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.
Continue reading “Reaching out to a touch screen with a microcontroller”
[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.
Continue reading “Touch-based wirless RGB lamp control”
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”
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.
Continue reading “Capacitive touch sensor shield for the TI Launchpad”
Wanting to save space and weight on his project build [Florin] set out to find a way to add Ethernet connectivity without the magnetics. His ill-advised first try involved directly coupling two switches, frying both in the process. After some research he found that Ethernet hardware manufacturers have considered the need for devices without the magnetics and there are several application notes available on the subject. [Florin] followed the information that Realtek has for their devices and learned that they can be couple capacitively. After depopulating the magnetics from a second pair of switches he wired up some resistor-capacitor networks on a breadboard and got the connecting to work.
The chill of autumn is upon us, and with it comes the awkward sport of trying to work touch-sensitive phones and gadgets with gloved fingers. One can try toughing it out with fingerless gloves, or we’ve seen some costly solutions in the forms of specialized gloves and capacitive-compatible styluses, but sometimes simple is best: all it takes is a few stitches of conductive thread in the fingertips.
Conductive thread is available from various sources; SparkFun Electronics comes naturally to mind, but most vendors carrying the LilyPad Arduino will stock a suitable thread as well. Don’t fret if you’ve never sewn before — just a few simple loops are required, and it doesn’t need to be especially tidy. In principle this should work for trackpads and capacitive mice as well, if you use those in the field. For multitouch devices, add a separate conductive bit to each fingertip.
That title’s a mouthful but you’re already familiar with the technology and application of foot pads as sensors in games like Dance Dance Revolution. The usbddr project sought to make a USB connected DDR controller from scratch. The microcontroller used is an Atmel ATmega8 running the V-USB firmware for connectivity and uses the analog to digital converts to read in data from the capacitive sensors.
The physical implementation is cleaver. The base plate has a capacitor plate attached to the top of it and the tile has the other capacitor plate attached to the bottom of it. The two are separated by some weather-stripping which is spongy enough to allow compression, bringing the two capacitor plates together.
We’re not convinced of the long-term durability of the system. We certainly don’t think it will hold up to very much hard-core DDR playing. But we would love to see a Super Mario RPG style puzzle to unlock the door to the ‘castle’ at a child’s birthday party.