Running The Numbers On A Cheap PSU

January 6, 2012 by Mike Szczys 22 Comments

[Mike] picked up a cheap USB hub for four pounds (about $6) including delivery. He wanted to know how it’s possible to get quality electronics for that price, and as you may have guessed it’s not possible. He cracked open the power supply that shipped with the hub and hooked it up for some testing.

The wall wart has a sticker on it that claims a rating of 1 Amp at 5 volts. It’s pretty easy to see that this hardware cannot meet that spec just by looking at the circuit board. It’s a low-end single sided board that has some really disappointing isolation between the mains and regulated side of the circuit. As far as we can tell there’s really no reliable regulation circuit on the low side of the transformer, and the tests that [Mike] runs in the clip after the break show this. From left to right in the picture above you can see voltage at the hub-side of the power cord, current on the load, and voltage leaving the circuit board. At just 560 mA the voltage the USB hub is receiving has fallen below 3 volts!

The link to this project was sent in by [Paul] after reading about that fake Canon camera PSU. We love this kind of stuff so keep the tips coming as you find them!

Continue reading “Running The Numbers On A Cheap PSU” →

Need A Hand Drying Those Gloves?

January 6, 2012 by Kevin Dady 23 Comments

While being caught out in the rain skiing, [Andrew] was left with a pair of soaking wet gloves. Leaving them to air dry did little good, as after 3 days they were still wet, and blowing a fan at them did little to nothing to help the situation. Luckily [Andrew] had been thinking about ways to make a forced air glove drier for some time now using standard plumbing fittings.

A prototype was made similar to consumer models where the glove is fit over the end of a pipe, and while this worked great to dry the palms, it did not help the wet finger situation at all. In order to solve this issue a new design was whipped up featuring 4 fixed fingers and a movable thumb made out of copper pipe. A little drilling, and soldering was performed then the metal hand was then duct taped to the end of a hair drier, turning soaked gloves into perfectly dry ones in about three hours.

Exposing Some Fake Electronics With Too-good-to-be-true Prices

January 4, 2012 by Mike Szczys 130 Comments

[Giorgos Lazaridis] needed an AC adaptor for his Canon PowerShot camera. He hit eBay and was excited to find this branded adaptor for just five bucks! It works and, even though it would sometimes reboot his camera if the cord was twisted around in the jack, he was satisfied that it did what it was supposed to.

That is, until one day he observed some very peculiar behavior while taking pictures of a PIC circuit he was prototyping. When holding the camera and putting his other hand near the breadboard one of the status LEDs in his circuit began flashing sporadically. If he was using the camera with batteries instead of the adapter this didn’t happen.

His first instinct was to hook up the adapter to his oscilloscope and see what is happening on the power bus. The signal is incredibly noisy. Shockingly so. [Giorgos] cracked open the case to see what is going on with the power supply circuit inside. You simply must view the video after the break to see the horror-show he found. The board is poorly soldered, components are not properly seated in their footprints, and our favorite is when [Giorgos] points out a squiggly trace which takes the place of the smoothing inductors.

Have you documented your own fake electronic hardware finds? We’d love to hear about them. Continue reading “Exposing Some Fake Electronics With Too-good-to-be-true Prices” →

Give Yourself A Sixth Sense On The Cheap

January 2, 2012 by Mike Nathan 71 Comments

sixth-sense-magnetic-ring

Hackaday regular [Mikey Sklar] is no stranger to body modifications. He enjoys tweaking his body in ways that help him with day to day tasks, including a ruler tattoo on his arm and an RFID chip embedded in the web of his hand. Lately, he has been toying around with a less invasive means of getting a better feel for magnetic fields in his surroundings.

Turned on to magnetic rings by a friend, he now wears an epoxy-coated rare earth ring every day, changing the way he interacts with the world. He says that besides the obvious ability to tell when he’s near iron-heavy material, he can also feel cell phone calls, as the speaker draws the ring closer while producing sound.

He says that holding the electric cord of his tea kettle gave him the biggest start, making him feel as if he had been electrocuted, minus the actual shock.

While it’s not the most high-tech hack, [Mikey] is quite happy with the “sixth sense” this reasonably price ring has been able to provide – we just might have to try it out ourselves.

[Bob] Shows Us How To Make DIY Calendars For Vintage Computer Geeks

December 29, 2011 by Mike Nathan 1 Comment

[Bob Alexander] wrote in to share a hobby of his that we thought was pretty timely considering the new year is quickly approaching. For several years now he has put together a custom calendar for himself, including both dates he finds important along with sweet pictures of vintage computer equipment. Friends and family found his calendars so intriguing that they asked him to make some for them as well.

Each year his stack of calendar requests grew, and he found that no outlet – online or otherwise could produce exactly what he wanted. Instead of settling, he wrote a small application that lets him customize and print calendars to his heart’s content.

We think this is much cooler than buying one at your local bookstore, and we’re guessing that our readers likely agree. If you were creating your own custom calendar, what cool vintage computer hardware would you choose to display? What if you were designing a Hack-a-Day calendar? Let us know in the comments – we’re itching to find something interesting to look at while we count down to New Year’s Eve!

DIY Solution Does PoE On The Cheap

December 24, 2011 by Mike Nathan 23 Comments

diy-poe

Depending on the scope of your requirements, Power over Ethernet (PoE) components can get pretty pricey. [Fire] wrote in to share a 4-port PoE solution he put together for under 20 euros (Ignore any SSL errors – we’ve checked it out, it’s safe).

The most expensive part of the build was the 8-port patch panel he purchased for 11 euros. He popped it open, wiring the first four ports for power after drilling spots for an indicator LED and the PSU. He wound the power lines through ferrite beads to hoping to dampen any interference that might occur before reassembling the panel.

In the picture above, you might notice that the panel is being powered via the first Ethernet port rather than through the barrel jack, which [Fire] said was done for testing purposes. When deployed in his network, he plans on using a regulated power supply from a junked laptop to provide electricity.

If you need to provide PoE to devices on your network, this is a great way to go about it. Using a patch panel like [Fire] has gives you the flexibility to easily wire up as many powered ports as you need without much hassle.

Make Any Scrap Of Paper Sticky With 2000 Volts

December 23, 2011 by Mike Szczys 22 Comments

Who needs chemistry when a little bit of physics will do? Instead of brewing up a batch of weak adhesive to make his own post-it notes, [Valentin] built this handheld device to add an electrostatic charge to bits of paper. Just give them a couple of seconds to charge and they’ll stick to the wall with ease.

The charging circuit is pretty simple, involving a transformer, transistor, resistor, and four diodes for rectification. He walks us through the build process, free forming the circuit using the transformer housing as a base. Once the circuit is fully assembled, a 9 volt battery connector is added and the fragile parts are hot-glued in place. It boosts the output voltage all the way up to 2 kV, but it’s still safe because it’s at a very low current.

The concept is akin to the high-voltage bulletin board seen last month. We wonder how long the notes will stay in place without an active electrical connection to keep the charge?