MSP430 touchscreen piano

msp430-touchscreen-piano

[Rohit Gupta] wrote in to share this touchscreen piano project he built around the TI Launchpad. It provided a way for him to explore using a resistive digitizer found on a lot of mobile devices. These are simply stuck to the top of LCD screens and replacements are inexpensive, but salvaging one from old hardware is an option as well.

The first thing he did was to test the four outputs of the digitizer with his multimeter. Logging the changing resistance will help make sure you’re reading the correct wires and are able to zero in the settings before you start coding. [Rohit] uses the ADC on the MSP430 chip to read from the screen. He went with the algorithm from one of TI’s app notes to convert the readings in to X and Y coordinates.

He separated the screen into seven columns, each generating a different tone. Touching higher or lower on that column will alter the pitch of the note produced. You can hear an example of this in the demo after the jump.

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Chromebook hack controls your television

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[Michael Kohn] only accomplished about half of what he set out to, but we still think his TV channel switcher from a Chromebook turned out nicely. When starting the project he wanted to include a grid of listing so that he could choose a specific program, but decided that scraping the data was too much work for this go-round.

The Chromebook doesn’t include an IR transmitter so he built one using an MSP430 chip. He had previously built a little transmitter around an AVR chip and was surprised to find that the internal oscillator on that was quite a bit more accurate than on the MSP430. Timing is everything with the Manchester encoded signals used for IR remote controls so he used his oscilloscope to tune the DCO as accurately as possible.

The app shown on the screen was written in Javascript. Google published some example code on using RS232 with the computer; [Michael] used this resource to provide communications between the computer and the microcontroller.

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Automatic Closet Lightswitch

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[Dillon] wrote in to tell us about his latest project, an automatic light switch for a the hallway closet in his house. Although this project could probably be done very simply, [Dillon] accomplished everything in a way that actually looks professionally done and has some neat features. Check out his site for more pictures of the build.

Not that we at [HAD] mind a bit of messy wiring, but if it’s going inside a house, neater is always better. On the other hand, this project took nearly a year to go from idea to implementation, so please keep submitting your spaghetti-wired projects.  We understand.

As an electrical engineering major, [Dillon] didn’t skimp on basic electrical components, and has schematics available on his site. A MSP430 microcontroller provides the “brains” for everything, turning the light off after 5 minutes if the doors are not shut. Be sure to check out his video overview after the break with footage of it in action. [Read more...]

Making it Easier to Build Firmware

OSHW Logo

Most microcontroller manufacturers give you some kind of free development toolchain or IDE with their silicon products. Often it’s crippled, closed source, and a large download. This is pretty inconvenient when you want to have firmware that’s easy to build and distribute. I’ve found many of these toolchains to be annoying to use, and requiring closed source software to build open source firmware seems less than desirable.

It’s possible to build code for most microcontrollers using command line tools. You’ll need a compiler, the device manufacturer’s libraries and header files, and some method of flashing the device. A lot of these tools are open source, which lets you have an open source toolchain that builds your project.

Setting up these tools can be a bit tricky, so I’m building a set of templates to make it easier. Each template has instructions on setting up the toolchain, a Makefile to build the firmware, and sample code to get up and running quickly. It’s all public domain, so you can use it for whatever you’d like.

Currently there’s support for AVR, MSP430, Stellaris ARM, and STM32L1. More devices are in the works, and suggestions are welcome. Hopefully this helps people get started building firmware that’s easy to build and distribute with projects.

Lord Vetinari’s clock strikes again

vetinari

Inspired by the maddening timepiece from Discworld, this clock keeps time, but anyone watching the seconds tick by may be mentally unstable for it. [Renaud Schleck] built the stuttering clock using very few components. He undertook the build after being inspired by the version which [Simon Inns] built.

The clock itself is a run-of-the-mill item which uses one battery to keep time. We’re always impressed by how these dirt-cheap things remain so accurate over the long haul — but we digress. The method of attack uses coil injection to drive the hands. [Renaud] used one of the microcontrollers from the MSP430 Launchpad, along with the clock crystal which also shipped with the kit, to gain control of the mechanism. The crystal triggers an interrupt which does the actual time-keeping. The seconds hand is driven rather sporadically based on an algorithm explained in his write-up.

You can watch the uneven ticking in the video after the break. Despite that visually disturbing functionality, the short and long ticks balance each other and the correct time continues to be displayed.

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GLCD clock project packed with great UI and features

glcd-clock-packed-with-features

This Graphic LCD clock doesn’t have a fancy case, but [Gregory Wright] built in so many great features we think it will serve as inspiration for many projects to come. If he does decide to add a case it will be quite easy as there are no buttons to work around.

Without buttons how can the thing be adjusted? He decided to go with an IR remote control for all settings. This gives him a lot more options than a handful of buttons would have. Plus, heavy sleepers will need to find the remote control in order to shut off the alarm. We also think it’s interesting that the 595 shift registers he used have a low enough data high threshold (3.15V when VCC is 4.5V) that he didn’t need level converters to drive the 5V display with his 3.3V MSP430 Launchpad.

Check out his video after the break to learn about all the features he included in the UI. Our favorite is shown on the bottom right where it says “Hello World”. This is an area dedicated to a custom message for each day. He uses it to remind him about trash day (now there’s a feature!).

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Morse code flower is trying to tell you something

morse-code-flower

To the casual observer this flower looks nice as its illuminated center fades in and out. But there’s hidden meaning to that light. Some of the blinks are longer than others; this flower is using Morse Code.

[Renaud Schleck] wanted to try a few different things with his MSP430 microcontroller. He decided on an LED that looks like a flower as it will be a nice piece of decor to set around the home. To add the Morse Code message he wanted something a bit more eloquent (and less distracting) than purely digital flashing. So he took the dots and dashes of the hard-coded message and turned them into fading signals by using Pulse-Width Modulation.

He free-formed the circuit so that it, and the coin cell that powers it, would fit in the flower pot. A reed switch is responsible for turning the juice on and off. When placed near a magnet the flower begins its gentle playback.

[Read more...]

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