Hackathon Results In The Facebook Book

July 30, 2012 by Mike Szczys 8 Comments

[Jeremy Blum] and [Jason Wright] pose with their project at the end of a 24 hour hackathon. The Facebook headquarters in New York City held the event as part of their Summer of Hack program. As an homage to the hosts, the hacking duo decided to create a physical book and populate it with the virtual Facebook. And what do you call such a creation? The Face(book)^2.

The video after the break gives the best overview of the hardware, but here’s the gist of it: They started with the largest hardcover book they could find, hollowing out its pages to house their own hardware. When you open the book it calls back to a computer over an Xbee link with a request for data. The python script on the computer pulls the newest from a Facebook feed, sending it back to the book to be displayed. There is a graphic LCD and four character LCDs built in for this purpose. There’s also an accelerometer which is used for detecting page turns when the cover is jostled. The rest of the interactivity is provided by a few tactile switches mounted next to the smaller LCD screens for navigation and the ‘like’ feature.

Continue reading “Hackathon Results In The Facebook Book” →

Mechanical Relay Logic That Was Snubbed For A Microcontroller

July 30, 2012 by Mike Szczys 27 Comments

[Alex] was tasked with a control design problem for a set of motors. The application called for the back of a truck to open up, some 3D scanning equipment to rise from its enclosure, and finally the equipment needed to rotate into place. All of this needed to happen with one flip of a switch, then proceed in reverse when the switch was turned off. We can understand why the final design used a microcontroller, but we also think that [Alex’s] relay logic circuit is an eloquent way of doing things.

He uses limiting switches as the feedback loop for the logic. In the video after the break he walks us through the schematic. Each of the three motors has an up and down limiting switch. These control the three relays which switch power to the motors. We like the design because interrupting the movement mid-operation provides no problem for the system. The only real issue we see is that relays wear out, and the automotive application of the hardware may cause this to happen more quickly than normal.

You may recognize the clear gears used in the demo. [Alex] previously showed us how he makes those.

Continue reading “Mechanical Relay Logic That Was Snubbed For A Microcontroller” →

Understanding Op-amps From Simple To Hard

July 30, 2012 by Mike Szczys 17 Comments

[Tim] wanted to help out a ECE student struggling with some Op-Amp problems. He put together a video which does a good job of explaining what an Op-Amp does, then tackles each of the questions one at a time.

His analogy is illustrated in this image. There’s an operator using a crane to lift a crate. He is watching a ‘radio man’ in a window of the building to know how high it should be lifted. These roles are translated to the function of an Op-Amp in a way that makes understanding the common parts quite easy. The crane is the Op-Amp and the floor to which it is trying to lift the crate is the input pin. The current height of the crate is the output signal. The radio man is the feedback resistor which is trying to get the desired height and current height to equal each other. Watch the video after the break and all becomes clear.

After this analogy is explained [Tim] tackles the actual homework problems. He’s going through everything pretty quickly, and doesn’t actually give the answers. What he does is show how this — like most circuit solving problems — depends on how you group the components in order to simplify the questions. Grab a pen and paper and put on your electron theory hats to see if you can solve the questions for yourselves.

Continue reading “Understanding Op-amps From Simple To Hard” →

Recovering From A Seagate HDD Firmware Bug

July 30, 2012 by Mike Szczys 41 Comments

Hard drive firmware is about the last place you want to find a bug. But that turned out to be the problem with [BBfoto’s] Seagate HDD which he was using in a RAID array. It stopped working completely, and he later found out the firmware has a bug that makes the drive think it’s permanently in a busy state. There’s a firmware upgrade available, but you have to apply it before the problem shows its face, otherwise you’re out of luck. Some searching led him to a hardware fix for the problem.

[Brad Garcia] put together the tutorial which illustrates the steps needed to unbrick the 7200.11 hard drive with the busy state bug. The image in the lower right shows the drive with a piece of paper between the PCB and the connectors which control the head. This is necessary to boot the drive without it hanging due to the bug. From there he issues serial commands to put it into Access Level 2, then removes the cardboard for the rest of the fix.

In the tutorial [Brad] uses a serial-TTL converter. [BBfoto] grabbed an Arduino instead, using it as a USB-ttl bridge.

Only You Can Kick A Child’s Balls Into Space

July 27, 2012 by Mike Szczys 26 Comments

We had a lot of fun with that title. Of course when you’re talking about launching a thousand ping pong balls into space there’s no end to the puns which can be made. But this is actually a fantastic initiative to get people of all ages excited about science and near-space experiments. [John Powell] offers school children the opportunity to send an experiment into space. He’s Kickstarting the next launch, which is scheduled to take place in September. This way each entrant can fly their project for free, then get the results and a certificate back once the weather-balloon-based hardware is recovered.

There is one size restriction for the program. Each experiment must fit inside of a ping pong ball. But you’ll be surprised what can be accomplished. [John] reports that the most simple, yet interesting project is to place a small marshmallow inside the ball. As it rises through the atmosphere it will grow to fill the entire ball, then be freeze-dried by the the extreme temperatures. Some are not so low-tech. There’s an image of a tiny PCB holding a DS1337 and some sensors. It’s an atmospheric data logger that will provide plenty of information to analyze upon its return.

[via Hacked Gadgets]

Decoding NOAA Weather Radio With An Arduino

July 27, 2012 by Mike Szczys 6 Comments

The National Oceanic and Atmospheric Administration is responsible for broadcasting the signals used in weather radios. They use a protocol called Specific Area Message Encoding (SAME) and [Ray Dees] recently published an Arduino library that lets you decode the SAME message packets.

He doesn’t provide a method of tuning the radio signal, but at first you can use the audio samples he points to. The actual broadcasts happen on one of seven frequencies between 162.400 MHz and 162.550 MHz but the tones are also broadcast on TV and Radio alerts. Once you have the audio it is fed into a pair of XR-2211 Tone decoders. This provides just three interface pins for the Arduino to watch.

The annoying noise that grabs your attention at the beginning of a weather alert, or test of the alert system is actually what the SAME data packets sound like. From those tones this system will be able to decode what type of alert is being issued, and the geographic locations it affects. If you interested in more info about SAME head over to the Wikipedia article on the topic.

Bending A Home Security Control Panel To Your Will

July 27, 2012 by Mike Szczys 35 Comments

Does your home have a security system but you don’t subscribe to the monitoring service to make it work? Rip that baby off of the wall and do something with it, or just build your own system around it. If you have a DSC PC1500RK control panel [CaitSith2] shows us how easy it is to control the buttons, LEDs, and buzzer. If you’ve got a different model this is still a good jumping off point to start your own reverse engineering.

There are only four connections that need to be made. [CaitSith2] is using an Arduino for the demonstration. He connected the red wire to voltage, the black wire to ground, the yellow wire (clock) to digital pin 3 and the green wire (data) to digital pin 2. A communication cycle starts by setting the data line high, then clocking out eight bits to capture keypresses. 16-bits are then clocked in to set the LEDs and drive the buzzer. This is shown in the video after the break as well as documented in his sample code. We’ve embedded the sketch after the break to preserve it in case the pastebin code goes missing in the future.

Continue reading “Bending A Home Security Control Panel To Your Will” →