Arduino Hacks

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Sentiment

Display Your City’s Emotional State With Illuminated Snow

February 5, 2015 by 8 Comments

[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” →

DJ Light Box Grooves To The Beat

February 4, 2015 by 2 Comments

During a Product Design class, [Oscar de la Hera] designed and built an LED light box that responds to music — and looks good doing it!

He carefully constructed the box out of Oak with a one-way mirror top, enclosing a 6 x 6 matrix array of NeoPixels. Behind the panel is an Arduino Uno which uses an MSGEQ7 chip and two audio jacks to take in an audio signal and create a light show. When the lights are off, it looks like a fancy little mirror — but when you turn on the music it becomes alive.

If you’re curious on how it was made, or if you want to make your own, there’s a full tutorial on how to make your own over at Instructables — and don’t forget to take a look at it in action after the break!

Continue reading “DJ Light Box Grooves To The Beat” →

How Fast Is Your Flash?

February 2, 2015 by 15 Comments

What’s cooler than learning about timers and interrupts on AVRs? Well, if you’re like [Matt], you can use that learning experience to build something useful – in this case, a timer for various camera flashes.

There are two ways to measure the speed of a flash. The first is the lag between when a button is pressed and when the flash goes off. As long as this is consistent, everything’s okay. The second type of speed is the pulse width. When looking at a xenon flash as time vs. brightness, they have a large spike at the beginning followed by a significant amount of decay. LED flashes are pretty much one cycle of a square wave.

To measure both types of flash speed, [Matt] used a $0.50 photodiode an a 3.5mm jack that ties into the flash remote. These bits are wired up to an Arduino, a little bit of fun work with timers and interrupts happens, and [Matt] learns how fast his flash is.

Automated Etch-a-Sketch Re-Produces Famous Artwork

February 2, 2015 by 25 Comments

Unless you’re some incredibly gifted individual with more dexterity than a fighter jet pilot, making anything on a Etch-a-Sketch is hard. So [Evan] decided to motorize it, and cheat a little bit.

She’s using an Arduino Uno to control two stepper motors that she has bound to the Etch-a-Sketch knobs using a short piece of rubber tube and Gorilla Glue. She 3D printed some custom motor mounts to allow the motors to be positioned directly above the knobs, and a ULN2803 to switch the 12V required for the steppers.

After she had the hardware all setup, she coded a simple Python script to take in .PNGs and produce vector art to be sent through the Arduino. In case you’re wondering, an Etch-a-Sketch has approximately 550 x 370 pixels, or about 500 x 320 for the “safe zone”.

Due to the limitations of the Etch-a-Sketch, like its inability to stop writing, some images might require some editing before sending it off to your new Etch-a-Sketch printer.

Continue reading “Automated Etch-a-Sketch Re-Produces Famous Artwork” →

ArduinoCamera

A Single Pixel Digital Camera With Arduino

January 31, 2015 by 29 Comments

[Jordan] managed to cobble together his own version of a low resolution digital camera using just a few components. The image generated is pretty low resolution and is only in grey scale, but it’s pretty impressive what can be done with some basic hardware.

The heart of the camera is the image sensor. Most consumer digital cameras have tons of tiny receptors all jammed into the sensor. This allows for a larger resolution image, capturing more detail in a smaller space. Unfortunately this also usually means a higher price tag. [Jordan’s] sensor includes just a single pixel. The sensor is really just an infrared photodiode inside of a tube. The diode is connected to an analog input pin on an Arduino. The sensor can be pointed at an object, and the Arduino can sense the brightness of that one point.

In order to compile an actual image, [Jordan] needs to obtain readings of multiple points. Most cameras do this using the large array of pixels. Since [Jordan’s] camera only has a single pixel, he has to move it around and take each reading one at a time. To accomplish this, the Arduino is hooked up to two servo motors. This allows the sensor to be aimed horizontally and vertically. The Arduino slowly scans the sensor in a grid, taking readings along the way. A Processing application then takes each reading and compiles the final image.

Since this camera compiles an image so slowly, it sometimes has a problem with varying brightness. [Jordan] noticed this issue when clouds would pass over while he was taking an image. To fix this problem, he added an ambient light sensor. The Arduino can detect the amount of overall ambient light and then adjust each reading to compensate. He says it’s not perfect but the results are still an improvement. Maybe next time he can try it in color.

Cracking Weather Station Checksum

January 30, 2015 by 7 Comments

[BaronVonSchnowzer] is spinning up some home automation and settled on an inexpensive ambient temperature sensor which is sold to augment the data a home weather station collects. He found that the RF protocol had been reverse engineered and will use this information to harvest data from a sensor in each room. In true hacker fashion, he rolled his own advances out to the Internet so that others may benefit. Specifically, he reverse engineered the checksum used by the Ambient F007TH.

He got onto this track after trying out the Arduino sketch written to receive the sensor’s RF communications. One peculiar part of the code turned out to be a filter for corrupt messages as the protocol’s checksum hadn’t yet been worked out. Figuring out how the checksum byte owrks wasn’t an easy process. The adventure led him to dump 13k samples into a spreadsheet to see if sorting similar sets of 5-byte message and 1-byte checksum would shed some light on the situation. The rest of the story is some impressive pattern matching that led to the final algorithm. Now [BaronVonSchnowzer] and anyone else using these modules can filter out corrupt data in the most efficient way possible.

Kill Time Making Flappy Bird, Not Playing It

January 30, 2015 by 12 Comments

With all the Flappy Bird clones floating around in the ether after the game’s unexpected success, there are some that are better than others. And by better, we mean, hacked together from misc hardware. If you’ve got an Arduino on hand, then you’re half way to making your own:

The “Minimalist” Version

[aron.bordin] created his own Flappy Bird game with a short list of parts some of us likely have lying around on our bench. An Arduino loaded with the appropriate code is wired to a 16×16 LED matrix, which apparently displays the minimal amount of visual information you’d need to play the game. The only other parts required are a single pushbutton and resistor tethered on a breadboard to control your flapping. With the wire hookup laid out by convenient diagrams and the libraries required for the code all found on the same page, this is easily something one could bang out in an afternoon. If afterwards you still find yourself with more time to kill than you can stand to play Flappy Birds, there is always the option of fashioning a humorously-sized cell phone case to squeeze it all into… which we’d like to see.

The “Fancy” Version

If you want more resolution than solid colored LEDs, or you just have a fondness for the terrifying bird abstraction the game is known for, you can switch out the 16×16 matrix for a Nokia LCD screen. [Huy’s] rendition of this build over on Hackaday.io will deliver a “more detailed” graphic for the game, and is still roughly just as easy to assemble. Similarly, an Ardunio is loaded with the smarts required to generate the game, along with a single pushbutton tacked on for control. The code and the daunting (/sarcasm) two steps needed to wire the Arduino to the screen can be found on his project’s page.

If you must kill boredom playing Flappy Bird, there is no excuse not to do so on something you made yourself.

Continue reading “Kill Time Making Flappy Bird, Not Playing It” →