Data Broacasting “Transparency Grenade” Ads Whimsy To Your Meetings

February 21, 2012 by Mike Szczys 11 Comments

If you’re tired of underhanded deals going down behind closed doors maybe you need to start carrying around this transparency grenade. The enclosure is modeled after a Soviet-era F1 Hand Grenade. But it’s not filled with explosives and won’t send deadly shrapnel around the room. Instead, when the pin is pulled it starts recording audio and sniffing network packets, then broadcasts both to a remote server. Perhaps you could consider this to be data shrapnel sent around the world.

The exploded parts image above shows what hardware is at use. There’s a Gumstix board at the heart of the device which uses a WiFi module for sniffing and broadcasting data. The LED bar graph which you see in the fully assembled unit shows the wireless signal strength.

It sounds like the enclosure itself was 3D printed from Tusk2700T translucent resin but we’re a little confused by this part of the hardware description. We don’t have much of a need to transmit recordings of our meetings, but we’d love to use this case design for that MP3 enclosure.

[via Reddit]

Wedding Gift Fail Has Happy Couple Cursing Your Name

February 17, 2012 by Mike Szczys 41 Comments

[Superluminal] received an invite to his friend’s wedding. He got together with some mutual acquaintances to take up a collection as a wedding gift. But as things go, a suitable present couldn’t be found. The pooled money itself ended up being the gift, but apparently a greeting card with a money pocket inside of it wasn’t good enough. The group decided to encase the coinage in a block of sugar that doubles as a lamp.

Now as with many well-meaning projects this started out with a rendering of what the final product would look like. That image came out great, with a high-gloss dark amber cube lit from the bottom with the coins suspended throughout catching a bit of a glint. They bought 43kg (almost 100 pounds) of refined sugar, and made a base/mold combination out of sheet metal. A lot of induction cooking went into producing thick syrup that could be poured into the mold. The problem is the final product is basically opaque. Not a sign of the 300 Euros within.

But don’t feel too bad for the groom and his bride. The image above shows him trying to get at the prize. He must do some hacking himself because he has a pressure washer, jack hammer (or is that big drill?), humongous cold chisel, and sizable hatch already at his disposal.

We can’t help but wonder if a heat gun could have polished the sides of the cube and helped add translucence?

Intro To Phase-Locked Loops

February 15, 2012 by Mike Szczys 18 Comments

[Kenneth Finnegan] put up a lengthy primer on PLLs (Phase-Locked Loops). We really enjoyed his presentation (even the part where he panders to Rigol for a free scope… sign us up for one of those too). The concepts behind a PLL are not hard to understand, and [Kenneth] managed to come up with a handful of different demonstrations that really help to drive each point home.

A PLL is made up of three parts: a phase detector, a low pass filter, and a voltage controlled oscillator. It can do really neat things, like multiply clock speed (you see them in beefier chips like the ARM architecture all the time). The experiments seen in the video use a CD4046 chip which has two different types of phase detectors. The two signals displayed on the oscilloscope above compare the incoming clock signal with the output from the VCO. Depending on the type of phase detector used, and the quality of the low-pass filter, these might be tightly synchronized or wildly unstable. Find out why by watching the video embedded after the break.

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Improving Your Flight Sim Experience With Hall Effect Sensors

February 14, 2012 by Mike Nathan 26 Comments

hall-effect-controls

[Gene Buckle] built himself a nice custom cockpit for playing Flight Simulator, but during use he found that the gimbal he constructed for the pitch and roll controls was nearly unusable. He narrowed the problem down to the potentiometers he used to read the angle of the controls, so he set off to find a suitable and more stable replacement.

He figured that Hall effect sensors would be perfect for the job, so he picked up a pair of Allegro 1302 sensors and began fabricating his new control inputs. He mounted a small section of a pen into a bearing to use as an input shaft, attaching a small neodymium magnet to either side. Since he wanted to use these as a drop-in replacement for the pots, he had to fabricate a set of control arms to fit on the pen segments before installing them into his cockpit.

Once everything was set, he fired up his computer and started the Windows joystick calibration tool. His potentiometer-based controls used to show a constant jitter of +/- 200-400 at center, but now the utility displays a steady “0”. We consider that a pretty good result!

[Thanks, Keith]

Passive Filters, Data Transmission And Equalization Oh My!

February 13, 2012 by Kevin Dady 17 Comments

[Shahriar] is back with a new “The Signal Path” video. It has been a few months but it is okay because his videos are always packed full of good information. Some new equipment has been added to his lab and as an added bonus a quick tour of the equipment is included at the start, which is great if you like drooling over sweet machines.

The real focus of the video is high speed data communications, getting up into the GHz per second range. [Shahriar] covers filtering techniques from simple RC low pass filters to pretty complex microwave filters. Explaining frequency and time domain measurements of a 1.5Gbps signal through a low bandwidth channel. He also shows how equalization can be used to overcome low bandwidth limitations.

It is an hour long video jam packed with information, so you might want to set aside some time and have a pencil on hand before going in. It is well worth it though, so join us after the break.

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Puncher Tracks Your Freelancing Hours, Time Spent In TSA Patdowns

February 12, 2012 by Mike Nathan 30 Comments

[Raphael Abrams] does a lot of freelance work, but he has trouble accurately keeping track of the hours he has put in for his clients. After trying various applications and methods of logging his time, he finally decided to build a device that worked just the way he liked.

He calls his device the “Freelance Puncher”, though it already has been nicknamed the detonator, as it looks like something you would find in the hands of a [James Bond] villain. The device uses a PIC16LF1827 to track the time, saving his logged hours to the built-in EEPROM when powered off. A pair of 7-segment displays are used to display the accumulated hours upon power-on, and a set of seven SMT LEDs separated into two banks keep track of quarter and hundreds of hours worked.

[Raphael] has made his code and schematics available on Github, so you can easily replicate his work if you are looking for a better way to track your time. We think it looks great, though it could be the sort of thing that traveling freelancers might want to keep in their checked luggage, unless they want to spend some quality time with the TSA! Be sure to stick around to see a short video where [Raphael] shows off and explains how his Freelance Puncher works.

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Cockroft-Walton Multiplier Can Output Positive Or Negative Voltage

February 10, 2012 by Mike Szczys 16 Comments

If you’ve already dipped your toes into high-voltage power supply pool you may be thirsty for a bit more knowledge. Here’s a neat illustration of how to build a voltage multiplier that can output a positive or negative supply. It is based on a design known as the Cockroft-Walton Multiplier. It’s the add-on housed in the plastic box seen in the image above. It uses diodes and capacitors in an orientation very common for generating high voltages. In fact, the same thing can be found in that high-voltage bulletin board. The place this differs is when it comes to connecting the multiplier to the PSU.

If you look closely you can see one red and one black banana plug jack poking out the end of the plastic container. There is also a pair of these on the other end. The multiplier has been designed so that reconfiguring the inputs and outputs changes how it works. Each jack has been labeled with one possible input and one output. Choose the desired output (DC+ or DC-) and then follow the labels for the rest of the connections.

What can you do with this setup? Check out the clip after the break that shows it powering a lifter.

Continue reading “Cockroft-Walton Multiplier Can Output Positive Or Negative Voltage” →