Conductive filament means printable sensors

The 3D printer world has the creation of plastic trinkets pretty much down pat. The next step, obviously, is the creation of multi-material models, whether they be made of two different colors of plastic, or completely different materials entirely. A few folks from the University of Warwick and GKN Aerospace in Bristol, UK have come up with a way of putting electronic sensors directly into 3D printed objects.

These new sensors rely on a conductive filament custom-made for this study. So far, the researchers have created flex sensors, capacitive buttons, and a ‘smart’ mug that can sense how much water is contained within.

To produce their ‘carbomorph’ filament, the researchers stirred regular old carbon black to a sample of polycaprolactone dissolved in a solvent. After shaking well, the mixture was laid out on a piece of glass for an hour resulting in a thin film that could then be rolled into a 3mm filament. While this is a great way of producing small quantities of carbomorph filament, we’re sure a few Hackaday readers can come up with an easier way of rolling their own conductive filament. Send us a link if you’ve figured out a better way.

Tip ‘o the hat to [Evan] for this one

Bananaphone lets you use fruit and other things as switches

We’re used to [Sprite_TM] rolling out his own hacks hot on the heels of new concepts. Now we’re glad to see that [Jeff Ledger] is doing the same thing here. He was inspired by a Kickstarter project which vows to let you use fruit, clay, and a number of other common (but weird for this use) substances to interface with electronic projects. The mess you see above is the Bananaphone, a synthesizer played with touch sensitive bananas. Think of them as keys on a piano.

The interface works by measuring R/C decay. Each banana is connected to its own input pin on the Propeller board. The capacitance of the bananas rise when you touch them, and this results in a longer R/C decay measurement. Calibrate the target decay period, and you’ve got a reliable capacitive touch sensor which also happens to be delicious. Check out the results which [Jeff] achieves in the video after the break.

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Replicating the fancy touch sensor that uses anything

[Sprite_tm], a name many of you will recognize from these pages, has wasted no time in replicating the latest cool thing in a much simpler fashion. En Garde is a touch sensor that can detect up to 32 different points of contact on… whatever you use as the surface.  He couldn’t sit idly by and let the Disney funded one from yesterday keep the spot light. As you can see in the video, it works pretty well. If he didn’t tell you that his can only detect up to 32 points as opposed to the 200 of the other, you probably wouldn’t even notice the difference.  Of course, [Sprite_tm] also shares how you could easily beef his up to be even more precise. You can also download his source code an schematics from his site and give it a try yourself.

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Reaching out to a touch screen with a microcontroller

We love capacitive touch screens. They’re much more robust than resistive touch screens and if the UI is programmed well they produce a great user experience. But getting your electronics project to interact with one is a bit tough. [RobB] has been experimenting in that area, and managed to build a simple touchscreen actuator for microcontroller use.

In the video after the break you can see his proof of concept. He’s using an Arduino to enter the number 2 on an Android  iOS calculator app once every second. It doesn’t take much to pull off this trick, [RopB] just taped a piece of tin foil to the screen and connected it to the Arduino with a jumper wire. The pin is left floating until a screen tap is needed, at which point it is pulled to ground.

A custom app operating at slow speeds could use this as an input technique. Two pieces of foil (one acting as clock, the other data) would provide a rudimentary serial transfer system.

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Touch-based wirless RGB lamp control

[Alex] built an add-on board for his TI launchpad that lets him use it as a wireless controller for an RGB lamp (translated). As you can see above, the board has a pair of female pin-headers which make it easy to install or remove the board. This way you can use it for other projects without any hassle.

The board itself doesn’t have any buttons. Instead, [Alex] etched a two-sided PCB, including pads for use as capacitive touch sensors. Here we only see the underside of the board, which hosts four RGB LED modules. These give feedback by showing the levels which are about to be set for each color. In the clip after the break you’ll get a good look at the touch sensors. There are two that act like buttons, scrolling through each color channel, and sending the updated values to the lamp via a wireless module mounted on that same side. There are also four pads which act as a slider. We didn’t see any code but apparently this uses one of TI’s touch sensor libraries.

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NES controller uses capacitive touch instead of buttons

Here’s one way to really keep the component count low. [David] developed an NES controller that doesn’t use any buttons. The copper clad has been milled to provide a pad which registers a button push based on capacitance. The board has a SIL header at the top, making it easy to plug into the Arduino board that reads the inputs.

[David] had trouble getting the Arduino pin read functions to respond fast enough for he NES console’s expectations. He ended up using commands to access the ATmega’s peripherals directly in order to achieve the target timing. Speaking of, he did his own sniffing of the communication scheme using a logic analyzer. The results of that work, as well as the board files and code are available at the site linked above. And there’s a demo of the controller used to play Super Mario Bros. in the clip after the break.

This is actually a tangential project using a PCB mill which he’s developing through Kickstarter. This certainly shows that the mills works as designed.  Continue reading “NES controller uses capacitive touch instead of buttons”

Capacitive touch sensor shield for the TI Launchpad

Texas Instruments just released a product they call the Capacitive Touch Boosterpack which is basically a touch-sensitive shield for the Launchpad. The video after the break shows an unboxing and demonstration of the product which TI is launching with a $4.30 limited-time price tag. The red PCB itself has a capacitive touch button in the center, surrounded by a touch-scroll wheel, which is centered in a proximity senor that takes up the rest of the board. There are also nine LEDs which look like they’re soldered on the underside of the board, through routed holes that mount them flush with the top surface. The pack also comes with a new MSP430 microcontroller, the G2452, which has 8 KB of flash memory and takes care of calibrating, reading, and processing signals from the board thanks to the software package that goes along with the add-on kit.

Looks quite nice. There’s a heck of a lot of information in the documentation for this hardware. We do wish it was a bit easier to find board layout information, but we’re sure it’s there somewhere.

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