Hackaday Links: April 6, 2014

April 6, 2014 by 22 Comments

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Back in September we saw this awesomesauce wristwatch. Well, [Zak] is now kitting it up. Learn more about the current version, or order one. [Thanks Petr]

Home automation is from the future, right? Well at [boltzmann138’s] house it’s actually from The Next Generation. His home automation dashboard is based on the LCARS interface; he hit the mark perfectly! Anyone thinking what we’re thinking? This should be entered in the Hackaday Sci-Fi Contest, right? [via Adafruit]

PCB fab can vary greatly depending on board size, number of layers, number of copies, and turn time. PCBShopper will perform a meta-search and let you know what all of your options are. We ran a couple of tests and like what we saw. But we haven’t verified the information is all good so do leave a note about your own experience with the site in the comments below. [via Galactic Studios]

We recently mentioned our own woes about acquiring BeagleBone Black boards. It looks like an authorized clone board is poised to enter the market.

Speaking of the BBB, check out this wireless remote wireless sensor hack which [Chirag Nagpal] is interfacing with the BBB.

We haven’t tried to set up any long-range microwave communications systems. Neither has [Kenneth Finnegan] but that didn’t stop him from giving it a whirl. He’s using Nanobridge M5 hardware to help set up a system for a triathlon happening near him.

DIY Electricity And Internet For Burning Man

September 12, 2013 by 19 Comments

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Despite this being [Kenneth Finnegan’s] first Burning Man, the guy came prepared and stayed connected by setting up a beefy electricity supply and a faint yet functional internet connection. If you saw [Kenneth’s] Burning Man slideshow, you know that the desert is but a mild deterrent against power, water, and even temporary runways.

He borrowed a 20V 100W solar panel from Cal Poly and picked up a bargain-price TSMT-20A solar charge controller off eBay. The controller babysits the batteries by preventing both overcharging and over-discharging. The batteries—two Trojan-105 220Ah 6V behemoths—came limping out of a scissor lift on their last legs of life: a high internal resistance ruled out large current draws. Fortunately, the power demands were low, as the majority of devices were 12VDC or USB. [Kenneth] also had conveniently built this USB power strip earlier in the year, which he brought along to step down to 5VDC for USB charging.

Internet in the desert, however, was less reliable. A small team provides a microwave link from civilization every summer, which is shared via open access points in 3 different camps. [Kenneth] pointed his Ubiquiti NanoStation at the nearest one, which provided a host of inconvenient quirks and top speeds of 2-20kBps: enough, at least, to check emails.

Accelerometer Poi

September 12, 2013 by 15 Comments

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Even if you’ve never attended a rave, you have probably seen one portrayed on film or television. Those glowing spheres-on-a-string being swung around are called poi, and [Matt Keeter] has designed a pair with an accelerometer upgrade. Poi have a long history and were originally made from plants, but contemporary examples usually feature some kind of light, whether it’s fire, LEDs, or even glowsticks tied to shoelaces.

This build required double-sided PCBs and [Matt] had to custom make the protective covering that slips over the board. The poi are powered by 2 AA batteries fed into a 5V boost regulator. But wait, no microcontroller and no PWM? Actually, we think it’s quite clever that [Matt] took the output from the accelerometer and fed into an inverting amplifier. This keeps the voltage constant while allowing the accelerometer to vary the current. Had he used PWM, the fast motion of the swinging poi would instead produce a blinking effect.

An additional trimmer potentiometer accounts for variability in the accelerometers’ output by adjusting the default brightness. If the recent recap of Burning Man has you excitedly planning to attend next summer, you’d probably find plenty of opportunities to use these in the desert.

Build Your Own Dumb USB Power Strip

February 22, 2013 by 21 Comments

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Here’s a USB charging center which [Kenneth Finnegan] built using parts from his junk bin. We’d like to reiterate our claim that he must have the most magical of junk bins (the last thing we saw him pull out of it was a 24-port managed Ethernet switch).

The jack on the side accepts the barrel connector from a 12V wall wart. [Kenneth] mentions that the 2.1mm jack is a standard he uses in all of his projects. Inside there’s a switch mode power supply that provides the regulated 5V to each USB port. We really like the fact that he added some protection; diy is no fun if you end up frying your beloved multi-hundred dollar devices. The yellow components are polyfuses which will cut the power if 600 mA of current is exceeded. This works great for almost all of his devices, but his iPod 4G doesn’t like the system. It sees the voltage dip just a bit and stops charging entirely.

Cracking Open A 24-port Switch So You Don’t Have To

February 15, 2013 by 14 Comments

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[Kenneth Finnegan’s] post about this 24-Port HP ProCurve 2824 Ethernet Switch teardown was a delight to read. He’s taking an introduction to networking class at California Polytechnic State University. One of their labs included virtual machines shooting thousands of new MAC addresses at the thing all at once. Despite it’s ability to switch data at a blazing fast rate, it’s ability to deal with that many new hardware identifiers was less than impressive. He wanted to find out why and it just so happened he had one of these in his parts bin at home (which he refers to as if it’s a high-powered RPG character).

The mainboard is divided into three major blocks: the power supply, the switching hardware, and the processor that makes this a manged switch. Although he covers all of these pieces (and the switching stuff is very interesting to learn about) it is the processor section that was causing the aforementioned slowdown. It’s a 266MHz PowerPC chip with a measly 64 MB of RAM. Of course this doesn’t need to be any more powerful since all traffic from previously ‘learned’ MAC addresses gets handled by the switching block and never touches the processor portion.

Don’t miss the end of his post where he discusses how the filtering caps, and semi-isolated ground planes help to tame the beast created from all of this high-speed switching.

555-timer Charges Lead Acid Batteries

February 14, 2013 by 16 Comments

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[Kenneth Finnegan] took the focus of a great design and redirected it to solve his own problem. What results is this lead acid battery charger based on the 555 timer. It’s not a top-of-the-line, all the bells and whistles type of charger. But it gets the job done with a readily available IC and no need to code for a microcontroller.

The original idea came from a solar battery charger entered in the 555 timer contest. The main difference in application between that and [Kenneth’s] application is the source. A solar array or wind turbine is limited on how much juice it can produce. But mains power can push a shocking (har-har) amount of current if you’re not paying attention. Herein lies the alterations to the circuit design. To control this he’s using a Laptop power supply as an intermediary and only implementing the constant current portion of the tradition 3-stage lead acid charging profile (those stages are explained in his write up).

He did a talk on the charger at his local radio club. You can see the 90-minute video after the break.

Continue reading “555-timer Charges Lead Acid Batteries” →

Dot Matrix Printer Spits Out Any Tweet Mentioning @KWF

May 31, 2012 by 2 Comments

Earlier this month, [Kenneth] picked up an old dot matrix printer at the Silicon Valley Flea Market and subsequently found two cases of tractor feed printer paper. It’s a marriage made in heaven for a dot matrix twitter printer.

[Kenneth] used a BeagleBone – a tiny single board computer running Linux – to connect to the Internet and fetch any new tweets mentioning KWF every minute or so. The BeagleBone spits out these tweets over the USB port which is connected to the ancient printer by means of a cheap adapter cable.

Interestingly, [Kenneth] wrote the code for this project as a shell script. A lot of effort went into scrubbing the input of any escape characters, but he still implores his admirers to not attempt to break his project.

In case you’re wondering, at couple Twitter accounts announced this post’s headline to the Twitterverse when this story was published. This should have immediately sent [Kenneth]’s printer into motion, recording that harsh mistress that is sending a build log of a Twitter connected device into Hackaday.

After the break you can see [Kenneth]’s demo. Be sure to share this post on Twitter!