[Michael Kleinigger] posted a lengthy discussion on Pulse-Width Modulation that goes beyond the traditional beginner tutorial. He starts a bit of background info on PWM and a tip about using a camera to judge frequency and duty cycle of LEDs. From there it’s down the rabbit hole with some testing of power-loss versus frequency.

When you change from frequencies of 50 Hz to 1 MHz how does the parasitic power loss from switching affect the overall efficiency of the circuit? It turns out there’s a rather large amount of loss at the highest level, around 1.5 mW. The greatest balance of low power loss and elimination of flicker seems to be right in the 300-500 Hz range.

[Dodgy] wrote in to talk about his power meter data harvesting programs. This uses the same hardware by CurrentCost as the hack we looked at over the weekend but [Dodgy's] implementation is different. It’s separated into two parts, the first is a webserver written in C that harvests the data and makes it available at an address on the network, the second is written in Perl to format and upload data to Google PowerMeter.

The C program serves data on a configurable port, defaulting to 3090. All of the data can be accessed in one line of code by loading http://127.0.0.1:3090, or individually with subdirectories like /watts, /time, or /tempr. From there you can do what you want with the data. The second part of [Dodgy's] suite is a Perl script that polls the C server and sends the data to your Google account.

One thing that interests us is his comment that you should be able to compile the server side C code for an embedded device. It would be a nice energy savings to be able to upload data regularly without a PC running constantly.

This is what happens when [Mitch Altman] comes together with hackerspaces nationwide to have a contest. In short, 5 hackerspaces  will “take on the machine” and come up with 5 original ideas for existing devices. There are a few more rules, but you can catch them in the video in the link above. There is hinting at a slot machine that mixes drinks, a bike that makes ice cream, and more. What do you guys think is in store?

This is also a great opportunity to mention the hackerspaces wiki, find a community (or start one!) near you today and maybe [Mitch] will call on your hackerspace next competition. For now, we’ll keep you up to date with each hackerspace’s project and progress.

[Thanks Deven]

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No, the picture above is not a store made steadicam. Rather, a CNC machined one by [Matt]. Interestingly, unlike most steadicams we’ve seen before the gimbal is not the main focus of the design though an aluminum machined gimbal would make us drool. The central idea is allowing for X and Y axis adjustment to get oddly weighted bulky camera’s exact center of gravity. [Matt's] steadicam is also designed to handle more weight than commercial versions, and (if you already have a CNC) to be much cheaper. There’s no video, but from the skill of craftsmanship we can safely assume it’s as good and level as some of the best.

Halloween is rapidly approaching. This is just a reminder to you all to send in your Halloween hacks now so that we can all see them and steal your ideas get inspiration for our own projects. We’ve seen fantastic stuff in the past from motorized pumpkins to costumes that are simply awe-inspiring. Take a few moments to dig through the Halloween hacks we’ve run in the past.

Of course we understand that some of you will be pushing up to the big day to complete your projects. Just remember to take good pictures and document it all well.

[Dan Roe] has been working on Sculptural Robotics for quite some time, and most recently presented his newest creation: Solar Flowers 2010. Typically, Sculptural Robotics (coined by [Dan] himself) are stand alone, static art presentations made from electronic components and wire. [Dan] of course has taken it quite a bit further; giving all his sculptures life using solar panels, motors, engine circuits, and more. Making them zero emission, and beautiful at the same time. You can catch four videos after the jump of his moving sculptures. Not that we’re picking favorites, but the dragonfly is pretty amazing if we do say so ourselves.

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We love hacks that take quality products and make them better. This enhanced firmware for the VCI-100 is a great example of that. In a similar fashion as the Behringer hack, [DaveX] reverse engineer the firmware for the device and figured out a few ways to make it better. It improves the scratch controller and slider accuracy to use 9-bit accuracy from the ADC readings, which in the stock version were being shifted down to 7-bits. There’s also a few LED tricks they call Disco Mode. They’re selling a “chip” that you need to flash the firmware but from what we can see it’s simply an RS232 converter so you might be able to figure out how to work without that part. We’ve embedded a demo of firmware version 1.4 after the break.

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Want to see what’s behind you when riding your sport bike without taking your eyes off the road? They make rear view cameras for that but [Nescioqd] wanted a rear display right in his helmet (PDF). He started by mounting a rear-pointing camera on the back of the bike, powered from the 12V feed for the taillight. On the display side of things he picked up a Myvu Crystal wearable display. This is like a pair of glasses that have small LCD screens were the lenses should be. [Nescioqd] removed one lens and mounted it inside the helmet.

Since the display resides inside the helmet there is some concern about being able to see at night with a bright screen below your eyeball. [Nescioqd] actually ran into the opposite problem at first, bright sunlight makes it difficult to see the image on the LCD screen. He fixed this by picking up a dark tinted helmet visor (the easiest solution) but we’d love to see a photoresistor used to regulate the backlight level.

It would be interesting to see both screens used, with rear-view on one side and an instrument display on the other.