Arduino Hacks

3036 Articles

Talking Tactile 3D Prints

November 8, 2014 by 7 Comments

Cell biology professor [Mike] has created a way for blind students to decipher microscope slides using 3D prints and the magic of capacitive sensing. His write-up focuses on a slide showing the anaphase stage of mitosis in whitefish blastula, a popular choice for studying cell division. When a student touches a certain area of the print, the capacitive sensor triggers audio playback to tell them what they’re feeling.

[Mike] started by turning a 2D image of a cell into a 3D print. To do this, he made the image black and white, and then inverted the colors so that the 3D print’s topography will correspond correctly. The talking part is handled by an Arduino Duemilanove and a Spikenzie voice shield. The latter has a somewhat limited amount of space, but is more than adequate for the audio labels [Mike] made, which are all less than three seconds long.

A hard copy of the 2D file comes in handy for making sure the cap sensors are in the right places. To make those, [Mike] cut up some floor protector pads and covered the sticky side with copper tape. These are held on the 2D image with double-sided tape. The 3D print sits on top, separated by more furniture pads at the corners. He labeled this scientific sandwich model with a 3D printed Braille label that reads ‘anaphase’. [Mike] has made the referenced STL file along with a few others available at the National Institutes of Health’s 3D print exchange site.

Using Router SoCs As WiFi Modules (Yet Again)

November 6, 2014 by 34 Comments

8-bit AVRs and 32-bit ARMs do one thing, and one thing well: controlling other electronics and sensors while sipping power. The Internet of Things is upon us and with that comes the need for connecting to WiFi networks. Already, a lot of chips are using repackaged System on Chips to provide an easy way to connect to WiFi, and the USR-WIFI232-T is the latest of the bunch. It’s yet another UART to WiFi bridge, and as [2XOD], it’s pretty easy to connect to an AVR.

The module in question can be had through the usual channels for about $11, shipped straight from China, and the only purpose of this device is to provide a bridge between a serial port and a wireless network. They’re not that powerful, and are only meant for simple tasks,

[2XOD] got his hands on one of these modules and tested them out. They’re actually somewhat interesting, with all the configuration happening over a webpage served from the device. Of course the standard AT commands are available for setting everything up, just like the ESP8266.

With a month of testing, [2XOD] has found this to be a very reliable device, logging temperatures every minute for two weeks. There’s also a breakout board available to make connection easy, and depending on what project you’re building, these could be a reasonable stand-in for some other popular UART -> WiFi chips.

Undershield, DIY Arduino Battery Shield

Battery Shield Mounts Underneath The Arduino

November 6, 2014 by 26 Comments

So, what do you do when your Arduino project needs to operate in a remote area or as a portable device? There are LiPo battery shields available, and although they may work well, recharging requires access to a USB port. You can also go the 9v battery route plugged into the on-board regulator of the Arduino but the low mAh rating of a 9v won’t allow your project to stay running for very long. [AI] needed a quick-change battery option for his Arduino project and came up with what he is calling the AA Undershield.

As the name implies, AA sized batteries are used in the project, two of them actually. Yes, two AA batteries at 1.5v each would equal only 3 volts when connected in series. The Arduino needs 5v so [AI] decided to use a MAX756 DC-to-DC step-up regulator to maintain a steady stream of 5v. This article has some nice graphs showing the difference in performance between a 9v battery being stepped down to 5v verses two AA’s being bumped up to 5v.

The ‘under’ in Undershield comes from this shield being mounted underneath the Arduino, unlike every other shield on the planet. Doing so allows use of a standard 0.100″-spaced prototype PCB and is an easy DIY solution to that odd-sized space between the Arduino’s Digital 7 and 8 pins. The Arduino mounts to the Undershield via its normal mounting holes with the help of some aluminum stand offs.

[AI] did a great job documenting his build with schematics and lots of photos so that anyone that is interested in making one for themselves can do so with extreme ease.

Reinventing The Wheel Makes For A Better Wheel…

November 5, 2014 by 40 Comments

When robots take over the earth, it will be important that they maneuver across various types of terrain quickly and effectively. Bipedal motion is a tricky feat to accomplish for machines, so [Carter Hurd] decided, why not invent a better wheel? Even wheels can be improved, right?

Making excellent use of the prototyping capabilities of a 3D printer, [Carter] designed a set of bulb-shaped mechanisms which act effectively to drive themselves around on a smooth surface. The bulb is split radially into a series of wedge slices which can articulate outward, transforming the robot into something of a spiky razor-beast, able to tear through piles of fall leaves or wakes of loose sand. In order to unfurl itself however, the shaft driving the central mounting plate of the wedges has to fight the robot’s own weight. To solves this, [Carter] modified his design so that the rest of the wedges would unfold around the one supporting the load, the wheels would then rotate to shift the weight, allowing the last piece to extend.

[Carter] shows a proof of concept from earlier this year, explaining his hinge design which stretches a tendon-like connector in order to tension the wedges in one state or the other. Since then it looks like his transforming wheel has evolved a bit. You can get a better view of his robot in action here :

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The Tale Of Two Wearable Game Boys

November 3, 2014 by 9 Comments

We’re well past the time when Halloween costume submissions stop hitting the tip line, but like ever year we’re expecting a few to trickle in until at least Thanksgiving. Remember, kids: documentation is the worst part of any project.

[Troy] sent us a link to his wearable Game Boy costume. It’s exactly what you think it is: an old-school brick Game Boy that [Troy] wore around to a few parties last weekend. This one has a twist, though. There’s a laptop in there, making this Game Boy playable.

The build started off as a large cardboard box [Troy] covered with a scaled-up image of everyone’s favorite use of AA batteries. The D-pad and buttons were printed out at a local hackerspace, secured to a piece of plywood, and connected to an Arduino Due. The screen, in all its green and black glory, was taken from an old netbook. It was a widescreen display, but with a bezel around the display the only way to tell it’s not original is from the backlight.

Loaded up with Pokemon Blue, the large-scale Game Boy works like it should, enthralling guests at wherever [Troy] ended up last Friday. It also looks like a rather quick build, and something we could easily put together when we remember it next October 30th.

[Troy] wasn’t the only person with this idea. A few hours before he sent in a link to his wearable Game Boy costume, [Shawn] sent in his completely unrelated but extremely similar project. It’s a wearable brick Game Boy, a bit bigger, playing Tetris instead of Pokemon.

[Shawn]’s build uses a cardboard box overlaid with a printout of a scaled-up Game Boy. Again, a laptop serves as the emulator and screen, input is handled by a ‘duino clone, and the buttons are slightly similar, but made out of cardboard.

Both are brilliant builds, adding a huge Game Boy to next year’s list of possible Halloween costume ideas. Videos of both below.

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Push Button, Receive Candy (or Death)

October 30, 2014 by 14 Comments

Will you be handing out candy on Halloween? Maybe you have a party to attend or kids to take around the neighborhood and can’t be home to answer the bell. You don’t want to be The Dark House With No Candy, ’cause that’s a good way to get TP’d. We’re not exactly sure what [Ben]’s catalyst was aside from trying to avoid tempting would-be thieves with an unattended bowl on the porch. Whatever the reason, we’re happy to present Candy or Death, his gamified candy (or death)-dispensing machine.

Okay, so it only dispenses candy for now. [Ben] hasn’t quite worked the kinks out of his death ray. He designed it to sit behind a porch-facing window so it can’t be messed with. All trick-or-treaters can do is push the button and take the candy. It’s built around a cereal dispenser that’s modified to be cranked by a piece of round rod driven with a NEMA-17 stepper motor and an Arduino Uno with a motor shield. The candy slides down a length of aluminium rain gutter into a plastic stacking bin, and the whole thing is built into a nice wood frame.

A few adjustments were necessary to keep it from jamming. The dispenser’s hopper uses rubber blades to govern the flow, and he ended up removing a few and trimming the others. [Ben] has an album up of all his build pics and put his code on the gits. Stick around to see videos of the machine from the front and rear.

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Wireless Warning Sign

Bluetooth-Enabled Danger Sign For Lab

October 29, 2014 by 16 Comments

[A Raymond] had some free time at work, and decided to spend it on creating a wireless warning sign. According to his blog profile, he is a PhD student in Applied Physics. His lab utilizes a high-powered laser system. His job is to use said system, but only after it’s brought online by faculty scientists. The status of the laser system is changed by a manual switchbox that controls the warning signs wired around the lab entrances. Unfortunately, if you were in the upstairs office, you only knew this after running downstairs to check. [A Raymond’s] admitted laziness finally got the better of him – he wanted a sign that displayed the laser’s status from the comfort of the office. He had an old sign he could use, but he wanted a way for it to communicate with the switchbox downstairs. After some thought, he decided Bluetooth was the way to go, using a pair of BlueSMiRF Bluetooth modules from Sparkfun and Arduino Uno R3’s.

He constructed a metal box that intercepted the cable from the main switchbox, mounting one BlueSMiRF and Uno into it. Upon learning that the switchbox sends 12V AC signals over three individual status wires, he half-wave rectified the wires and divided their voltages so that the Uno wouldn’t fry. Instead, it determined which status wire that had active voltage. and sent a “g(reen)”, “y(ellow)”, or “r(ed)” signal continuously via Bluetooth. On the receiving end, [A Raymond] gutted the sign and mounted the other BlueSMiRF and Uno into it along with some green, yellow, and red LEDs. The LEDs light up in response to the corresponding Bluetooth signal.

The result is a warning sign that is always up-to-date with the switchbox’s status. We’ve covered projects using Bluetooth before, from plush birds to cameras– [A Raymond’s] wireless sign is in good company. He notes that it’s “missing” a high pitched whining noise when the “Danger” lights are on. If he decides to add an accompanying (annoying) sound, he couldn’t go wrong with something like this. Regardless, we’re sure [A Raymond] is happy that he no longer has to go back and forth between floors before he can use the laser.