We’ve all been there. The day is done and it’s time for a cold one but you neglected to put more beer in the fridge after imbibing the last bottle the night before. You could chuck it in the freezer and revisit your attempt at refreshment in an hour. But if you need a malty beverage right now there’s no faster route than a beer chiller.

This particular beer chilling device is [Michael's] entry in DEFCON 19′s Beer Chilling Contraption Contest. It can take a pint of beer from 90 degrees down to 45 degrees in just four seconds. Of course there’s a fair amount of setup time before you’re ready to use it. The device is a pipe within a pipe. The inner pipe houses the beer and the pipe surrounding it provides a containment area for a chilling liquid. [Michael] chose to use liquid carbon dioxide as a coolant because of it’s boiling temperature when under pressure. That is to say, the hottest part of the CO2 liquid is around the walls of the center pipe. By carefully dialing in the pressure of that outer chamber, the CO2 will boil away into gas as it cools the beer, making room for more liquid CO2 to contact the pipe and continue the cooling process.

The Pinewood Derby is a classic Cub Scout competition where dads and sons come together to build a small-scale race car. You start with a kit that includes a block of wood for the body, as well as four plastic wheels and four nails to act as axles. Most innovations in the ‘sport’ center around reducing friction between the wheels and the axles, and making the body as aerodynamic as possible.

This year [Sliptronic] grabbed an extra kit and threw the rules out the window by powering the car with compressed carbon dioxide. He used a 3D printer to make a housing for two CO2 cartridges that mounts on the center of the chassis. An official Pinewood Derby race track is on an incline and has a wooden gate that keeps each car in place until it is dropped to start the race. [Sliptronic] is using this gate as the triggering mechanism. Springs on either side of the car pull against an arm at the back of the vehicle. This arm is held in place by a rod protruding out the front of the vehicle. When the start gate is dropped that rod releases the trigger, which is pulled up by the springs to pierce the CO2 cartridges. You can see an overview of how that mechanism works in the video after the break.

[Rich] over at Evil Mad Scientist Labs took it upon himself to make eating fruit a little more enjoyable for his kids by infusing it with CO2 using his CO2inator. Observing the same principles used in making soft drinks and force-carbed beer, he decided to build a CO2 pressure chamber for use in his kitchen. He gathered a handful of easy to find components to construct his rig, including a household water filter housing and a CO2 cylinder from a paintball gun. He has some helpful hints for those who are not familiar with the process, noting that refrigerated fruit absorbs the gas more quickly than warm, and that considering the water content of the fruit is important when selecting what to carbonate.

Once [Rich] had everything safely connected and checked for leaks, in went the fruit. After about half an hour to an hour, the fruit was carbonated, much to the delight of his children. This looks like a quick and fun project for adults and kids alike, that can easily fit into a busy weekend schedule.

[via Neatorama]

[Bill Fienup] and [Barry Kudrowitz]‘s robots, The Automatos, have been leaving a sticky path of destruction all over the internet. Their sole purpose: to crap ketchup. They accomplish this feat by dumping a CO2 cartridge into a ketchup bottle at the push of a button, leading to some pretty awesome results.  While the details are a little sparse it appears that they are using RC cars for the base and a small air gun CO2 cartridge to push the ketchup. The latest version aka the Atuomato 4 appears to be multi-actuated and can shoot more than once for maximum ketchup proliferation. See some videos of it in action after the break.

As part of his Master’s dissertation [Salvador Faria] built a sensor suite for wine monitoring. He needed to develop a method of tracking data inside the wine cask during the vinification process. What he came up with eclipses the wine cellar temperature monitors we’ve seen before.

He picked up pH, temperature, carbon dioxide, alcohol, and relative humidity sensors from familiar vendors like Seeed, Parallax, and SparkFun. His original idea was to develop a floating probe that housed the entire package but he had quite a bit of trouble getting everything inside and maintaining buoyancy. The solution was a two-part probe; the stationary portion seen mounted on top of the cask houses the microcontroller, RF 433 MHz transmitter, and the gas sensors. Tethered to that is a floating probe that measures pH and temperature. Data is sent over radio frequency to an HTTP POST server every minute.

[Alexander] sent in his entry into a “creativity contest” at his university. He and some friends put together this dry ice cannon.  Take note of the creative mechanism they used to mix the water with the dry ice. A large amount of gas is expelled as soon as the two begin to meet. If the gas is supposed to escape through the same opening, it is difficult to get all the material through. They have added a second opening just for the exhaust during mixing. Great job guys. How about some downloadable plans.

The registration desk hasn’t opened yet at ShmooCon 2009, but we’re already running into old friends. We found [Larry Pesce] and [Paul Asadoorian] from the PaulDotCom Security Weekly podcast showing off their latest ShmooBall gun. ShmooBalls have been a staple of ShmooCon from the very beginning. They’re soft foam balls distributed to each of the attendees who can then use them to pelt the speakers when they disagree. It’s a semi-anonymous way of expressing your dismay physically. [Larry] has been building bigger and better ways to shoot the ShmooBalls for the last couple years. You may remember seeing the 2008 model. This year the goal was to make the gun part much lighter. The CO2 supply is mounted remotely with a solenoid valve and coiled air line. The pistol grip has a light up arming switch and trigger. The gun is fairly easy to transport: the air line has a quick disconnect and the power is connected using ethernet jacks.

For those who use these little cartridges, you know how quickly the price can add up.  [steve] takes us through the process of adding a valve to a spent cartridge so it can be refilled. Over all, it doesn’t seem too difficult, and [steve] offers lots of tips to increase longevity and reliability. It isn’t very often that we show a hack here that doesn’t involve some kind of electronics, so take a break from the resistors and microprocessors for a moment and enjoy.

[thanks Wolf]

The 25th is the deadline for the Design Challenge. Don’t freak out, just get it submitted before I get up on the 26th, and I’ll call it good.