[Pascal Brisset’s] WXHMD is based on the tiny Gumstix Overo Fire computer-on-module which features a beefy, 3D-capable OMAP processor that runs Linux. The Gumstix is interfaced with a Vuzix VR920 head-mounted display that includes a three-axis accelerometer and compass. Tying these together is a custom video digital-to-analog converter board of [Pascal’s] own design, created using direct-to-PCB inkjet printing techniques. For less than $1,000 total in parts, the result is a spatially aware six ounce computer, with display and battery and all, that fits neatly over the bridge of one’s nose.
It’s a fantastic hack and a nicely documented project, though even the device’s creator himself questions whether having a pair of microwave transceivers and a LiPo battery strapped directly over one’s eyes and brain is such a good idea.
Today we’re going to take a look at writing scripts for the Greasemonkey add-on for Firefox. This add-on allows us to use JavaScript to make changes to the way webpages are displayed on our browser. These changes can only be seen by a copy of Firefox that is running a particular script. As an example, we’re going to write a script that adds a border to the banner image of each article on Hack a Day by overlaying the image you see above. Find out how it’s done after the break. Read the rest of this entry »
If you’re wanting to spice up a Jack-o-lantern, why not give it some spooky eyes that will look around? [todbot] shows us how to set this up using an Arduino and 3 servos. His rig uses a hobby servo to control the entire head’s orientation and a smaller servo for each eye’s movement. Their motion is random, but quite convincing. He has them all stuck together with popsicle sticks, but you would probably move the location of the large servo to rotate the entire pumpkin, or whatever other prop you put it all in. You can download the Arduino sketch and give it a try your self. We might suggest building a simple rack and pinion rig to rotate both eyeballs with a single servo.
[creatrope] sent in this slick Alien costume that he made for his son. The costume does look decent, but not professional. For something tossed together from parts around the house, it looks fantastic. The real kicker, is the fact that it has the retractable inner mouth. The retractable mechanism is constructed from Legos and extends when his son opens the mouth. We think he did a fantastic job with this costume, but if you’re looking for something a little more polished, check out this Alien made by [Asy0uw1sh ] you can see a little more detail on how it works here.
We’re not sure why [Roteno] prefers to have his TV and cable boxes not face him when he’s sitting on the couch, but to each their own. You may already see many problems with this setup: discoloration from LCD viewing angle, difficulty playing Wii, oh and most importantly – not being able to change the channel with his IR remote. [Roteno] was lucky enough, however, to have an IR remote input on the back of his cable box. All it took was a 3.5mm jack and a spare IR receiver and he was back in business. Sure it’s not as technical as some of our cable or IR hacks and we would like to see someone try this who doesn’t have as easily accessible IR input on the back of their cable box. But either way, here’s one more step to never having to leave that couch.
[Viacheslav] built a plotter that is fast and accurate. He wanted to take it one step further and added a laser in place of the pen. The 300 mW unit does a nice job of wood-burning any pattern sent to it, but isn’t strong enough to serve as a laser cutter for anything other than thin-film. We wonder if it can be used to cut solder paste stencils for surface mount PCB production.
In the video after the break you can see some plotting that uses a pen. In addition to writing on paper, [Viacheslav] has tested this as a method of applying etch resist to a copper clad board for PCB production. He’s able to achieve 0.8 mm pitch but the production process is limited by the resist pen’s tendency to wear out quickly and to only prevent etching for a short period of time (compared to toner transfer resist).
Just like with his touch sensitive keypad project, he’s taken the time to thoroughly document his work. Build notes, pictures, CAD files, and source code are all available for your perusal and hackage.
Above is a video detailing one method for populating a two sided surface mount PCB. We covered using a stencil to apply solder paste for a PCB a few weeks ago. In the comments there was a debate about the virtue of using stencils as well as a question about how two sided boards are populated. This was a good question because reflowing a board twice can cause components on the underside to fall off.
[Wim L's] comment mentions that there are a couple of methods for two sided population. In the video you will see that a stencil is not being used, but instead, paste is applied by a pedal actuated syringe. The paste is applied to the underside of the board first, then a teeny dot of epoxy is added to hold the component in place. Each part is then positioned normally and baked in a reflow oven. This process both reflows the solder, and cures the epoxy. When the board is reflowed a second time, the epoxy holds the bottom components in place as the top solder reaches its melting point.
This method of applying solder paste is slower than using a stencil. But if done correctly, every component can get the amount of solder needed.
[Richard] combined creative carving with vacuum tube electronics for a unique pumpkin offering. He used the stencil-and-cut method of carving, making use of an inexpensive carving kit for great results. He salvaged an LED module from a flashlight to provide the internal illumination, but it’s the center feature that we like the best. [Richard's] used a glow-transfer counting tube, or dekatron, which provides something like a circular cylon eye to the project. There’s a video of this after the break.
You might not have access to a wicked-looking dekatron but we’re guessing you’ve got a microcontroller and some LEDs lying around that can serve as a stand-in for one night. We’d love to do a reader jack-o-lantern roundup, so if you build something, send us a picture!
