A new beta build of VirtualBox, Sun’s Oracle’s free x86 virtualization software, makes it possible to run Mac OS X as a guest operating system…no shenanigans or flaming hoops to jump through, just pop in the $30 retail Snow Leopard upgrade disc and go. This had previously only been possible with some awkward Hackintosh-style maneuvering, or using recent editions of commercial virtualization products.
[William Etter] and his classmates built a quadcopter as a class project. We love the details of these builds and they came through with some thorough documentation. Some highlights that we enjoyed were reading about ABS body design and construction, their analysis of two versus three blade propellers, and their breadboarded control mechanism. You can see their success in the most recent post, but we all know that trial and error plays a role in these builds so we’re glad they’ve shared a collection of crashes with us.
Can’t get enough of this four-rotor action? Check out this project of a similar design.
Challenged by hot days and steep turf [Grayson Sigler] modified his reel mower to use electric motors. The end product will be radio controlled but he lacked the necessary parts to make it wireless right now. Not to be deterred, he used a wired controller for prototyping and testing that should be easily replaced once the parts arrive. Sadly, the grade of his yard causes the small wheels to slip so he tried inserting screws into the tread for added traction. The small mower lacks the weight and footprint that the Lawnbot400 enjoys. That being said, solar charging is one of the future goals so this build, which he named RoMOW, wins out on the green scale. We’ve included the prototype video after the break that shows the blades spinning away.
If you’re curious about tube amps but don’t have a firm enough knowledge base to dive right in you might want to try a kit. [Mark Houston] reviewed one such kit and we enjoyed reading about his experiences. It comes with everything you need save soldering tools, an enclosure, and the final connectors ([Mark] used RCA connectors). There is a full schematic available and the assembly instructions take you through tube matching and using that piece of copper coil you see in the picture to wind your own inductor. Consider trying this primer before you jump into building a single tube, multiple tube, or an amplifier of your own design.
[Thanks Gio]
[Meseta] built a powerful boost charger to top off his portable devices. He was inspired by the Minty Boost but wanted to overcome the rather limited capacity provided by the two-celled product. He ended up building his own DC to DC boost circuit rather than using an all-in-one IC. As you can see, the result uses four 18650 lithium-ion cells, normally found in laptop batteries, and can power two USB devices at the same time.
This pulse oximeter turned out very nicely. It is based around a Freescale microcontroller and detects pulse as well as oxygen saturation in your blood. The sensor is made of two wood pieces and allows two wavelengths of light to be shined through your finger. A sensor picks up the light on the other side of your stubby digit and the readings are compared to calculate saturation. Check out the finished project after the break.
We saw an Arduino-based oximeter a few months ago. These kind biometric hacks are rare around here. If you’ve got a well documented project don’t forget to tell us about it.
[Muris] is pumping out the home lighting hacks. He developed this motion sensing module as an add-on to the IR switch we saw last week. There’s some kind of fuse box above his entry door and its white cover, which you see above, is where he mounted an IR distance sensor to detect movement and switch on the lights. The RC5 infrared protocol is used to transmit the necessary signal to turn the lights on, then when a set amount of time has passed it will turn them back off again.
