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MakerFaire North Carolina, We’ll see you there!

This weekend, June 16th, the North Carolina Maker Faire will be happening. This is the 3rd year for this event and from what we’ve seen in the past, it should be pretty good.

We realize that every site has its niche of event coverage that they should deliver. Engadget/Gizmodo need to show new phones and got to big apple announcements. Joystiq needs to be at E3. We feel like we should be where people are hacking/building things. In an effort to reach those places, Maker Faire pops into mind pretty quickly. [Jeremy Cook] will be at this one walking around and doing interviews as well as having a booth for his personal site jcopro.net . If you see him, don’t hesitate to go up and say hi, maybe he’ll have a custom cut vinyl hackaday sticker left to give out.

We plan on hitting as many other similar events as we can swing (sorry, looks like no one can make it to toorcamp this year). Our writers are located all over the country so if you hear of an event you think we would enjoy, shoot us an email. Maybe we can attend!

MITx 6.002x wraps up; here’s a review from one of the students

[Jorge] just finished MITx 6.002x with the fine score of 99.1%. Congratulations! We just finished reading through this review of his experience (translate) with the 14-week class and it sounds like the program is extremely well executed. For those that don’t remember, this is an intro to circuits and electronics course offered at the Massachusetts Institute of Technology. Except 6.002x is free to all as an online course (but if you actually want a certificate a fee may be involved).

Above is one of the many screenshots which [Jorge] took of the student web interface. It looks great, and offers pretty much everything you need to complete the class. The textbook, which runs at least $65 for a paper copy, is available through the web interface as part of the course. The labs even include web demos you can use to simulate circuits and probe and measure the resulting signals and wave forms. If you have questions there is access to the teachers, but also a set of forums where you can work with other students.

Perhaps most interesting is [Jorge's] assessment of the time you will spend working on the class. He thinks that if you’re already familiar with electronics the work can be complete in about one afternoon per week. Scheduling is flexible — tests are available for one week, but once you start taking one it must be completed in 24 hours.

He believes this will be offered again in the fall so keep a look out for registration to begin.

[Thanks Pan]

The effect of code on power consumption

Of course putting a microcontroller into sleep mode or changing the clock rate has an effect on the power consumption of the chip, but what about different bits of code? Is multiplying two numbers more efficient than adding them, and does ORing two values consume more power than NOPping? [jcw] wanted to compare the power draw of a microcontroller running different loops, so he threw some code on a JeeNode and hooked it up to an oscilloscope.

For his test, [jcw] tested two instructions: multiply and shift left. These loops run 50,000 and 5,000 times, respectively (bit shifting is really slow on ATMegas, apparently) and looked at the oscilloscope as the JeeNode was doing its work.

Surprisingly, there is a difference in power consumption between the multiply and shift loops. The shift loop draws 8.4 mA, while the multiply loop draws 8.8 mA. Not much, but clearly visible and measurable. While you’re probably not going to optimize the power draw of a project by only using low-power instructions, it’s still very interesting to watch a microcontroller do its thing.

Hands on with Raspbmc

Have you heard of the Raspberry Pi? Surprisingly enough, they’re starting to trickle into the hands of thousands of hackers, and we were fortunate to get our hands on one (second-hand since we didn’t jump in time for the initial preorder). We’ve longed for a tiny embedded option for running XBMC and this is one of the best opportunities we’ve seen yet. The Raspbmc project, created by [Sam Nazarko],  is tailored to getting XBMC on the Raspberry Pi just a few minutes after it arrives in the mail. And that’s exactly what we did.

If you’re familiar with writing an image to an SD card (or any device for that matter) this is a simple process. Raspbmc is distributed as a single image file which starts up the RPi hardware, then copies itself to RAM while it downloads and installs the filesystem for the distribution. Once the card is flashed just pop it in, power up, and wait about 20 minutes until XBMC shows up on the screen. After that it’s a quick boot each time.

The good news is that its works. XBMC runs pretty fast, with just a hint of lag when loading some menus. We felt at home using the confluence skin we’re familiar with, and had no trouble setting up our samba shares to the video library. The one problem is that it won’t play any of the video files we have on hand. None of them. So we downloaded the Big Buck Bunny trailer. It wouldn’t play that either. This is all a codec issue. Although the chip used on the RPi is capable of hardware decoding MPEG2 video, the foundation didn’t license that ability. So it can’t play that format, period. With the movie trailer we tried the OGG format and that’s not currently supported, but the MOV version did play, in full 1080p without trouble.

So the verdict is, if you’re looking to get an RPi just to run XBMC you should wait. So far the package is promising. But we record ATSC video, all of which is MPEG2. If you use MakeMKV to store your DVDs on a server, that also uses MPEG2. Of course there is the option of transcoding everything. But you’ll want to be careful if you have other XBMC frontends which may not be able to play alternative encodings.

Counting bees

This is the bee counter which [Hydronics] designed. It’s made to attach to the opening for a hive, and will count the number of bees entering and exiting. We’re not experienced bee keepers ourselves (in fact we’re more of the mind of getting rid of stinging beasties) but we understand their important role in agriculture and ecosystem so we’re glad someone’s making a nice home for them.

Most of the apparatus is a circuit board lined with reflective sensors. There is a double-row of pin sockets on the top of the board which accepts the Teensy+ which monitors those sensors. The bees must pass below this PCB every time they enter or leave the hive, thereby tripping a sensor. In the video after the break [Hydronics] shows off the system with a netbook used to monitor the output. But it sounds like he has plans for an integrated display system in future versions of the bee counter.

[Read more...]

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