage. By measuring the output voltage and adjusting the duty cycle accordingly, the circuit can regulate to a specified voltage setpoint.
A potentiometer is used to change the brightness of the LEDs. The software reads the potentiometer’s output voltage and adjusts the voltage output of the circuit accordingly. Higher voltages result in brighter LEDs.
Of course, there’s many other ways to implement a boost converter. Most practical designs will use a chip designed for this specific purpose. However, if you’re interested in rolling your own, the source and LTSpice simulation files are available.
Last year, [Ytai] went to Burning Man for the first time. He was a bit inexperienced, and lacked the lumens to make him visible on the Playa. This year, he made up for it by building an extra bright LED Jacket.
The jacket consists of 48 LEDs, at 150 lumens each. Each RGB LED module was placed on its own PCB, and controlled by the tiny PIC12F1571 microcontroller. This microcontroller was a great fit since it has three PWM channels (one for each color) and costs 50 cents. Firmware on the PIC allows the boards to be daisy-chained together to reduce wiring. This was done by using a protocol similar to the popular WS2811 LEDs.
Assembling 50 of the boards presented a challenge. This was addressed by using surface mount components, a solder stencil from OSH Stencils, an electric skillet, and a good amount of patience. The final cost of each module was about $3.
With 50 of the boards assembled, a two layer jacket was sewn up. The electronics were sandwiched between these two fabric layers, which gave the jacket a clean look. A wrist mounted controller allows the wearer to select different patterns.
For a full rundown of the jacket, check out the video after the break.
Continue reading “A Very Bright LED Jacket”
Burning man, the premier desert-based convention, is a vacation for some. [Sam], on the other hand, points out that he is there to get his hands dirty. This year, he (with a team of six) built a set of 20 interactive lotus flowers that light up in sync with a heartbeat.
[Sam]’s biofeedback circuit is able to sense up to two heartbeats per flower. When a person’s heartbeat is detected, a set of high-power LEDs light up from the base of the stem upwards towards the petals for an incredible illuminated display of biofeedback.
The lotus flowers themselves aren’t anything to scoff at, either. They range from 8 to 18 feet high and are made out of steel and rowlux plastic. The circuit boards are all custom-made as well, with every part chosen to be as affordable as possible. The whole installation is powered by a deep-cycle marine battery and a set of 6V batteries, which can run all of the electronics in the flowers for the entire night before needing a recharge.
Burning man is a great example of art meeting technology. For other examples, check out this 2010 pyrotechnic ball, or head there yourself next August! Be sure to check out the videos and the project’s code on the project site as well.
LED’s are fun. They are easily seen, not to hard to hook up, and produce a nice glow that can be gazed at for hours. Kids love them, so when [Jens] daughter was born, he knew that he wanted to create a device that would alternate colors depending on the object’s movement.
He utilized a mpu6050 accelerometer to detect changes in position, and wired together an Arduino Nano, a 9V battery, and a 12 LED neopixel ring from adafruit. Design requirements were jotted down beforehand ensuring that any child playing with the Hypno-Jellyfish would not be injured in any way. For example, anything that fits in a child’s mouth, will go in that child’s mouth; meaning that any materials used must be non-toxic, big enough not to be swallowed, and drool proof/water proof. The kids will pull, and throw, and drop the toy as well, so everything has to be of sturdy quality too. Epilepsy is also a concern when dealing with LED’s. But, [Jens] project hit the mark, making something that is kid-friendly while at the same time enjoyable for anyone else who likes color-changing lights.
Continue reading “Hypno-Jellyfish is Great for Kids (and Kids at Heart)”