An Arduino Programmable Load

February 24, 2014 by Brian Benchoff 31 Comments

Having a big block of hot to dump current into is a very useful thing to have if you’re testing batteries, power supplies, high power LEDs, electroplating, or any thing else that would normally require a huge resistor. [Jakub] found himself in need of an electronic load, and instead of a transistor and a pot, decided to make something more automatic: a programmable load built around an Arduino shield.

The idea behind this load is pretty simple: connect a device to a FET and shunt resistor to measure current. Drive the gate of the FET with an op-amp that maintains either constant current or constant voltage. Control everything with a DAC, and you have a programmable load controlled by an Arduino.

With such a small form factor, getting rid of all that heat was bound to be a problem. For this, [Jakub] is using a 50×50 mm BGA style heat sink with a 5V fan. If it’s good enough for a big CPU, it should be able to handle dumping 70 Watts into a FET. There’s also a conservative application of thermal paste and a very small thermistor underneath the FET that’s able to be read by the Arduino. It might slowly heat up your room, but it’s not going to catch fire.

With the Arduino sketches [Jakub] wrote for his load he was able to characterize a pair of Idea batteries and figure out how much charge a three-year-old recyclable battery had. It’s a great piece of work, and if [Jakub] is willing to go through the hassle of a Kickstarter, it would make a fine crowdfunded product.

SoundCube: A Companion Cube That Can Talk

February 23, 2014 by Marsh 2 Comments

sound_companionCube

The Enrichment Center likely disapproves of the SoundCube: a portal music box in the form of a Portal Companion Cube. [Andreas] finished this project a couple of years ago, but we’re glad he’s finally had time to give a rundown on the details at his blog.

The build is primarily a modified speaker box cube—constructed out of what appears to be MDF—with four Alpine SXE-1725S speakers placed at the center of the middle faces. The faces were routed out to resembled the Companion Cube, while the electronics mount and the speaker grills were 3d printed. Inside is a homemade amplifier built around an Arduino Mega, with a TDA7560 quad bridge amplifier, a TDA7318 audio processor, a Belkin bluetooth receiver, and a 3.5″ touchscreen for volume control and for input selections.

Two 12v 7.2Ah lead-acid batteries keep the cube functional for an entire weekend of partying, but probably add a few pounds to the already hefty MDF construction. Check out [Andreas’s] blog for more pictures and his GitHub for all the necessary code.

Meltinator 9000 Fuses Glass By Degrees

February 21, 2014 by Kristina Panos 11 Comments

kiln [Richard]’s wife scored an Evenheat glass-fusing kiln, but the 20-year-old temperature controller was broken. He could have simply ordered a replacement controller, but that kind of problem solving doesn’t get you on Hack a Day. His wife wanted more control over the kiln and he convinced her that building their own was the way to go. Thus, the Meltinator 9000 was born.

[Richard]’s design uses an Arduino Uno and an Adafruit display shield, protoshield, and thermocouple reader board. He built a simple relay driver with a resistor, BJT, and a diode and connected it to pin 13 and its built-in indicator. To [Richard]’s delight, all of this fit in the original enclosure.

[Richard]’s software provides 25 fusing schedules with ten steps apiece. Each step has a target temperature, rate of temperature change, and a hold time which can be increased on the fly. He ran a test program that heated the kiln to 1500°F at a rate of 2550°F/hour. He then cooled it to 500°F at a rate of 1000°F/hour, which took longer than he thought. The good news is that the kiln is well-insulated! [Richard] has the software available on his GitHub.

Don’t have a glass kiln? Prefer to control beer-related temperatures? You could always hack your stove in the name of homebrewing.

Open Bitcoin ATM

February 20, 2014 by Marsh 30 Comments

openBitcoinAtm

If there’s one thing Bitcoins can benefit from, it’s easier accessibility for first-time users. The process can be a bit daunting if you’re new to cryptocurrency, but [mayosmith] is developing an open Bitcoin ATM to help get coins in the hands of the masses. There are already some Bitcoin dispensers out there. The Lamassu is around 5k a pop, and then there’s always the option of low-tech Condom Vending Machine conversions.

[mayosmith’s] build is still in the proof-of-concept phase, but has some powerful functionality underway. The box is made from acrylic with a front plate of 12″x12″ aluminum sheet metal, held on by 2 aluminum angles and some bolts. Slots were carved out of the aluminum sheet for the thermal printer and for bill acceptor—the comments identify it as an Apex 7000. Inside is an Arduino with an SD Shield attached. Dollars inserted into the acceptor trigger the Arduino to spit out a previously-generated QR code for some coins via the thermal printer, though all values are pre-determined at the time of creation and stored sequentially on the SD card. Stick around for a quick video below, and check out the official page for more information: http://openbitcoinatm.org

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Real Life Flappy Bird In A Box

February 20, 2014 by James Hobson 14 Comments

Flappy bird this, flappy bird that, we’re really not too sure how a clone of the original helicopter game became so darn popular. Anyway, [Fawn Qiu] — founder of MakeAnything — decided to hop on the bandwagon and made this awesome physical version of Flappy Bird!

She threw it together at the Tribeca Hacks Hackathon, and it uses an Arduino, two servo motors, a reed switch and some magnets. She was inspired by the original Mario in a Box game and this is a great example of her project MakeAnything, which is a technology project community which helps foster the new culture of STEM (Science Technology Engineering Mathematics) for kids and adults alike, in the United States. They believe that “with the right tool and instructions, we can all make anything and everything!”.

Stick around for the following video where [Fawn] takes it to the streets to let random strangers try their hand at the now iconic game!

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Mobile Hackerspace Status Indicator

February 18, 2014 by James Hobson 16 Comments

HACKERSPACE LIGHT

Cruising around town, not sure what to do — oh hey look, someone is at the hackerspace! Introducing the Mobile Spacestate Indicator!

During our Hackerspacing in Europe tour, we had the pleasure of visiting ACKspace in Heerlen, the Netherlands. And like many hackerspaces, they have an online status indicator letting members and non-members alike know if the space is open. [Vicarious], the gentleman who kindly picked us up from the train station, has just finished off an awesome modification to his car. Using an Arduino Uno and a Raspberry Pi, he has created a mobile indicator of his hackerspace’s status.

The Raspberry Pi automatically tethers to his phone and checks the status of the hackerspace online. It then sends the data to the Arduino Uno which controls a small strip of RGB LEDs. He’s cleverly hidden all of this inside his center console, and it looks awesome!

To see more of ACKspace’s cool projects, check out their wiki!

Arduino Gets Fowl With Flappy Bit

February 18, 2014 by Adam Fabio 7 Comments

flappy-bit

We have to swallow our pride and hand it to [Dan200]. He may have finally found an application that everyone can agree is a perfect fit for Arduino. Flappy Bit is [Dan’s] Arduino Uno based Flappy Bird clone. [Dan] is a software guy at heart, but he’s taken a peck at electronics of late. Flappy Bit was just a fun side project for him to learn how to program the Arduino. The hardware consists of an 8×8 LED matrix, current limiting resistors, and a single button.

[Dan’s] implementation isn’t 100% faithful to the iOS/Android original. Rather than simply parrot Flappy Bird, he changed it up a bit. The user presses and holds the button to climb, and releases it to descend. This seems to make the game a bit more forgiving. We also won’t be missing all the lovely sound effects from Flappy Bird. While there is less flapping in Flappy Bit, it does make us more nostalgic for those tabletop LCD/LED games we played in the 80’s and can’t stop crowing about today.

[Dan] has released the full source code to the project (Pastebin link), and there is more information available on his reddit thread. Give flappy bit a try. You won’t egret it!

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