Mar 31
TimUncategorized
A few weeks ago I saw an interesting Sonic Bomb Alarm Clock over at ThinkGeek. Being the ever aspiring young hacker, I decided that it wouldn’t be terribly difficult to implement something similar on my own.
Finding an alarm clock was easy enough. I snatched up an AC powered alarm clock for $5. Surprisingly the store offered a cheaper model that included AM/FM radio, but I opted for the basic clock for the sake of simplicity.
Deciding how to implement the “bed shaker” was decidedly more difficult. I uncovered two old-school Nintendo64 rumble paks. They’re a little bulky, but I decided they could do the job. What’s more, they have their own 2xAA power source, so I wouldn’t pull any power away from the clock. I probed the rumble pak’s board for a while and eventually found two solder joints that, when shorted, caused the rumble pak to, for lack of a better word, rumble.
At some point I shelved the idea of using the rumble paks in favor of a more professional approach. I decided tap into the power of the clock directly, hoping that a parallel circuit would be capable of driving enough amperage to power the clock and two small DC motors simultaneously.
I poured over the alarm clock for quite a while. I couldn’t find a timing device on the clock, so I made the assumption that the clock was using the alternating current as a timebase. I was discouraged because I know very little about AC circuits other than apparently it’s pretty dangerous. I sat down with the clock again today for another look. I was pretty confident that there would be DC power somewhere in the circuit to provide power for the IC chip. As soon as I sat down, I noticed the three diodes located near the incoming AC voltage. Sure enough, I had found a steady 12VDC power source.
My plan was to use a simple NPN transistor in series with the motor, and a capacitor to smooth out the voltage. I wagered that I could jumper a lead from the buzzer and siphon enough voltage to activate the base of the transistor. If all went according to plan, the vibrations would be synchronized with the sound of the alarm.
Of course nothing works out as originally planned. Even the tiny motor that I used for testing pulled too much current from the clock circuit, causing it to reset each time the alarm sounded. I tried using various resistors, ranging form 5k ohm to around 470 ohm to no effect (in retrospect I should have slapped a potentiometer in the circuit for testing). The power source could only output enough amperage to power either the clock or the motor, not both.
I was still concerned that my concept may be flawed, so I logged onto the ##electronics channel on the Freenode IRC server and asked the professionals there for some assistance. To my surprise, they informed me that my concept was indeed valid, and they confirmed my suspicions that the power supply simply couldn’t provide enough amperage to power both circuits simultaneously. The nice folks there gave me some good information about DC motors, how they actually require a relatively large power surge to get started, and recommended that I place a power diode between the motor and the transistor to prevent the fluctuating currents from the motor from destroying my transistor.
Overall, even though I wasn’t able to complete the project tonight, I’m still very pleased with my progress. I have several distinct options to proceed from this point:
- Return to my original concept using the rumble pak’s with their self-contained power supplies.
- Attempt to locate a power source that will provide 12VDC with more amperage.
- Wait for my Digital Alarm Clock Kit to arrive, which has a 12VDC relay already built-in.
I’ll try to get some pictures posted on the imagitronics project site of tonights festivities.
Mar 30
TimUncategorized
I was more than a little disappointed this morning when an RSS feed informed me that some enterprising young hacker over at Hacked Gadgets had created an Alarm Phone Dialer. If you’ve been keeping up with my Tumblelog, you could probably deduce that I was working on a similar design myself.
Gradually, my disappointment gave way to inspiration. Obviously my idea held some merit or the Hacked Gadgets post wouldn’t have found it’s way to the Make: blog, nor the other eight blogs monitored by Technorati that made mention of the project. I began to relish the idea that my own ideas were appreciable outside of my own imagination. The truth of the matter is that nearly any idea you can possibly conceive, there’s a strong likelihood that someone has already attempted it, accomplished it, or at least thought about it. Why should I be disappointed that another like-minded individual had the necessary skills to bring his design to life?
With that in mind, I’ve decided to start sharing a little more about the upcoming projects that I’ve been planning. I’ve been keeping things under my hat in hopes that other hackers with more experience than myself wouldn’t discourage me by getting their project recognized first. That kind of thinking is counter-intuitive of the free and open internet society that I claim to support. If someone is inspired by one of my ideas and wishes to implement it before I figure out how, all I ask is that they notify me so that I can learn from their experience. If you happen to know of any similar DIY projects or or commercial products, I’d like to hear about those too!
Mar 25
TimUncategorized
We Mac users are an interesting breed.
In many ways being a Mac owner is akin to being a Jeep owner. It always fascinated me how when two Jeeps pass on the road, the owners wave to each other like old friends. It’s as if they know something the rest of us haven’t figured out. You’ll often see the same kind of camaraderie from bus drivers, taxi drivers, boaters, and motorcycle riders, but it’s not often that you find that kind of connection in the computer world.
I’ve been thinking about this a lot since the local Military Exchange stores started to carry iMacs. Now, every time I go to the exchange I feel compelled to swing by the Mac display, which always has a crowd of 5-10 people standing around fawning over Cupertino’s latest. Once there, I’ll answer questions about the Mac’s and attempt to alleviate customer fears. Yesterday I spent 45 minutes doing just that, and ultimately sold two Macs in the process.
What surprised me though was that when I left the store, I made another pass by the Mac display. This time there was another Apple Aficionado there. I listened quietly while he passionately pitched the many benefits of making the switch. It was an amazing experience to me.
When was the last time you saw complete strangers taking the time out of their schedules to educate others on the benefit of their new PCs. I’m sure it happens, but I’ve never witnessed it.
Mar 24
TimUncategorized
I created a Tumblelog today. If you’re unfamiliar with the term, a tumblelog is is a kind of media-centric blog that’s based around short, simple entries. I intend to continue sharing my experiences here on LJ, and using the tumblelog to keep track of my thoughts. Whenever I find an interesting article, quote, or link that I plan to research in more detail, you’ll find it on my tumblelog.
Hopefully this will allow me to concentrate on more relevant articles here, while posting my more mundane topics elsewhere.
You can also check out my del.icio.us bookmarks. I tag a dozen or so interesting web pages every day. Astute visitors could easily determine my upcoming project ideas based off the sites I’m currently tagging.
Mar 22
TimUncategorized
Learning electronics principles on your own can be a very daunting task. This isn’t the first time that I’ve set out to learn about electronics, but it has certainly been my most productive attempt thanks to a couple of great books, and the methodology I’ve adopted when reading them.
I treat my education in electronics exactly the same as any collegiate course. My primary textbook is
Teach yourself Electricity and Electronics (4th ed) by Stan Gibilisco. The author recommends reading the book slowly, one chapter per week over the course of nine months. I couldn’t agree with him more. One of my biggest pitfalls is that I rush through things. Classroom education is based on the principle of repetition, this is the element that has been missing from my personal education. I decided to treat this book as if it were a paid course at the local University. I read each chapter, then pour through the chapter a second time, taking notes. Each chapter in this book is followed by a short quiz, and I treat them accordingly. This system was working well. The book is an excellent resource.
Unfortunately, after nearly two months of dedicated study using Mr. Gibilisco’s book, I hadn’t even touched a single component. The book teaches excellent theory with practical examples, but comes up short for hands-on experience. What I needed was an accompanying lab workbook.
Enter Dave Cutcher’s Electronic Circuits for the Evil Genius. This book reads like a lab manual, you’ll be creating (and more importantly, understanding) useful circuits from day one. To simplify things, I also picked up the Evil Genius component kit from Abra Electronics. This kit comes with all the components, printed circuit boards, and prototyping equipment that you need to build every project in the book.
These books compliment each other surprisingly well. Mr Gibilisco’s book does an excellent job of teaching electronic theory and design, while Mr. Cutcher’s approach gives you hands on experience building and testing simple electronic devices of your own.
I highly recommend these two books for anyone who wishes to undertake hobbyist electronics on their own.
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