Arduino Hacks

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Video With Sensor Data Overlay Via Arduino Mega

November 11, 2015 by 17 Comments

If you haven’t been paying attention, big wheel trikes are a thing. There are motor driven versions as well as OG pedal pushing types . [Flux Axiom] is of the OG (you only get one link, now its on you) flavor and has written an instructable that shows how to achieve some nice looking on screen data that he syncs up with the video for a professional looking finished product which you can see in the video after the break.

[Flux Axiom] is using an Arduino Mega in his setup along with a cornucopia of sensors and all their data is being logged onto an SD card. All the code used in his setup is available in his GitHub repository. [Flux Axiom] was also nice enough to include the calibration process he used for the sensors which is also located in the GitHub download.

Sadly [Flux Axiom] uses freedom hating software for combining the video and data, Race Render 3 is his current solution and he is pleased with the results. Leave it in the comments if you have an open source solution for combining the video and data that we can offer him as a replacement.

Edit: Correct spelling of handle.

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The Simplest Smart Glasses Concept

November 10, 2015 by 76 Comments

Google Glass kind of came and went, leaving one significant addition to the English language. Even Google itself used the term “glasshole” for people who used the product in a creepy way. We can’t decide if wearing an obviously homemade set of glasses like the ones made by [Jordan Fung] are more creepy, give you more hacker cred, or just make you look like a Borg. Maybe some combination of all of those. While the cost and complexity of developing for Google Glass was certainly a barrier for hacking on that hardware, this project is just begging for you to build your own and run with the concept.

[Jordan’s] build, called Pedosa Glass, really is pretty respectable for a self-built set up. The Arduino Nano is a bit bulky, and the three push buttons take up some room, but it doesn’t kill the ability to mount them in a glasses form-factor. An FLCoS display lets you see the output of the software which [Jordan] is still developing. Right now features include a timer and a flashlight that uses the head-mounted white LED. Not much, we admit, but enough to prove out the hardware and the whole point would be to add software you wanted.

Admittedly, it isn’t exactly like Google Glass. Although both use FLCoS displays, Pedosa Glass uses a display meant for a camera viewfinder, so you don’t really see through it. Still, there might be some practical use for a little display mounted in your field of vision. The system will improve with a better CPU that is easier to connect to the network with sensors like an accelerometer — there’s plenty of room to iterate on this project. Then again, you do have an entire second ear piece to work with if you wanted to expand the system.

Check out the video demo after the break.

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Trivia Lock Box Spices Up Wedding Reception

November 9, 2015 by 19 Comments

Any hardware hacker will tell you, a significant other who embraces your passion is a keeper. [Nathan] found a keeper in [Jessica] – they even worked together on a hardware hack for their own wedding. The couple wanted an interactive element for their guests. Disposable cameras are getting a bit hard to find these days, so the solution was a trivia powered lock box designed and built by [Nathan] himself. Guests arrived at their tables to find locked boxes and cards with trivia questions about the couple. Only by answering the questions correctly would they unlock the box to access the prizes inside.

Each box consists of a Really Bare Bones Board, which is essentially an ATmega328 breakout board. The user interface consists of five tactile switches and a 16×2 character based LCD. The box is a clear Vaultz pencil box (Yes, the same brand Ahmed used for his clock). The final element is of course the locking mechanism. One of [Nathan’s] friends noticed that the Vaultz box latch was riveted in, and was spring loaded. It only took a bit of work to flip the latch from the outside to the inside. Cheap 9g micro servos from the far east pull the latch open with a string. The only thing we haven’t figured out is how [Nathan] closed the latches while they were inside the box. Obviously some black magic was involved! [Jessica] decorated the box with circuit traces created on her vinyl cutter.

On the eve of the big day, [Nathan] realized that his tactile switches were… not really switching. The superglue he had used to mount them had seeped into the switch body, freezing it solid. Nathan saved the project with a herculean effort of soldering 5 switches on each of 12 boxes the night before his own wedding.

What was in the box? Alka-Seltzer tablets. When added to vases filled with oil and water, the fizzy tablets turned the vases into mini lava lamps. The boxes also contained coins which were redeemable for Hawaiian Leis.

Click past the break to see the boxes in action on [Nathan] and [Jessica’s] big day and if you’re looking to build a fleet of hardware for your own wedding, take a look at the centerpieces [Bill Porter] created a couple of years ago.

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Code Craft – Embedding C++: Classes

November 6, 2015 by 62 Comments

For many embedded C developers the most predominate and questionable feature of C++ is the class. The concern is that classes are complex and therefore will introduce code bloat and increase runtimes in systems where timing is critical. Those concerns implicate C++ as not suitable for embedded systems. I’ll bravely assert up front that these concerns are unfounded.

When [Bjarne Stroustrup] created C++ he built it upon C to continue that language’s heritage of performance. Additionally, he added features in a way that if you don’t use them, you don’t pay for them.

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The Robot Light Switch

November 6, 2015 by 24 Comments

Automating your home is an awesome endeavor — but playing with mains AC can be risky business if you don’t know what you’re doing. So why not play it safe and make use of your light switch?

Admittedly, it wasn’t because [Tyler Bletsch] didn’t want to mess around with AC directly, but rather out of necessity. You see, he just moved into a new office and his “smart” air conditioner… doesn’t turn itself off at night.

There’s a remote control to set the target temperature, but the unit isn’t smart enough to turn off at night. Instead, there’s a physical wall switch so you can turn it off with your actual physical hands, like a barbarian.

Refusing to be a barbarian (and to stay at work late), he decided to simplify the problem by building a servo driven light switch plate. It’s not the prettiest — but it does the trick. Continue reading “The Robot Light Switch” →

Automatic Cat Feeder Dispenses Noms, Wants Cheezburger

November 5, 2015 by 24 Comments

[Domiflichi] likes his cats, but not the drudgery of feeding them. So, like any good engineer, this simple problem became his next project: building an automatic cat feeder. Based on an Arduino, his creation beeps to let the cats know that it is dinnertime, then dispenses food into a number of bowls. There are also buttons for manual control. This lets him give individual cats a separate feeding. Rounding out the feature set, a DS1307 RTC tracks the feeding times.

One of the most interesting parts of his build is the transfer from breadboard to protoboard. This usually involves taking apart a working version, then putting it back together and trying to figure out why it doesn’t work anymore. [Domiflichi]’s problem (detailed in a follow-up post) was figuring out how to program the real-time clock module to set the time, because it looses the time when you disconnect the power. Rather than use the Arduino to program the RTC,  he used the battery backup feature of the RTC chip, programming it on his computer and then soldering it onto the board. He went on to remove the backup battery after the chip was in place. That’s a solution that will no doubt have many readers waving their fingers disapprovingly, but it worked.

It may seem overly complicated, but his project is worth checking out to see how he approached some of the engineering challenges. The food hoppers themselves are off-the-shelf cereal dispensers. We’ve seen other designs bootstrap this mechanism with 3D printed augers.

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Magnetic Levitation With Arduino

November 2, 2015 by 7 Comments

Getting a magnetic field to balance on another magnetic field is about as easy as balancing a bowling ball on the tip of an ink pen. With a little help from an Arduino mega, however, [EmmaSong] was able to balance a high density neodymium magnet in midair. He pulled off this tricky project using a set of four coils he got off of Taobao (the Chinese version of eBay), a hall effect sensor, and a handful of current regulation ICs.

The coils can be made in house if necessary, with each winding getting about 800 turns of enameled wire. The rest of the circuit is straightforward. It appears he uses a potentiometer for a rough regulation of the current going to the coils, doing the fine tuning in the code which can be found here (.RAR direct download).

We’ve seen magnetic levitation here before, and this project adds to the list of successful techniques to accomplish this difficult project.

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