Many of us here in the office (myself included) can’t tell the difference, but the audiophiles out there who want the best sound from their resistors should check out [Troel's] write-up for making your own non-inductive graphite resistors. Graphite resistors have the traits for being non-inductive, have a negative temperature coefficient, and supposedly sound better. We liked the detail of his tutorial and how he gives many examples for making your own graphite resistor.
[MS3FGX] has done an interesting study about using Bluetooth adapters as a source for Pseudorandom Number Generation (PRNG). As it turns out, the Bluez package has a function that calls a remote Bluetooth adapter to return a random number. He picked up 10 compatible adapters for about $30 from DealExtreme and set about assembling some numbers to see how this compares to an OS-based PRNG.
Because millions of samples are needed for an accurate comparison, time became a problem. The adapters are a little bit slow responding to a request, sending just 4800 numbers in the first 30-second test. This can be overcome with multiple adapters being accessed by multiple computers for hours at a time. What can this be used for? Your guess is as good as ours, but [MS3FGX] has done a great job of writing up his tests. He’s also made a set of 20.7 million randomly generated values available if you want to generate your own statistical analysis.
Being avid fanatics of flashing lights, we always love to see the peggy2 in action. The video above shows another improvement, which is two peggy2 units working together as one. [iservice2000] chained the two together and wrote new code for the display. Using an Arduino to drive it all, he has gotten them to act as one. While video on the peggy2 isn’t new, this is the first time we’ve seen two of them chained together. The end result is going to be a scrolling sign that can be updated via the web, or that can display tweets. We did notice a bit of tearing, is that from the camera or the software?
Yes, your eyes do not lie, that is 12 cameras rigged to take a picture at the exact same moment. The idea is a single camera loses data (namely depth) when it takes a 3D image and transposes it onto a 2D medium. FuturePicture somewhat circumvents this loss by taking several pictures with different focus distances. In short, the camera array allows you to focus on multiple items within a scene. The project’s hardware and software have yet to be released (we do know it’s at least Arduino), but they plan to make it entirely open source so everyone can experiment. Of course, we’ll keep you up to date.
[via Make]
We’ve spent some serious time building robot chassis and motor controllers. [Whamodyne] does the smart thing and scavenges what he needs form cheap sources. He picked up an RC car from the local pharmacy for just $10, tore the body off and behold, a bounty of robot-friendly parts.
We’re not talking precision parts here, but we don’t scoff at two geared motors, four wheels, a driver board, and steering. There’s no great way to attach your own stuff but that’s half the fun of hacking. [Whamodyne] used the 9v battery that came with the toy to power his boarduino and quickly patched in to produce a miracle of automated locomotion.
[Andrew] wanted a tablet computer but is tired of waiting for Apple to come up with one. eBay and Craig’s list to the rescue, he picked up some parts and built his own tablet. You can take a look at the video tour of it after the break, or peruse parts one, two, three, and four of his work log.
The unit is assembled from a 500 MHz iBook. [Andrew] picked up a touchscreen from ebay and canibalized a USB joystick in order to add some buttons to the keyboard-less design. The end product is quite nice. We’ve wanted a tablet computer to hang on the wall for a long time and this may be the inspiration that gets us there.
Do you find this didn’t satisfy your Apple tablet fix? There’s more to be seen in our mac tablets roundup.
Oh this one’s good! This clock has a built-in WWVB receiver to make sure the time is always accurate. But with just one LED as the display we wish you good luck when reading it! A whole bunch of info (time, day, year, etc) is blinked out in binary encoded decimal. [Thanks Tymm]
Standard Time
Manual labor. This clock is an art installation in Rotterdam. In the video you can see that workers changed the segments of a four-digit display every minute over a twenty-four hour period. Since they filmed it we’d expect the ability to turn this into a video clock like the one we saw last week. [Thanks David]
International Clock
Low-tech but highly creative. The instructional video uses basic geometry and the workings from a cheap clock to craft an international clock. There are twelve labels corresponding to different time zones. Put the zone you want up and read the clock as normal. [via Red Ferrett Journal]
Princess and the Pea
There are few who will agree to have an air tank as part of an alarm clock. The Princess and the Pea concept uses compressed air to inflate an exercise ball in between the mattress and the box spring. Watch this video to see how it will roll you out of bed if the hissing air sound didn’t wake you first. At least it’s more gentle than the pneumatic alarm clock from last June. [via Neatorama]
[Jarek] found a non-functional robotic arm sitting around and wanted to get it working again. By adding a few custom boards to an Arduino he managed to do just that.
The arm is driven by six stepper motors, each having four control wires. To handle all of these [Jarek] used TIP120 transistors to protect the controller. This still leaves the problem of 24 control wires to connect. By using a couple of 74HC4514 demultiplex chips he cut that number down to just 8 Arduino control pins. He completed the project by interfacing an original Playstation controller as the input device.
Source code for the project is available for download but we didn’t see a schematic for his setup. This shouldn’t be a problem as the low parts count should mean the datasheets for the transistors and demultiplexers are all you really need.
