[Patrick] decided to make a computer controlled etch-a-sketch. While the idea is not that new, there is always a different way to accomplish a goal. An Arduino is used to control a pair of stepper motors which were sourced for pretty cheap, and even came with their own driver. Next a stand was mocked up using foam board, which helps determine where all the parts should live.

Next was a way to attach the steppers to the knobs, gears would be used and a collet meant for model airplanes was sourced to make the mechanical connection between gear and shaft. With everything set in place via foam board and paper printouts, it is off to get some thin plywood. The plywood is sent though a laser cutter creating most of the stand and gears. Now its all software, a program was whipped up for OSX which converts low res pictures into squiggly lines perfect for the etch-a-sketch to draw on its screen.

The results are quite impressive, join us after the break for a quick video.

Even though we’ve seen dozens of Kinect hacks over the years, there are a few problems with the Kinect hardware itself. The range of the Kinect sensor starts at three feet, a fact not conducive to 3D scanner builds. Also, it’s not possible to connect more than one Kinect to a single computer – something that would lead to builds we can barely imagine right now.

Fear not, because Microsoft just released the Kinect for Windows. Basically, it’s designed expressly for hacking. The Kinect for Windows can reliably ‘see’ objects 40 cm (16 in) away, and supports up to four Kinects connected to the same computer.

Microsoft set the price of Kinect for Windows at $250. This is a deal breaker for us – a new Kinect for XBox sells for around half that. If you’re able to convince Microsoft you’re a student, the price of the Kinect for Windows comes down to $150. That’s not too shabby if you compare the price to that of a new XBox Kinect.

We expect most of the builders out there have already picked up a Kinect or two from their local Craigslist or Gamestop. If you haven’t (and have the all-important educational discount), this might be the one to buy.

Part of the fun with old computers is playing some old school games, and while you could play them with a keyboard it is much more fun with a joystick. You can get old joysticks all day long on auction sites, but you have to watch out. Some are digital, which wont work for many games on many systems. Some were cheap to begin with and probably worn out, and many are flight sticks … ever play pac-man with a giant flight stick?

What I really wanted was a game pad like device for my 1986 Apple //c , using one of the modern thumbstick analog controllers. Using a thumbstick out of an old XBOX(1) controller, some generic parts from Radio Shack, and a little bit of effort , I ended up with exactly what I wanted.

Join us after the break and I will show you how to get there!

First some basics, most computers that have analog controllers implement it in a pretty simple method. In a nutshell there is a 555 timer wired up for single shot mode, the computer triggers the 555 and counts how many cycles pass before the 555′s output changes. One of the potentiometers inside the joystick is hooked up to this circuit and controls the rate that a capacitor charges. Once filled the 555 changes output. Swing the joystick one way, resistance increases and the capacitor takes longer to charge. Swing it the other way resistance lowers, cap charges faster. Simple right?

Now just multiply 555′s for how many axis you need and you have a simple analog joystick. Apple //s, and IBMs work like this, and use a 556 dual timer (one, two axis joystick) or a 558 quad timer (two, two axis joysticks). Below is an example circuit from the Apple //c Technical Reference Manual.

Other computers like the 8 bit Commodore’s and Atari’s used this setup for their paddle controllers which were often in joystick or flightstick format. About the only one I know of that does not handle analog joysticks in this manner is the Tandy TRS series, but I am sure there are others. Check with your computers nerd club before proceeding.

Next thing to consider is the values of the potentiometers inside of your joystick. the most standard value for old computers is 100K ohm. Apple used 150K ohm. Why? I don’t know but with Apple stuff, if its hard to source, they will use it. Thumbsticks themselves come in all varieties of resistance, from places like Digikey. If you don’t mind spending a couple bucks + postage, that might be the best way for you.

Since I am using scavenged thumbstick from an XBOX controller I don’t have a choice of what value it is. The thumbsticks that come stock with that controller is 10K ohm. In order to compensate for the difference in resistance,we just need to add more capacitance.

Before I go bothering myself with math, I need to find out exactly where my joystick “tops out” while its in its enclosure. I went out an purchased a 4x2x1 inch enclosure from Radio Shack, and while I was there I also picked up a couple panel mount normally open pushbutton switches.

With these radio shack project boxes, they give 2 choices of a lid, a nice molded plastic lid that sits on top of the box, and an aluminum panel that sits a bit recessed in the box. I just had to have that aluminium panel for looks, but it ended up causing a bunch of problems.

First I had to cut the lip of the box off where the panel would not be recessed anymore. That was accomplished using some 90 degree flush cut wire trimmers and a file. Because I lost about a quarter of an inch in height, the thumbstick would not fit anymore using the screw mounts inside the box. I had to snap off the screw mounts, then flatten the area where they broke off with a chisel. Then I surface mounted everything to a piece of pad-per-hole perfboard flipped upside down, since the only way the thumbstick would fit is if the board was flat against the bottom.

With all of that sorted out, I went to drill holes into the aluminum panel. I drew the outline of the panel on some paper, and I was measuring everything out. I didn’t like how the holes were sitting, so in the end I just simply eyeballed them on paper. Then I taped the paper to the aluminum plate and made divots for the hole centers with a hammer and nail.

The aluminum plate was then screwed to a scrap chunk of 2×4 wood, and drilled. I used a 1 inch hole saw for the joystick (which is a bit too large) and quarter inch holes for the switches. I used a jewelers file to quickly deburr the holes, but the large joystick hole was still a little rough. To give a more finished appearance I decided that it needed a grommet.

I went to the local hardware store, and when I asked for a grommet with about a 1 inch inside diameter, they looked at me like I just stabbed a baby. I ended up at Lowes where I found a grommet in one of the “hard to find” bins in the screw section with a 1&1/8th outside diameter, and a 23/32nds inch (18.25 ish mm) inside diameter, which is good enough. The grommet was much too tall to fit both inside and outside of the box, so I just simply chopped its top off and glued it down with some goop (super strong and thick glue).

Now that the box is in order I can see where my thumbstick tops out at. I bent the leads of the thumbstick out to a 90 degree angle so I could surface mount them to the perfboard. Then I soldered it down and added some test leads, ran the wires out of a hole I drilled in the back of the box for the joysticks cable, and popped on the lid.

Using a multimeter I found out that it the furthest I could push the thumbstick came out to about 8.5K ohm on both axis. My meter is overkill for most of what I do, so I could have used the 5 digits of accuracy, but its not needed. I will add some trimpots later for fine tuning.

Now that I know 8.5K is my max resistance, its time to figure out how much capacitance I need to add so that the circuit internal to the computer will behave the same with this 10K pot as it did with a 150K. The formula to calculate the capacitance is pretty simple:

((original_potentiometer_value * internal_timing_capacitor) / new_potentiometer_value) – internal_timing_capacitor

Most of the time the internal timing capacitor is 0.022 uf, though you might want to check before assuming for your machine. The original potentiometer value of the Apple // is 150K ohm so…

((150,000 * 0.022) / 8500) – 0.022 = 0.366235294

Therefore we need to add about 0.36uf in parallel to the joystick so that a 10K pot works the same as a 150K pot in the timing circuit. My capacitor selection pretty much stinks so I ended up using 3, 0.1uf capacitors in parallel and 2, 0.1uf in series per axis, giving me about 0.35uf. It does not have to be exact because I also added a 10K trimpot in series with the capacitors which will allow me to control how fast the extra caps charge, giving a fine tuning mechanism. Below you will see the schematic I ended up with for my Apple //c.

Now it is just a matter of wiring everything up, connecting buttons and a cable, and then using a test program to calibrate the thumbstick. The Apple //c has a nice diagnostic program which also test’s joysticks, but you could just as easily write one up in basic. For example, in Applesoft:

10 X=PDL(0): FOR I=1 TO 10: NEXT: Y=PDL(1)
20 PRINT X " " Y " " PEEK(49249) , PEEK (49250)
30 GOTO 10

To calibrate I just need to adjust the trimpots until its about center, the program above shows value from 0-255, and we can give ourselves about 5% in error, from there its just a matter of making sure the thumbstick maxes the readouts when in its most extreme up/down/left/right positions. Some error is ok, and a little jitteryness in center is fine as well.

Anyone who has programmed for analog controllers quickly figure out a little dead space for middle and a little room for error on the extremes is needed whether it be a 26+ year old computer, or a brand new Sony PSP, nothing is 100% perfect.

Once the thumbstick is calibrated to the computer its time to button it up and play some retro games. How well does it work? Pretty darn good, I may go back and drill a couple small holes so I can fiddle with the trimpots without having to take it apart, but other than that it plays good and looks nice (IMO) .

Thanks for reading!

(Reference: The Computer Controller Cookbook)

[Nerdindustries] had a interesting idea; “what if you could just flip a switch and call someone?”. This happens a lot, especially in companies where your trying to catch a certain someone who is always swamped in phone calls. The Phone Box is a basic Nokia cellphone that has a number stored into its speed dial. To help aid in communication the phones output is directed to a three and a half watt amplifier module ensuring that your going to hear it.

A delay circuit was made out of a basic RC network, so when you hit the switch the phone has a chance to power up and fully boot. Once the delay triggers it presses the speed dial button and off you go. Now someone has already asked “Why don‘t you just call them?”, and we got a kick out of the first answer “calling someone is NOT nerdy.”

Join us after the break for a quick video.

In case you were asleep at the wheel, here are our top stories of the week.

Our most popular post was one that shows you how to make your own ‘personal assistant’ using Wolfram Alpha, text to speech software, and the phone network. It still won’t get your coffee though. You’ll just have to do that yourself.

Coming in at second place was a post about how to use your Android camera phone as a Geiger counter. Of course, this hack will work with any device that uses a CMOS sensor to do its imaging but they have gone and wrapped it up into a nice app.

Do you have access to a laser cutter and a burning desire (pun intended) to make gears? In this post Alex makes some acrylic gears using an Epilog laser cutter.

When is our government going to get it through their heads that we don’t want the internet to be controlled by a small group of corporations? Probably when the lobbyists stop giving them money by the boat load to do just that… It seems like several times a year a bill comes through that would severely restrict the internet or would at least allow someone to shut down a website without any sort of due process. Luckily, groups like the EFF are paying attention and are well organized for getting the word out there. This post was our stand against the current bills that threaten our internet freedom.

Finally, on a lighter note, we have a post about how to do ultrasonic welding on the cheap using a ‘heat staker’ and a small drill press.

[Ladyada] has been working on FLORA, her wearable electronics platform, for a few months now. Even though it has just been announced the specs look much better than the previous queen of the hill, the Arduino LilyPad.

Going down the spec sheet for both the FLORA and the LilyPad, we see that FLORA has twice as much flash and SRAM as the LilyPad. The LilyPad has more options for I/O, but [Ladyada]‘s FLORA has the benefit of not using an ISP header for programming; FLORA is completely USB-compatable. FLORA is also about a quarter-inch in diameter smaller than the LilyPad, something to take into account when you’re going for a wearable project.

On top of Bluetooth, GPS, accelerometer, compass and other modules planned for FLORA ( it doesn’t look like they’re available yet, though), FLORA has USB HID support so it can operate as a USB keyboard, mouse, MIDI device, or connect to a cell phone. If you’ve ever wanted a keytar cardigan, this is the board for you.

Check out [Ladyada]‘s video demo of a LED-equipped fabric after the break.

It doesn’t take much imagination at all to see what a horrible effect this censorship could have on sites like Hackaday. Please do your part to stop internet censorship.

Imagine how many companies would rather us not share with you how our brilliant readers have hacked their hardware to do bigger and better things than they were sold to do. Sites like Hackaday would not survive this censorship.

Flashlights are so 20th Century. Be it the incandescent type that popped up very early on, or LED models with came around in the 90′s, there’s not much excitement to the devices. But [Sriranjan Rasakatla] is doing his best to change that. This is his WAY-GO Torch, an intelligent flashlight (a Smart Light?) that will not just light your path, but overlay useful data on it.

At the front of the unit a pico projector is housed on a jointed assembly. This allows the device to project data on the ground in front of you. Using a digital compass and GPS module, it can show the polar coordinates, guide you on your way, or provide information about the buildings around you. The motorized mount provides image stabilization based on IMU data. Check out the demonstration video after the break. It shows general functionality in the first part of the clip, with some footage of the stabilization system at about 4:30.

This really does seem like it came right out of a Sci-Fi novel. It’s useful, but the complexity makes it surprising that [Sriranjan] was able to pull it off. We wonder how the battery life is on the device, but it can’t be any worse that one of those really huge flashlight builds.

For those of you who haven’t been paying attention in class, here is the best of what has hit our blog this past week:

In the #1 spot is a post about a project where some pretty ambitious hackers found a way to run Linux on a digital picture frame. Bravo!

Next up is a post where [Chris] needs some help getting his 1/10th scale, cycle accurate Cray I ‘supercomputer’ to boot.

In third place is a post about a very elaborate 737 cockpit simulator that was built over the past couple of years. This is a pretty intense build with lots of details about how it was done.

Following that is a post about a 3D-printed device that is similar to a phenakistoscope but instead of using slits to allow you to see the models in succession, it blinks some LEDs at the appropriate times.

Finally rounding things out in fifth place is a post about Makerbot Industries’ most recent release, which will let you print out your own phenakistoscope. This 3D printer is bigger than their makerbot and optionally sports two extruders instead of one so that you can do dual colors or possibly dual materials.

[John Zitterkopf] is in the middle of restoring a vintage Sega Star Trek Captain’s Chair arcade game for the upcoming 2012 Texas Pinball festival, though one prerequisite for the show is that the game supports some sort of free play mode. At this point he doesn’t have the option of tracking down a freeplay ROM for the device, so he had to come up with a solution of his own.

He did not want to alter the machine’s operation in any significant manner, and this meant preserving the functionality of the coin chutes. To do this, he put together a small circuit that uses a pair of cascaded 555 timers to provide the machine with the proper signaling to simulate coin insertion, while still accepting coins. You might initially think that this could be easily accomplished by shorting a pair of contacts in the coin chutes, but as [John] explains, the process is a tad more complex than that.

If you have some old arcade games kicking around and are looking for a non-invasive way to make them free to play, be sure to check out his site for schematics and a complete BoM.

[Thomas Renck] recently picked up a 1000mW wireless video transmitter that he ultimately planned to mount in an RC plane. Before he strapped it on a plane to potentially kiss it goodbye for good, he wanted to play with it a while to see what it was capable of.

After a friend helped him determine the camera’s maximum range (about 1900 feet on open ground), he thought it would be fun to strap it on his nitro R/C truck. That didn’t work out so well due to some vibration issues, so he constructed a makeshift R/C car from the shipping box the camera arrived in, along with some other odds and ends.

As you can see in the video below, the propeller-driven “Boxmobile” zips along quite nicely. The video feed from the camera is pretty impressive too, allowing him to easily guide the car while it’s well out of sight.

At nearly $350, the self-proclaimed “ghetto-bot” is certainly not cheap, though we hear body repairs are a piece of cake!

[Eric Gregori] recently spent some time messing around with a Hexbug Spider, and wrote in to share some modifications he made to the toy. In its unaltered form the robot can be controlled remotely, and while it’s fun to play with, the excitement is short lived. Using a TI MSP430 along with a small motor controller kit he put together, he gave the Hexbug a bit more personality.

The kit is really just a simple board used for mounting the MSP430 and FAN8200 motor driver, along with an IR emitter/sensor pair. It would be easy enough to put something similar together yourself, though if you are looking for a protoboard/deadbug/PCB etching-free solution, his Spider Hack kit is a quick and easy solution.

[Eric’s] walkthrough shows how to disassemble the Hexbug, and details which components need alterations before the controller board can be properly mounted. A few soldered wires later, the toy is ready to be reprogrammed, a process [Eric] carries out using the Launchpad board from which he lifted the MSP430.

As you can see in the videos below, calling the robot autonomous might be a bit of a stretch (I don’t see it walking to the kitchen to make me a sandwich), but it can navigate and avoid objects with ease.

[Rob Spanton’s] house is equipped with a rather cheap oven, which was discovered while his roommate tried using it to bake part of a wedding cake. If someone took a shower during the baking process, a large portion of unit’s gas pressure was diverted to the boiler, causing the oven to shut off completely. This is obviously not a good situation for baking cakes, so the housemates decided to construct a makeshift controller to keep temperatures in line.

They started by installing a pulley on the oven’s knob, which is connected to a small motor via a long rubber belt. The other end of the belt connects to a small motor, which is controlled by a Pololu 18v7 motor controller. A K-type thermocouple monitors the oven’s temp, feeding the data through a MAX6675 converter to (presumably) [Rob's] computer.

Since they were in a bit of a time crunch, [Rob] and his roommate [Johannes] decided the best way to keep the oven at a steady temperature was via bang-bang control. While you might imagine that cranking the gas knob between its minimum and maximum settings repeatedly wouldn’t be the ideal way to go about things, their solution worked pretty well. The cake came out perfectly, and the maximum temperature swing throughout the entire baking process was only 11.5°C – which is pretty reasonable considering the setup.

[Ian Cole’s] son is learning to play the drums on an electronic drum set, and he wanted a way to continue practicing during his frequent visits to his grandparents’ house. [Ian] had picked up a Spikenzielabs “Drum Kit Kit All-Inclusive” (DKKAI) earlier this summer, and set out to build an easily transportable drum set.

The DKKAI comes with an ATmega168-based board and a set of piezos that can be used to register hits. It was up to [Ian] to provide the rest of the kit, so he set off to IKEA in search of cheap, durable drum heads. He returned with a handful of 1/2 Liter plastic bowls, which he mounted on a PVC pipe drum stand.

The piezos were mounted on thin aluminum discs, which were in turn glued to the back side of the bowl lids. The piezos were wired to the DKKAI kit via the PVC tubing, with the signals ultimately fed into an iPad running Garage Band. [Ian] says that his portable drum set works quite well, and although there are some things that require changing, his son is very happy with his new practice set.

Check out the video below to see the portable drum kit in action.

Hackaday regular [Mikey Sklar] is no stranger to body modifications. He enjoys tweaking his body in ways that help him with day to day tasks, including a ruler tattoo on his arm and an RFID chip embedded in the web of his hand. Lately, he has been toying around with a less invasive means of getting a better feel for magnetic fields in his surroundings.

Turned on to magnetic rings by a friend, he now wears an epoxy-coated rare earth ring every day, changing the way he interacts with the world. He says that besides the obvious ability to tell when he’s near iron-heavy material, he can also feel cell phone calls, as the speaker draws the ring closer while producing sound.

He says that holding the electric cord of his tea kettle gave him the biggest start, making him feel as if he had been electrocuted, minus the actual shock.

While it’s not the most high-tech hack, [Mikey] is quite happy with the “sixth sense” this reasonably price ring has been able to provide – we just might have to try it out ourselves.