Adding an additional fan to your PC is usually pretty straightforward, but as [Randy Elwin] found, this isn’t always the case with the newer Small Form Factor (SFF) machines. Not only was the standard 80 mm fan too large to fit inside of the case, but there wasn’t even a spot to plug it in. So he had to come up with his own way to power it up and control its speed.
Now if he only needed power, that wouldn’t have been a problem. You could certainly tap into one of the wires coming from the PSU and get 12 V to spin the fan. But that would mean it was running at max speed the whole time; fine in a pinch, but not exactly ideal for a daily driver.
To get speed control, [Randy] put together a little circuit using an ATtiny85, an IR LED, and a LTR-306 phototransistor. The optical components are used to detect the GPU fan’s current speed, which itself is controlled based on system temperature. Using the GPU fan RPM as an input, a lookup table on the microcontroller sets an appropriate speed for the 80 mm case fan.
One could argue that it would have been easier to connect a temperature sensor to the ATtiny85, but by synchronizing the case fan to the computer-controlled GPU fan, [Randy] is able to manually control them both from software if necessary. Rather than waiting on the case temperature to rise, he can peg the GPU fan and have the external fan speed up to match when the system is under heavy load.
If you’re looking to do something awesome with a graphing calculator, [Chris] is the guy to go to. He’s literally written the book on the subject. His PartyMode project, however, has absolutely nothing to do with calculators. It’s a fantastic display of lights, colors, and sounds that has been rebuilt again and again over the years, and something [Chris] has finally gotten around to documenting.
The idea for [Chris]’ PartyMode is a single button that will transform a room from a boring computer lab or dorm room into a disco with 22.4 channel sound, and computer displays used as panels of color. The first version began in the lab in his school’s EE department that included ten CRT monitors. There were a few VUFans featured on the good ‘ol Hackaday, but a few problems with regulations and politics brought this version of PartyMode to a premature end.
The second version is a miniaturized, ‘press a button, get a party’ setup with a crazy number of RGB LEDs, a few more of those computer fan VU meters, and a Bluetooth app to control everything. Unlike the first version, the PartyMode 2.0 is fully independent from a computer, instead relying on an ATMega to do the audio processing and handling the Bluetooth interface. Judging from the videos below, it’s quite the site, and if you need an instant party, you could do much worse.
Maybe you saw the previous post and thought, “Well, that’s all well and good, but why is such a stylish case being used to ventilate cat feces?” Antec has heard your cries and has created a computer case with all the lovely curves of a litter box and just as much airflow. The Skeleton case has an open frame design with a 250mm fan on top. You mount the motherboard to a sliding tray. The power supply and hard drives are mounted underneath. It’s an interesting idea and easily replicated, but if cooling had been the goal, it would be a lot more enclosed. You can see the case with components installed on TweakTown.