[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. Continue reading “Automatic Closet Lightswitch”
[Sultan Qasim] wrote in to tell us about the work he’s been doing on the Stellarino library. It’s goal is to break down the coding barriers present for those looking to move from Arduino to ARM. This is accomplished by facilitating Wiring-stlye code for the Stellaris Launchpad ARM development board.
Right off the bat [Sultan] mentions that the interface is Wiring-like, but is not compatible with it. This means you can’t just plop your existing sketches into a C file and get them to work with the addition of a simple include file. But what it does do is provide access to the functions to which seasoned Arduino users have grown accustomed. You can see some examples above, including analogWrite(), digitalRead(), and a simple delay function.
We had a quick look at the library. It uses StellarisWare components which are stored in the ROM of the chip (these are all preceded by ‘ROM_’). The one thing missing is the UARTstudio library which apparently carries a license incompatible with GPL.
[Shachar Geiger] sent in an interesting project that he worked on with [Tal Avivi] at the Bezalel academy in Jerusalem. They were given the task of designing a 1-person electrical urban vehicle. They took some cues from MIT’s Transology and designed the OmniDirectional Research Platform (ODRi). There’s a video of it embedded above. It can be driven using three different input styles: an accelerometer joystick, a traditional gamepad, or body mass shift. They started with an Arduino, but needed more I/O and had to switch to a Wiring board (this was before the Mega). The platform is built mostly from scrap. The accelerometers were placed in an old Microsoft Sidwinder. The standard joystick is from a Sega Mega Drive. The weight sensors are out of cheap home scales.
[Marcus] has written up his experiences using the AD7746 capacitance sensor. He used the SparkFun breakout board in conjunction with an Arduino. The available Arduino code wasn’t that great so he rewrote it to be easier to understand. The AD7746 is an I2C device that can be continuously read, but this doesn’t mesh well with the Wiring libraries. Additionally, the calibration routine from the data sheet is difficult to understand. He’s included all of the code he used plus a Processing sketch to help visualize the input which will hopefully make your experience with the chip much more smooth.
[jelengar] liked the ease of use of the Arduino, but wanted a much higher pin count. He set about converting the ATmega Controller for use with Wiring, the code that the Arduino IDE is based on. The ATmega128 in the controller features 53 pins as opposed to the 11 on the Arduino’s ATmega168. You also get 128kb of memory. The process is fairly simple; you just need to add the appropriate crystal. You can also add a switch to trigger the bootloader and a status LED.
So here’s the situation: you have an audio device, maybe a boombox, perhaps one you built yourself, but it has no VU meter. No problem; building a VU meter is easy with these instructions from [Joe].
You’ll need either an LM3915 or LM3916 chip, a couple of bread boards, two audio jacks, ten LEDs, and a few other components. Wire them all together per the schematic, then plug an audio source into the input jack. You can plug your speakers or output device into the output jack, and you’re done. Keep in mind that LM3916s switch negative, so positive to positive wiring from LEDs to the bread board will be necessary. The wiring on [Joe]’s version is a bit convoluted, but it can be cleaned up on yours if you take the time. Video embedded below.
Continue reading “VU Meter made with an LM3915″
Normally driving an LCD requires seven connections to pins on the display, but by using a shift register, [Phillip Warner] at Arduino Playground was able to drive an LCD using only 3 wires. The method is cheaper than a serial LCD, but you’ll mainly save yourself a lot of effort and time by using it.
[Warner] used a HEF4094 chip to group the lines together and a variable resistor to control the contrast. A zip file with the requisite code to make this work can be found in the post.