Posts with «capacitive touch» label

A capacitive touch Jankó keyboard

If you have even a passing familiarity with how to play a piano, you know that there are a bunch of long white keys, with a lesser number of black keys in a nearly-universal arrangement. On the other hand, like the standard and much lesser-known Dvorak keyboard for typing, there are alternatives. One such alternative is the Jankó keyboard, which Ben Bradley decided to reconstruct for the Moog Werkstatt using a capacitive touch sensor setup.

His new instrument, which as of his write-up only had 13 keys connected, was constructed for the 2017 Moog Hackathon at Georgia Tech. It uses an Arduino Mega for control along with four MPR121 capacitive touch breakout boards, and as seen in the video below, can be played quite well after only one day of practice!

You can find more details on his build, including its Arduino code, on the Freeside Atlanta website and check out its feature on Hackaday here.

(Photo: Nathan Burnham)

Capacitive Christmas Organ with Living Lenses of Slappable Light

We’ve seen capacitive touch organs manifest in pumpkin form. Though they are a neat idea, there’s something about groping a bunch of gourds that stirs a feeling of mild discomfort every time I play one. [mcreed] probably felt the same way and thus created this light-up Jello organ, so he can jiggle-slap Christmas carols, removing any sense of doubt that touching food to play music is weird…

This take on the capacitive tone producing instrument makes clever use of the transparent properties of Jello as well as its trademark wiggling. [mcreed] fills several small mold forms with festively colored strawberry and lime mix. One end of a wire connection is submerged in the liquid of each cup before it has a chance to solidify along with a bright LED. Once chilled and hardened, the gelatinous mass acts as a giant light emitting contact pad. An Arduino is the micro-controller used for the brain, assigning each Jello shape with a corresponding note. By holding onto a grounding wire and completing the acting circuit, one can play songs on the Jello by poking, spanking, or grazing the mounds.

Though I’m not entirely sure if the video is Jello propaganda or not, the idea is applaudable. I prompt anyone to come up with a more absurd item to use for a capacitive organ (zucchinis have already been done).


Filed under: Arduino Hacks, musical hacks

Pantry Light Demo

The pantry light is installed and working perfectly: I'll post code and circuit details eventually, not much to it though.

1-Day Project: Pantry Light

We have two pantries in our flat, one of which could use some light.

There's an outlet in there, but a simple solution won't do: I have more circuitry and time on my hands than I can handle, and the least I can do is make an over-complicated pantry light.

Parts lying around to use:

  • AC-DC converter blocks with screw-terminals outputting 12V at 2A. I have a bunch of these-- came with the LED strips.
  • A length of white LED strip.
  • Lots of TIP-120-style MOSFETs, intended for a second light suit. It's fun to have a lot of high power switches around.
  • Spare Arduino-compatible boards, including the "StripDuino" by "Tinkeract.com," here I quote the names since links go nowhere.
The idea is simple-- rest your hand on the large strip on the door sill as you scan the pantry contents. The light will turn on if you tap the strip, or it will fade if you leave your hand on it.

This design solves the problem uniquely with:

  1. Very large switch surface,
  2. Variable brightness by holding the switch,
  3. Indirect lighting from compact, dense LED strip tucked out of view.
I have a hardware sketch working in terms of the key elements of the controlling Arduino system:
  • Capacitive touch sensing works between pins D5 and D6 with a 1M resistor
  • Touch surface works: aluminum foil with soldered wire plus a layer of hot glue and tape.
  • PWM works with the MOSFET to control the LED strip nicely, with the board's 3.3V logic.
For the light strip at full power, I measure 240.8 mA at 11.85 V, so 2.85 W of power. This is not much but it scales proportionally to the length of the strip.

To do:

  1. Capture the working circuit in an Eagle schematic.
  2. Build a looping sketch with the tap/hold fading behavior.
More to come...

Droplet and StackAR bring physical interface to virtual experiences, communicate through light (hands-on)

Light-based communication seems to wind throughout the MIT Media Lab -- it is a universal language, after all, since many devices output light, be it with a dedicated LED or a standard LCD, and have the capacity to view and interpret it. One such device, coined Droplet, essentially redirects light from one source to another, while also serving as a physical interface for tablet-based tasks. Rob Hemsley, a research assistant at the Media Lab, was on hand to demonstrate two of his projects. Droplet is a compact self-contained module with an integrated RGB LED, a photodiode and a CR1216 lithium coin battery -- which provides roughly one day of power in the gadget's current early prototype status. Today's demo used a computer-connected HDTV and a capacitive-touch-enabled tablet. Using the TV to pull up a custom Google Calendar module, Hemsley held the Droplet up to a defined area on the display, which then output a series of colors, transmitting data to the module. Then, that data was pushed to a tablet after placing the Droplet on the display, pulling up the same calendar appointment and providing a physical interface for adjusting the date and time, which is retained in the cloud and the module itself, which also outputs pulsing light as it counts down to the appointment time.

StackAR, the second project, functions in much the same way, but instead of outputting a countdown indicator, it displays schematics for a LilyPad Arduino when placed on the tablet, identifying connectors based on a pre-selected program. The capacitive display can recognize orientation, letting you drop the controller in any position throughout the surface, then outputting a map to match. Like the Droplet, StackAR can also recognize light input, even letting you program the Arduino directly from the tablet by outputting light, effectively simplifying the interface creation process even further. You can also add software control to the board, which will work in conjunction with the hardware, bringing universal control interfaces to the otherwise space-limited Arduino. Both projects appear to have incredible potential, but they're clearly not ready for production just yet. For now, you can get a better feel for Droplet and StackAR in our hands-on video just past the break.

Continue reading Droplet and StackAR bring physical interface to virtual experiences, communicate through light (hands-on)

Droplet and StackAR bring physical interface to virtual experiences, communicate through light (hands-on) originally appeared on Engadget on Tue, 24 Apr 2012 15:03:00 EST. Please see our terms for use of feeds.

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