It’s the Great Internet Migratory Box Of Electronics Junk!

So here’s the gig: there’s these boxes of random electronics junk floating around out there, some of ‘em are packed with little nuggets of treasure.  If you’re slick enough to get your hands on one, you’re supposed to take as much junk out of the box you want, document at least one of said things, add as much junk to the box as you want, ship it off to someone else.  I managed to snag this little beauty:

That thing is a EZ Web Lynx development kit.  Those two little jack things on the right are the actual gizmo, the rest is just a development/learning platform doohickey.  But these things are incredibly cool: 11 digital I/O pins, 5 analog I/O pins, some built in support for I²C temperature sensors and character LCDs, all accessible over a web GUI.  And the thing is barely bigger than the ethernet jack itself.  Make pretty much any project you got internet-enabled.  Oh yes, fun with this will be had…

I also ganked a couple of useful cables, but I didn’t want to be greedy since it looked like I got the coolest thing in the box.  I threw in some good stuff though, including a working-but-ancient palm pilot and dock.

You should check out the TGIMBOEJ project if you want your own box.  As for this one, it’s off to Kipkay!

So here’s what I did: I went down to the local Goodwill and picked up a cheap wooden 4×6 picture frame for about a buck.  I sanded the front face of the picture frame down nice and flat.  I also snagged a motherboard that was headed for the ewaste bin and stripped everything off it (more of a PITA than you might initially think).  Try to keep one side of the circuit board clean-looking.  Then I used a dremel to cut and shape an appropriately sized hole in the circuit board.  Attach the frame to the circuit board (epoxy, hot glue, screws, whatever you got).

Since I wanted to jazz it up a bit, I got an Open Heart kit and soldered it together.  Drill a hole in the circuit board to run the wires through, and then attach it to the circuit board however you see fit.

And since LEDs that don’t light up are lame, I mounted to the back a 9v battery and an Arduino Micro with a blown FTDI chip I had lying around.  I programed the arduino to do a little animation (using the tool provided by the Open Heart kit’s maker), and sealed it up with a switch and makeshift enclosure (I used some Radio Shack D-cell battery clips).

Clean it up, and if you didn’t screw it up, you have a nifty little frame there. Plus, you can claim some green cred for repurposing a landfill-bound motherboard. I have no idea how long the battery would last, but I doubt it’d be for very long, maybe a day or two.  But it’s kinda for the novelty anyway, so who cares.  Take a nice picture of yourself, get it printed up at Walgreens or something, and you have the perfect gift for mother and significant others…

This idea was shamelessly stolen from LucidScience of course.  It’s just amazing what you can make with junk laying around the house.  And I bet if you wired in a razor blade radio instead of a microphone, the amplifier stage could make the radio work with regular headphones…

Unfortunately, I didn’t take any pictures during the build, but it’s dirt simple enough that it shouldn’t be necessary.  Also, google is your friend.  The general idea is to crack open the case, take all the different wires and sort them by voltage (pick however many voltages you want).  Drill some holes in the case for a switch, some binding posts, and some LEDs.  Some quick research will tell you which color wires are what; my power supply was nice enough to list most of them on the side label.

There’s a wire that switches the power supply on and off, so that should probably get wired into the switch.  The power supply provides a “power good” signal that is a useful power indicator that I have plugged into the green LED.  I took the 5v standby wire and hooked that up to the red LED as an indicator if the thing is plugged into my wall (why not?)  After that, I split off some of the voltage wires to a binding posts, giving me +12v, +5v, +3.3v, -5v, -12v and ground.  If you want to be able to handle higher currents, run two ground, 5v, and 12v wires to the binding posts.  You should probably throw in some fuses too…

One catch is you need to provide a load for the thing to work properly.  I took a 10Ω 10 watt “sandbar” resister and soldered it between a +5v and ground wire, which provides a field-expedient “good enough” solution.  It’ll get hot though, so I used a little thermal compound and zip ties to strap it to a heat sink inside the PSU.

It’s oddly satisfying turning a piece of junk into something useful for under $10…

Well, it turns out that you can build an AM radio receiver that requires no external power source using just some wire, a pencil, and a razor blade.  Some other goodies like paperclips, thumbtacks, and a chunk of wood make it even easier.  If you can’t manage to find those things in a post-SHTF world, you should just massage some barbecue sauce in your hair and just get it over with…


This thing works on the same principle as the classic crystal radio, but instead of a crystal, we have a razor blade and a pencil. I’ll skip all the details and the circuit diagram, but there’s plenty of info out there…

Basically, you’re gonna need a bunch of wire to make a coil.  Any wire will work, but the best stuff to use is enameled magnet wire.  You can find this stuff in transformers and motors.  Make a coil around a paper towel roll for about 150 turns.  Carefully sand the surface of the coil so the slide can make a good electrical contact, and you basically have an adjustable coil (you could instead pull a little twist of wire out every 5-10 turns and use it as a tap).  The best razor blades to use are blued safety razors, but even a regular rusty one will work.  Giving it a quick blast with a blow torch seems to help, seeing as it’s apparently some sort of oxide coating on the blade that makes the magic happen.  Wire the lead of the pencil up and use it like a cat’s whisker.

You need a good antenna and a good ground connection for this thing to work without a power source or amplifier.  A metal tent stake and some more wire works wonders for the ground, and the antenna is basically just a long length of wire as high in the air as you can get.  It helps if it’s not touching stuff, so make/use some plastic insulators for best results (punch some holes in coke bottles, they work great).

The other catch for making this thing work without an amplifier is you need high impedance headphones.  These are actually not all that easy to come across these days.  These are usually really old magnetic types or even those ceramic earbud thingies you find in crystal radio kits (the irony).  Luckily, I just happen to have an old set of working headphones that did the trick nicely.

So, provided there’s anyone actually transmitting in the AM band when it all goes to hell, at least you’ll be able to find a way to tune in for the play-by-play…

However, it is lost no more! I got a hold of him and offered him a subdomain on my site. So now, I present the original hackosis in all it’s glory: http://hackosis.chiefcrash.com/

Check it out, lots of nifty stuff there…

But, as a little side project, I’m building an alarm clock. Just for giggles. It’ll be crazy once it’s done, but for now, it ain’t much. check it out:

So in Part 2, we had managed to find a way to get our laptop to charge from the robot. Catch was, the laptop was always charging from the robot. We don’t want that. Let’s fix that…

What we need is some way of selectively connecting or disconnecting the laptop’s power supply from the robot. A common light switch would do, but that kind of defeats the whole autonomous charging ability thingie we’re going for. So we want some sort of computer controlled switch: a relay.

But our little OLPC laptop has no way of controlling a relay by itself. Maybe there’s some sort of USB gizmo out there to do this, but screw that: let’s build something. So I picked up a little Arduino microcontroller board (in this case, it’s actually a Seeeduino.) Add in a breadboard, some resistors, a diode and transistor, and we have a working relay circuit. By flipping one of the I/O pins on the Arduino, we can flip the switch and charge the laptop whenever we want. And since we can control the Arduino through the laptop, the robot can do this whenever it needs to.

What you see up this is the setup. Here’s the schematic. I simply took the power cord running from the robot to the laptop, cut one of the wires, wired the relay into the gap, and presto!

Since we got this fancy microcontroller thingie here, why not get a little more use out of it? You might notice those extra wires taped off to the side. One of those goes to the power toggle pin of the robot’s cargo bay connector. By sending little pulses to this pin, we can turn the robot’s power on or off. We couldn’t do this before. Sounds like something that might come in useful…

Another one of them connects to the “charging source available” pin in the cargo bay connector. We can pull sensor data from the robot and tell this, but this seemed like a nifty thing to have (especially since we can’t pull sensor data if the robot is off but charging.) This way, I can just poll one of the Arduino pins and can quickly tell if the robot is connected to a charging source (docking station or plugged in). I thought about using this pin to drive the relay by itself, but there’s advantages to having the relay controlled via the computer.

Another one of those wires simply connects to the robot’s 5v reference voltage. This allows us to tell if the robot is on or off (sounds like a stupid thing to need. It isn’t.)

The black thing in the picture is a little piece of 3-ring binder I cut and shaped to serve as a cover/deck for the cargo bay. I tucked as many wires as I could into the cargo bay, fed them through a little hole, then screwed down the binder piece. I stuck the little arduino and breadboard to a harness that came with the arduino, and used a piece of velcro to stick it to the binder piece. I also screwed on top of all this a plastic clipboard, using long screws, some nuts and washers. This clipboard serves as the deck for the laptop. (I’m actually thinking of ditching this design in favor of a piece of sonotube, since it’d make it look nicer and might a bit better.)

And, while we’re at it, let’s throw a pan/tilt webcam on there. That way, we can look around with the robot. Logitech Orbit AF will do nicely:

Word of warning about the webcam: it was a pain in the butt to get the pan/tilt working with this thing. Something about the uvcvideo drivers in the newer kernel, blah blah blah. Bottom line? You need to compile and install libwebcam. You’ll get a little program called uvcdynctrl that will allow you to control pan/tilt, plus a bunch of other advanced controls. Until I’m ready to start posting the code up (it’s a mess at the momment: held together by digital duct tape) you’ll have to poke around the libwebcam forums and documentation.

So how about that? Some nice little upgrades there. Currently, I’ve been debugging and cleaning up the code, and since that means I have to teach myself Python, it’s taking a while. Feel free to take a look at all the crappy pictures I took while building it thus far…

crashbot

In case you’re wondering, i did the optional power step he describes. *THIS* is why I’m using the OLPC laptop for now: nothing else is this flexible with their power inputs. I can’t hook up anything else this easily. My eeepc 701 for example wants a nice clean 9.5 v at 2.5 amps. Not happenin’ (yet)…

The really important thing to note here is we have just potentially made our robot self-sufficient. The robot base AND the laptop can now dock with the docking station and recharge their batteries whenever they see fit. You could easily make the “low battery” warning trigger the dock-seek subroutine, set it up on a schedule, whatever. Point is: our robot can now (potentially) function indefinitely without the need of a human to refuel it. Obviously it can’t wander off too far, or it won’t make it back to the docking station, but hey, big step here.

Of course, there is a really big drawback here as well: the laptop will suck power from the robot constantly. Which means less battery life for the robot. We’ll fix that in our next step…

The other thing to note here is we now have some nifty software! It’s not perfect, but it’s better than VNCing into the laptop and some other craziness. Pretty basic for now, but we’ll upgrade that later. It’s made in Python, which means it’ll run on pretty much anything with a little tweaking. It also means it can run a tad slow, but for now it works. Much expansion here in the next step too…

So tune in next time, you damn kids with your music…

Oh wait, all I know about robots come from movies and TV. That might be a problem. Better start small and simple. Crawl before you walk before you run and so on. How’s about a simple as hell, darn-near idiot proof, ultra-n00b’s guide to building your first robot?

Hell, why not…

Turns out that robots, much like everything else, are nothing more than a carefully arranged pile of parts, held together by screws and software. So the question is: how “made from scratch” do you wanna go? If you’re really ambitious, you could go mine some copper ore, refine it into wire, build the motors yourself, and so on. I don’t know about you, but that ain’t happening…

You could buy some basic motors and wheels and bearing and all that junk, and build a robot up from the ground up. Maybe, someday. Not today…

How about we cheat a little? Let’s take a ready-built robot: the iRobot Create. It’s basically one of those robot vacuum cleaners, except without the vacuum cleaner.

Yay! We have a robot now! Let’s take over the world! Ok, well, not quite. It’s a robot by some measure of the word, but it doesn’t really do anything useful. Yet…

Here’s what it DOES do usefully: moves around based on serial commands, avoids obstacles, provides battery power from it’s 14.4v battery to anything you can wire into the cargo bay connector, and it can find it’s own charging station.

In fact you can pull it out of the box, slap in a battery, and hook the included cable up to the serial port of a computer, and drive the little robot with the computer!

Now imagine you have a laptop. If you don’t know how to do it by now, it’s pretty easy to connect to a laptop and remotely control it. You can use Remote Desktop Connection or VNC and control it like you were sitting right there if you wanted to keep it simple (and avoid writing code). Most laptops come with a webcam these days, and usb webcams are cheap. Laptops have wireless too…

…so duct tape the laptop to the robot!

You now have a self-mobile, remotely connectable, WiFi enabled robot with webcam and microphone. It can find it’s little charging station all by itself, and can avoid obstacles in some fashion. It even has a nice juicy screen to display stuff to people, and speakers to talk or play music with. It ain’t R2-D2, but you could easily use it as a remote surveillance / telepresence type thingie. Hostage negotiators could send one in to teleconference with the bad guys, while SWAT sneaks one in the back to map out the interior and looks around. In this case, it’s an OLPC XO laptop, which is nifty because of the swiveling screen, built in WiFi, webcam, microphone, and uber-long battery life. However, any laptop you have laying around can be used, but it seems like a cheap little netbook is particularly suited. I used the included iRobot cable and a cheap serial-to-usb converter to connect the robot to the laptop.

Now, granted, our robot still isn’t much to brag about. But if you didn’t get 100 ideas about how to IMPROVE on this little thing, you need to put down the internet and step away. Slowly.

That’s the beauty of this thing: it’s a simple yet marginally useful and functional platform to start with. Building a robot from scratch to this point is a long a frustrating process for beginners, and is usually the main barrier keeping them from really building anything. But now, we can focus on learning about the smaller and funner things. As time marches on, this little platform will become insufficient. By then, I’ll be ready to build one from scratch.

And there you have it. With about $400 and a bit of duct tape, you can “build” a somewhat useful robot! Don’t worry, more to come. Gotta make it cooler after all. Relatively soon.

And if this looks oddly familiar, it’s supposed to. I’m going to be building up his Fido robot (or as close as I can) as my personal starting point, and then tweak/hack/rebuild from there. I don’t want nobody thinking I’m stealing credit for this, give credit where credit is due and all that happiness. Updates during the process are the plan, but plans never survive first contact, so we’ll see when they get up.

and riboflavin…