Creating capacitive touch-sensitive buttons is easy these days; many microcontrollers have cap-sense hardware built-in. This will work for simple on/off control, but what if you want a linear, position-sensitive input, like you’d find on a computer touchpad or your smartphone screen? Not so easy — at least until now. Trill is a family of capacitive touch sensors you can add to your projects as a linear slider, a square touchpad, or by creating your own touch surface.
Trill was created by the same team that designed Bela, an embedded platform for low-latency interactive applications, especially with audio. The new trio of Trill sensors rely on capacitive sensing to track finger movement, and communicate over I2C with your microcontroller or development board of choice. The Trill I2C library targets Arduino and Bela, but should be easy to port to any I2C host.
The hardware and software are both open-source — or will be as the Kickstarter that launched this morning has already met its goal. The firmware for the Cypress CY8C20636A (PDF) controller that powers these sensors will be released CC-BY-NC-SA. But, starting with the controller itself sounds like a lot of work that Trill has already done for you, so let’s have a look at what we know so far, along with a healthy dose of speculation.
Continue reading “Trill: Easy Positional Touch Sensors For Your Projects”
We were wondering what [Circuitbeard] has been up to lately. Turns out he’s been building a mini pinball cabinet to add to his arcade of self-built games.
[Circuitbeard] was forced to break out of his Raspi comfort zone this time. We’re glad he did because this is one impressive build. Finding the pinball emulation community lacking for Linux, he turned to the LattePanda, a tiny Windows 10 SBC with a built-in Arduino Leonardo. This was really the perfect board because he needed to support multiple displays with a minimum of fuss. That Leonardo comes in handy for converting button presses to key presses inside the Visual Pinball emulator.
The 3mm laser-cut plywood cabinet was designed entirely in Inkscape and sized around the two screens: a genuine 7″ LattePanda display for the playfield, and a 5″ HDMI for the back glass. The main box holds the Lattepanda, two Pimoroni mini speakers, and a fan to keep the board cool.
There’s a lot to like about this little cabinet thanks to [Circuitbeard]’s fantastic attention to detail, which you can see for yourself in the slew of pictures. Look closer at the coin drop—it’s really an illuminated button with a custom graphic. If you want to have a go at emulating this emulator, all the code is up on GitHub. Tilt past the break to watch some modern pinball wizardry in action, and then check out his mini Outrun machine.
If pinball emulators don’t score any points with you, here’s one that’s all wood and rubber bands.
Continue reading “Tiny Pinball Emulator Is Hugely Impressive”
Are you the mutant savior? Are you prepared for the robot uprising of 2084? Have you accepted robotron into your life? The Church of Robotron is now conducting training, testing, and confession at the new window altar in downtown Portland.
The Church of Robotron is the
fake totally legit religion based on the classic arcade game prophecy Robotron 2084. In keeping with the church’s views on community outreach and missionary work, a Robotron altar has been installed at the Diode Gallery for electronic arts.
The altar consists of a system running Robotron 2084 with capacitive sensing controls built by DorkbotPDX’s own [Phillip Odom]. He’s using the same techniques featured in his capacitive sensing workshop, allowing the game to be played 24 hours a day. There are also monitors displaying the leaderboard and tenants of the Church of Robotron.
The Church of Robotron has also been showing up at Toorcamp for a few years now, with an even more spectacular altar that triggers physical events in response to game events. That’s a very cool use of MAME’s debugger, and a story worthy of its own Hackaday post.
Video of the altar below.
Continue reading “Repent! The Church Of Robotron Accepts All!”
The pen is mightier than the sword, but the IBM Model M keyboard, properly applied, can knock teeth in. There are a few more IBM keyboards even better suited to blunt force trauma – the extremely vintage beam spring keyboards made for terminals and desktop publishers. Being so very old, there’s no easy way to connect these keyboards to a modern system, so when [xwhatsit] wanted to make his work, he needed to build his own controller.
The beam spring keyboards use capacitive switches, and with 122 keys, the usual method of reading capacitance – putting a capacitor in an oscillator – would be far too slow to be of any use in a keyboard. There is another method of reading capacitance: measuring the current going through the capacitive switch. This can easily be accomplished with an LM339 comparator.
[xwhatsit]’s keyboard controller uses this capacitive sensing circuit to read the four rows of keys, with a few shift registers taking care of the columns. An ATMega32u2 is the brains of the outfit, running LUFA to translate the key presses to USB.
If you’re lucky enough to have one of these ancient keyboards, [xwhatsit] is selling a few over on the usual mechanical keyboard forums. There’s also a controller for the Model F keyboard using the same basic circuit. If you need one just drop him a line or grab the gerbers and roll your own.
Capacitive sensing libraries for the Arduino and just about every other microcontroller platform have been around for ages now, but if you’d like to put a slightly complex cap sense pad in a PCB without a lot of work, you’re kind of out of luck. Not only do you need a proper education in how capacitors work, but a custom cap sense pad also requires some advanced knowledge of your preferred PCB layout program.
The folks over at PatternAgents have just the solution for this problem. They created an Eagle library of touch widgets that includes everything from buttons, linear and radial sliders, touchpads, and a whole lot more.
The simplest cap sense pad is just a filled polygon on the top layer of a board, but this simple setup isn’t ideal if you want to use Eagle’s autorouter. By playing with the restrict layers in Eagle, PatternAgents were able to create easy cap sense buttons that will work perfectly, without the problems of the autorouter placing traces willy-nilly.
There are more than enough parts to replicate a whole lot of touch interfaces – buttons can easily be made into a smallish keyboard, and the radial touch sensor will emulate the ‘wheel’ interface on an iPod. Very cool stuff, and we can’t wait to see these in a few more boards.
It’s taken over a year, but [tinkering techie] has finally completed his touch sensitive nightstand. At first glance, it looks like any normal piece of furniture. With the addition of an Arduino, some copper clad board, and a few LEDs, he’s turned it into a very elegant, electronic home furnishing.
The nightstand is built out of a few very nice pieces of mahogany. Underneath the top of the nightstand, three Kapton-covered copper clad boards are inset along the front and side edges. These capacitive sensing boards are connected to an Arduino Fio that reads the capacitance of these sensors and turns on a small LED under the drawer or the mains powered lamp.
The electronics are powered by a small USB charger with a battery backup all hidden underneath the top of the nightstand. Inside the drawer, a magnetic reed switch turns on an RGB LED whenever the drawer is opened.
While the nightstand itself is a wonderful piece of woodworking, we need to tip our hat for a remarkably seamless integration of fine furniture and electronics. The electronic furniture modifications we usually see are Ikea cruft, but this wonderful homemade nightstand should last decades or centuries.
Video of [techie] going over his build below
Continue reading “Beautiful Touch-Sensitive Furniture”
You don’t have to have high-quality parts to play around with electronics and here’s a great example. [Vishal] used junk to play around with CapSense, the touch sensitive Arduino library. What he ended up with is this touch-based piano keyboard.
We’ve featured the CapSense library in the past, but even that example uses a very meticulously crafted test rig of foil tape, protoboard, and some resistors. If you still haven’t given it a try follow this example of using aluminum foil, electrical tape, and a cardboard box.
[Vishal] just sandwiched the end of jumper wire between two pieces of foil to make each ‘key’. We believe the other end of the wire is soldered to the bias resistors where they connect to a couple of pin headers. The headers were hot-glued in place through holes in the bottom of the box, making the entire rig simple to plug into the Arduino board driving it. After adding in a small speaker and flashing the code he’s finished. It certainly makes for a short afternoon project which you won’t feel bad about taking apart later since you didn’t sink a ton of time or resources into the build.