Lazy Labor Day Educational Time. Watch Cornell’s Microcontroller Courses.

September 2, 2012 by 13 Comments

 

C’mon, you know you’re not really going to do much today. You might as well spend that time learning some skills instead of watching funny cats. The Cornell ECE lectures on microcontrollers (ECE 4760 and ECE5760), taught by [Bruce Land], are available online for free.

Not only do you get to enjoy these two courses, but there are videos available showing off several different categories of student projects as well.

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BGA Soldering With A Paint Stripper And Stopwatch

August 27, 2012 by 22 Comments

Having just received a shiny set of PCBs from the fab-house [Devbisme] needed a way to solder the main chip in place. It has a Ball-Grid Array footprint which is notoriously difficult to populate in a home lab. But he makes it look pretty easy and decided to share a video tutorial of the process.

The main tool he used is the paint stripper (heat gun) seen above. Since he didn’t have his own fancy reflow oven he made things work with the gun as his heat source. First he applies a generous layer of liquid solder flux to the BGA footprint on the board. Next he melts some solder onto the tip of his iron and uses it to tin all of the board’s BGA pads. Then it’s time for the critical step of positioning the chip. He uses vacuum tweezers to set it in place, and traditional tweezers to fine-tune its position. From here he heats with the paint stripper for two minutes, starting far above the board and slowly moving closer, with the reverse at the end of the soldering process. Once cool the board is cleaned with distilled water and blown dry with compressed air. After a visual inspection he finishes the application with a 30 minute stay in a 300 degree oven. We’ve included the video after the break for your convenience.

We’ve seen a similar technique used for replacing a chip on an already populated board.

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Using A Watch To Control Ms. Pacman

July 20, 2012 by 4 Comments

Recently, [Alan] broke out the ‘ol Atari 2600 to relive his childhood with a bit of Yar’s Revenge and Adventure, but after looking at his new TI EZ430 Chronos watch, he figured he could add a bit of motion control from this classic game system. He used the accelerometer in this watch to play Ms. Pacman by tilting his wrist, an awesome build that really shows off the power of his new wrist worn device.

The watch is running stock firmware and communicates to a PC via an RF module attached to his computer’s USB port. The accelerometer data is fed into a VB.net app to convert the movements of the wrist into up, down, left, and right commands. These commands are then sent out over a serial port to an Arduino to translate those commands into something the Atari joystick port can understand.

Sure, it may be a roundabout way of playing Ms. Pacman, but considering the TI Chronos has been used for very serious work such as stopping SIDS and helping out soccer referees, we’re happy to see a more frivolous application for this neat watch.

You can check out [Alan]’s video after the break, or get the VB and Arduino source here and here.

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TI Chronos Watch Monitor Your Sleeping Infant

July 4, 2012 by 21 Comments

[Bill] wants a little piece of mind when his infant is sleeping in the other room. For him, the audio-only baby monitor could use some improvement. His proof-of-concept is that blue patch Velcroed on the swaddled infant. It monitors movement, orientation, and temperature and alerts you when something’s amiss.

Inside the pouch you’ll find a TI Chronos eZ430 wristwatch with the band removed. It’s a nice hardware choice because it includes an accelerometer, temperature sensor, and RF link to a USB dongle. [Bill’s] code sends a data packet to the PC about once a second. The PC watches to make sure there’s slight motion, indicating the baby is breathing. This part doesn’t work all that well as the accelerometer doesn’t pick up tiny movements all too well, but it does have potential. In the video after the break you can see the functions which make sure the baby doesn’t roll onto its belly, and that she’s not too cold do work extremely well.

We wonder if the accelerometer would pick up more motion if the watch was hung from a string inside of a small enclosure. This way it would swing back and forth with small movements. But perhaps that would make the whole thing too bulky?

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Ti Chronos Watch Controls Raspberry Pi

July 3, 2012 by 9 Comments

[Mike Field] was working on interfacing his TI Chronos eZ430 watch with the Raspberry Pi. As things were going pretty well, he took a side-trip from his intended hack and implemented watch-based control for an RPi audio player.

It really comes as no surprise that this is possible, and even easy. After all, the RPi board has native USB capability for hosting the watch‘s RF dongle, and it’s running Linux which we know already works well with the Chronos platform. But we still love the thought of having automation controls strapped to our wrist!

mpg321 is the audio playback program used for this hack. It plays MP3 files using ALSA for sound, which does have a few hiccups on the RPi. [Mike] found workarounds and included them in the C program he uses to gather everything into one nice code package. Control depends on keypresses sent from the watch (meant for use with PowerPoint) which are translated by his code and pushed to the audio/mp3 programs.

Pocketwatch Retrofit Takes Input From Accelerometer

June 8, 2012 by 6 Comments

A friend of [CNLohr’s] used the mechanism from an old pocket watch in an art piece, but left him with the enclosure. It’s an interesting looking object that feels great in your hand so he decided to fill it with his own electronics, thereby giving it a new life. He’s showing off an early version of the hardware in the video, but plans to send off another version of the board soon to add a few features.

You can see that the round PCB is small enough to fit in the space vacated by the original hardware. The ribbon cable is used to connect to the programmer and we think it’s also the power source for this demonstration. There’s a small Densitron display that’s reading out hex values from the accelerometer. Many of these mems chip (you can learn how they work from this post) include a hardware tap detector. This meant you can tap your finger on the device and the chip will signal an input to whatever chip is attached to it. That’s a great option for user input, and it’s what [CNLohr] chose as the select button here. He tilts the watch to one side, then taps to turn on the LED. That’s all for now, but we like the promise it shows and can’t wait for updates!

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Heliowatcher Positions Solar Panels For Highest Efficiency

May 21, 2012 by 17 Comments

[Jason Wright] and [Jeremy Blum] are showing off the project they developed for their Designing with Microcontrollers course at Cornell University. They call it the Heliowatcher, and if you know your Greek mythology we’d be you figured out this watches the movement of the sun and adjust a solar panel to follow it.

Their design is simple and effective. The base is mounted like a Lazy Susan, able to pivot on the horizontal plane. The bottom edge of the solar panel is mounted with two door hinges, with a motorized screw jack used to raise and lower it. The system uses a GPS to provide geographical position, day, and time feedback. This is used in conjunction with an array of four LEDs to determine the best position of the panel. Those LEDs are acting as light sensors; when the top and the bottom detect similar levels, the panel is at its most efficient orientation. The left and right LED sensors work the same way.

Now if we can just work out a self-cleaning system to keep the panels free of the dirty film that builds up over time we’d be set!

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