Serial port controlled CPU fan

[Christian] was running a Linux box as a home server but needed a way to quiet the noisy machine. Like many Linux servers, he’s using some pretty old hardware which doesn’t have an on-board header for the CPU fan which generates much of the unwanted sound. Those headers are nice because software can monitor the CPU and board temperature and adjust the fan accordingly.

[Christian’s] solution was to use the serial port for the task. He built a small circuit in which serial pin 3 drives the base of a transistor, pin 5 provides ground, and a floppy drive power cable supplies 5 volts. From there he wrote a RUBY program to monitor the CPU temperature and generate a PWM signal on the serial port, throttling the fan speed as needed.

[CC Photo Credit: Garrette via Flickr]

BAMF2010: Look sir, droids!

Ask any engineer what originally sparked their interest in technology, and almost universally the response will be a Hollywood film or TV robot — Star Wars’ R2-D2, the B9 robot from Lost in Space, or Short Circuit’s Johnny 5, to name a few. Engineers need a creative outlet too, and some pay homage to their inspirations by building elaborate reproductions. At this year’s Maker Faire, droid-builders had their own corner in the center hall, their work ranging from humble craft materials to ’bots surpassing their film counterparts in detail and workmanship.

Continue reading “BAMF2010: Look sir, droids!”

PWM fan controller for external hard drive

[Alan] noticed that his external hard drive was getting quite hot to the touch after a few hours. He says that it was probably designed to handle the heat sufficiently, he thought it would be fun to beef it up. He’s using a pic 12f675 microcontroller as the brain and an LM35 temperature sensor. The Fan speed is varried in 8 steps from 35 degrees C to 45 degrees C.

Fan-powered skateboard

[Chris Neal] is starting his hacking career young. He built this fan-powered skateboard for his fourth grade ‘Invention Convention’. The ideas were his own but he had some help with the construction from his uncle who owns a repair garage. On the back of the board there’s a motorcycle battery that powers the fan. We’re not sure where that fan came from, but apparently it can push a rider at about 3-5 MPH. [Chris] scored a free MacBook pro from this hack after being featured on the Ellen DeGeneres Show.

For some reason this sparks the memory of the drill powered minibike.

[via Gizmo Watch]

LED and fan controller

Needing a front fan to keep his hard drive cool, [CalcProgrammer1] found he was unhappy with a single LED color for the fan. He swapped them out for a set of four RGB LEDs and whipped up his own controller board for the unit. It is based around an ATmega168 and patches into the COM2 header on the motherboard, providing a serial interface. [CalcProgrammer1] wrote a GUI to control fan speed, and individual LED color settings. You can take a look at and enthralling, edge-of-your-seat demonstration of how slider controls work after the break. Wouldn’t it be great if the HDD LED clock could be adapted to use a fan so that the front panel had a colorful analog dial on it? Continue reading “LED and fan controller”

It has blades: Dyson’s little white lie


‘There’s a sucker born every minute” -P.T. Barnum

This morning we’ve been having a heated discussion at the Hack a Day offices (read: legion of doom) over Dyson’s new offering, a “bladeless fan”. At first this seemed extremely exciting, but how is the air being moved? We were hoping for a device operating via ionic wind but that’s simply not the case. Some of us think the bladeless claim is an outright lie, others understand it from a marketing stance, but we all agree: a fan with blades is still moving the air.

Dyson’s own information page states that “an energy efficient brushless motor” draws the air in with similar technology used in “superchargers and jet engines”, both of which use blades! The fan blades are in the base of this unit, they take in air and blow it out the ring. Just because you can’t see a fan, can we call our computers bladeless, or an air conditioner bladeless?

Enter the P.T. Barnum reference. Known as a man who could sell anything, his legacy lives on in the Dyson corporation. At 200 british pounds (~$320) for a ten inch desk fan, what are you getting that’s better than a traditional fan?  The design supposedly amplifies the air movement fifteen times, but we’re skeptical about that figure as there’s no energy-saving claim to go along with such an incredible power boost. One thing is certain, you will NOT get a fan without blades for your sterling… just one with hidden blades plus a huge marketing campaign.

[Thanks Gareth]

POV fan EEPROM hack


Hacking with Gum got their hands on one of the persistence of vision display fans that Cenzic was giving away at Blackhat this year. It’s not the biggest fan-based POV display we’ve seen but it’s still a fun device to tinker with. They hacked into the EEPROM on the device in order to change the message the fan displayed.

This is very similar to the other EEPROM reading/writing we’ve seen recently. Hacking with Gum read the data off of the EEPROM and then disassembled it to discover how the message data is stored on the chip. This was made easier by noting the messages displayed when the fan is running. The first byte of data shows the number of words in the message, then each chunk of word data is preceded by one byte that represents the number of letters in that work. Data length was calculated based on the number of pixels in each display character. Once he knew the data-storage scheme, it was just a matter of formatting his own messages in the same way and overwriting the chip.

This is a great write-up if you’re looking for a primer on reverse engineering an unknown hardware system. If you had fun trying out our barcode challenges perhaps deciphering EEPROM data from a simple device should be your next quest.

[Thanks James]