I was thinking about buying a BoArduino for easier prototyping…it’s easy and cheap, but not as cheap as I am apparently. I decided to build my own instead using an old proto board, some pin headers and CAT5 cable I had laying around. It’s not nearly as pretty, but just as functional, and I don’t need to reload my code to the arduino I plan on using in “production” because I actually built it in shield format. I’m working on a prettier version, using that as a pet project for learning Eagle PCB layout. But for now, this works just fine.
Since I started in IT, I’ve always been a scavenger of sorts. Ripping out hard drives, memory, fans, coin cell batteries…you name it. But it wasn’t until I started building electronic circuits that my scavenging tendencies really started to run rampant. There are numerous electronic goldmines all around us, that if you’re willing to open your eyes and tap into these resources, you can save yourself a bundle of money, and sometimes even open up new ideas for projects or solutions to existing projects. One my most recent discoveries of one such goldmine can be found in public facilities everywhere: the automatic paper towel dispenser.
While at work, I was walking by a garbage can and noticed one of these dispensers. It almost screamed my name as I walked by, did a double-take, and stood there for a moment to think it over. With a quick look around I made sure no one was around, I snagged it and ran for my office. I hovered over the the dismantled appliance with an evil…OK, not really…but in about 5 minutes I did have myself a nice little collection of trinkets to play with. A short list of components: 5V DC motor with matched gears, 3 or 4 different types of switches, and momentary buttons, a proximity sensor (I haven’t quite figured out how it works yet), a few LEDs, and a board chock full of diodes, resistors, and other miscellaneous components (if you take the time to de-solder).
It is my understanding that these things are very easy to find in the dumpster because they are given out by the paper towel companies whenever a company orders of product are purchased. I guess their thought is, wherever there’s a paper towel dispenser, there’s bound to be paper towels. So the more they give out, the more product is sold. Also, most maintenance people don’t even bother changing the batteries, they just grab a new one from the back closet and throw the old one in the garbage.
OK, so what’s the take-home lesson? Keep your eyes open…one man’s garbage is another man’s robot. You never know what could be salvaged out of an old answering machine, TV, network switch, radio, or even paper towel dispenser. Oh ya, and please don’t go ripping these off the wall the next time you’re in your local 7-11…they’re actually kind of handy when they work. : )
I received my first Arduino in the mail the other day. Of course I went through all the tutorials and started tinkering right away. But I won’t bore you with those details…God knows there are too many “I plugged in an LED and got the Blink program running” out there already. But I did design a quick little circuit that I thought might be handy as a tutorial for beginners (like myself).
For the physical setup, all you need is an LED with a 220Ω resistor connected to pin 11, and a photocell connected to pin 2 with a 5V pulldown configuration (see pictures). I’ve attached the sketch code to the post…upload the sketch to your Arduino and say goodbye to the boogie monster. Click here to download sketch code.