This rig will take the letters you write on the touchpad using a stylus and turn them into digital characters. The system is very fast and displays near-perfect recognition. This is all thanks to a large data set that was gathered through machine learning.
The ATmega644 that powers the system just doesn’t have the speed and horsepower necessary to reliably recognize handwriting on its own. But provide it with a dataset to compare against and you’re in business. [Justin] and [Stephen] designed a neural network algorithm that took a large volume of character handwriting samples, and boiled them down into a set of correlations that can be referenced when encountering a new entry. This set is about 88 kilobytes, too much to store in the microprocessor, but easy to reference from an external flash memory device.
There’s plenty of gritty details in the write up linked above, but you may want to start with the video overview found after the break.
Continue reading “Machine learning lets micro decode your handwriting”
[Andy Brown] has been working on a series of tutorials revolving around the STM32 processor family. He’s using the STM32plus development board, with an STM32F1 ARM Cortex M3 processor to drive a couple of different full color graphic LCD screens. His latest installment shows how to read from the touch screen included with both displays.
After the break we’ve embedded the video from which this screenshot was taken. As an example, [Andy] has programmed a painting program to show off what the touchscreen overlay is capable of. It starts off with the calibration routine we’re all familiar with, then drops to this screen with a virtual control panel and blank canvas.
This hardware uses the Texas Instruments ADS7843 controller, which [Andy] says is extremely common and that several other manufacturers use the same communications protocols. He discusses how to communicate with the controller, and how to incorporate the data into your program. Included is an open source library which you can use in your own projects.
Continue reading “Using a touch screen with an STM32 microcontroller”
Forget Microsoft Surface, what do you think about having a 32-inch Android-powered touchscreen display in your living room? That possibility might not be too far off, thanks to the engineers over at SKR Technology in Japan.
Primarily a company that designs and builds digital signage, they were approached by several customers who wanted a large screen device that had multi-touch functionality similar to a smartphone. Since they frequently work with Windows, they tried building a solution around Windows 7, but it just didn’t function as smoothly as they would like. Instead they turned towards Android, but were disappointed to find out that none of their suppliers supported the OS.
Instead of scrapping the project, they build their own interface that allows an Android-powered device to interact with multi-touch displays. As you can see in the video embedded below the display works quite well, mirroring everything on the Android device’s screen.
While the product is not yet available commercially, we should see it come to market later this year. We hope to see an open source version sometime in the future as well, even if we can’t quite afford a 32” touch panel display.
Continue reading “Running Android on large touch screen displays”
[Jane] wrote in to let us know about the touch-based synthesizer she and her classmates just built. They call it the ToneMatrix Touch, as it was inspired by a flash application called ToneMatrix. We’re familiar with that application as it’s been the inspiration for other physical builds as well.
A resistive touch screen in the surface glass of the device provides the ability to interact by tapping the cells you wish to turn on or off. Below the glass is a grid of LEDs which represent sound bits in the looping synthesizer track. Fifteen shift registers drive the LED matrix, with the entire system controlled by an ATmega644 microcontroller. Although the control scheme is very straight forward, the jumper wires used to connect the matrix to the shift registers make for a ratsnest of wireporn that has been hidden away inside the case. Check out the demonstration video after the break to see what this looks like and sounds like when in use.
Continue reading “Touch-based synthesizer is a wiring nightmare”
Take a PIC 24HJ256GP206 processor and add a dash of knock-off touchscreen and a pinch of SD card compatibility for a DIY digital picture frame. [Daniel] wrote his own driver for the HX8347 controlled LCD that can achieve 15 FPS at 320×240 resolution with 16-bit color. As this was a gift for his wife, [Daniel] included a heart-shaped ring of LEDs that fade in and out like an electronic pulse. He notes that the JPEG decoder runs rather slow but that’s mostly because of the bottleneck caused when accessing data from the SD card. We’ve got more pictures and a link to the source code after the break.
Continue reading “PIC based picture frame”
[Owen] got down and dirty by adding a touchscreen to his TI-84 graphing calculator. The dirty part is the z80 assembly code he wrote to use the linkport as a UART (assembly always makes us feel queasy). Once that was working he implemented some commands using an Arduino and then hooked up an Nintendo DS touch screen. Now he’s got this proof of concept video where he draws on the screen, that input is interpreted by the Arduino, commands are sent through the UART, and the calculator program draws on the screen. Adding a touch screen to something is a lot more impressive when you have to go to these lengths to get it working. Nice job!
[Peter] deserves an award for doing more with less. He’s built a handheld device based on an AVR controller that has features normally associated with much more powerful devices. Here’s what it doesn’t do: no phone calls, no text messages, no accelerometer, and best of all no app approval needed. What it does do is leverage inexpensive, readily available components combined with common homebrew development techniques to create a touch sensitive handheld.
The demo video embedded after the break details the device playing video, rendering 3D objects, and displaying pictures and ebooks with touch scrolling. All of this is running at 60 fps for a smooth picture. The whole thing is no larger than the 320×240 LCD that he salvaged from a broken MP3 player. An Atmel AVR ATmega644 microcontroller ties together the display, a resistive touch screen, and a microSD card for storage. The chip also controls the backlight, a Lithium Polymer battery, and uses USB for PC connectivity, charging, and even a mouse or keyboard interface. He etched the PCB himself for surface mount components and managed to do it with just four jumpers needed on the underside.
This is a big leap forward from the last AVR based touch sensitive device we saw. All of the functionality seen in the demo is run using 4k of memory and 32k of programming space. Because [Peter’s] powering this at 3.3v the system clock is limited to 12MHz but he’s managed to make it work. We asked him to post code and schematics and he didn’t hold back. Head over to the microtouch project page to download the code, Eagle CAD files, and PCB artwork. All of the demo files are there just waiting for you to build on his hard work. When you’ve got something running, don’t forget to share it with us!
Continue reading “8-bit device quenches iPhone envy”