Sunday, December 12, 2010

15 Minutes of Fame, Some Comics, and a pair of Headphones

'Morning everyone,

Just a quick update before I hit the books in preparation for my last week of exams.

Last week had it's trials and tribulations, but there certainly were highlights. I was down in the dumps after a less-than-stellar performance on a C programming final exam, but was soon back on cloud nine when a friend told me that my Bluetooth Thermometer project had been featured on Hack-a-Day. Very exciting!

Though it is not fairing nearly as well (yet), I created an Instructable that details the Arduino Bracket.

Though I have spent the majority of the weekend studying, I did manage to scrawl out a few new comics and post them here. As I was reviewing I came across a number of goofy little sketches and scribbles hiding amongst all the circuits and math notes. I went over them in black Sharpie, scanned them, and have posted them on my site for your enjoyment (or amusement). One quick look should make it blatantly obvious why I am in electronic engineering and not arts ;-).

Now - Some Electronics! Here are my current top electronics projects:

Project 1: ThermoPhones:
Like many people, I have the bad habit of turning the volume on my iPod down almost all the way and leaving the device running on a table so that it is good and dead the next time I want to listen to some tunes. The other night I was out for a walk and a plausible solution hit me - make the headphones heat-sensitive!

Figure 1.0: iPhone Headphones with Thermistor Epoxied

 It's not much, but it is a start. I wired the thermistor up to an Arduino for prototyping convenience, and was able to see a 10c difference between when the headphones were sitting on my desk and when they were in my ear. The idea is that when the microcontroller sees a temperature drop of, lets say 5c in less than one minute, it issues a "pause" command to the iPod. Since it is looking for a change in temperature, it shouldn't have too much trouble when the user goes outside, but this might require further investigation.

Ultimately, the controlling would be done by a tiny microcontroller such as a PIC10F200, and the entire thing should be able to leech enough power to operate from the iPhone/iPod. Hopefully I'll have a chance to get some work done on this project over the Christmas holidays.

Project 2: Auto Rear Window Defogger
Everyone knows that I hate all things manual, and that I consider something as trivial as pushing the button to turn on the rear window defogger in my car to be manual labor. It's not because I'm lazy, it's because the year is 2010. It really shouldn't be that difficult for the car to figure out if the window is frosty, and for it to take action if it is.

Figure 1.1: IR RX/TX pair on a Breadboard with an Arduino (and bracket!)

This project is also still in diapers, but really shouldn't be too difficult to get going. The basic idea is that it will bounce a beam of infrared light off the inside of the car window, and the amount of light received back by the phototransistor will change depending on how clear the window is. If the window is foggy/frosty, more light should be reflected, telling the microcontroller to turn the defogger on. Once the reflected light drops below a certain threshold, it means the window is clear, and defogger should be shut off.

The above circuit is just a rough draft, ultimately it will need some degree of filtering and other noise reduction measures, and of course a relay to control the actual heater. Once I get the voltage levels tweaked and the basic system operating I will port the code over to Hitech C and burn it onto a PIC microcontroller; most likely a PIC12F675. If all goes well the entire board should be less than 50mm x 50mm, which shouldn't be too noticeable in my back window.

That's all I've got for now - I don't know how much progress I'll make on either project this week, but over Christmas I should at least be able to get some of the code written and the hardware designed.

If I don't have a chance to post anything before then, Merry Christmas, Happy Haunakah, メリークリスマス, Joyeux Noel, Feliz Navidad, Geseënde Kersfees, Gun Tso Sun Tan'Gung Haw Sun,  and I'd like to extend the warm wishes to anyone I've missed :-).