Automatic Espresso Loader For Those Late Night Hack Sessions

June 7, 2011 by Jeremy Cook 10 Comments

For [Roy’s] graduate electronics class, he decided to make something that many in and out of the hacking world would certainly love, an automatic espresso loader. One can choose from three flavors available. In order to accomplish this, a Parralax Propeller board is used to control three servos that regulate the amount of coffee dispensed, chosen by a handy LCD HMI (human machine interface).

After the coffee is dispensed, the chute swings out of the way. A modified inkjet cartridge carrier (from a dead printer) is then used to compact the beans. Check out the video of this machine in action after the break. Continue reading “Automatic Espresso Loader For Those Late Night Hack Sessions” →

PID Sous-Vide Slow Cooker – Bon Appétit!

April 5, 2011 by Jason Komp 22 Comments

In search of a perfectly-cooked brisket, [Aaron] recently completed this DIY PID-controlled sous-vide slow cooker. Sous-vide (French for “under vacuum”) is a cooking technique in which foods are typically vacuum-sealed and then cooked in a relatively low temperature water bath for an extended period of time. This is done to minimize temperature gradients throughout the food to ensure even cooking. Precise regulation of the water temperature is the key to ensuring that the results are exactly as desired – when cooking for many hours or days, even a few degrees discrepancy can greatly influence the final product.

A few months ago we featured a similar hack that utilized a simple switching temperature controller spliced into an extension cord. Although probably sufficient for most aspiring “hacker-chefs”, the temperature was not as stable as it could be. The problem is that it takes time for the heat generated in the slow cooker’s heating element to reach the temperature probe (and food) suspended in the water bath. By the time the probe reads the elevated temperature, the element is already too hot and the temperature overshoots the target. One way to mitigate this effect is to circulate the water to minimize temperature gradients, as is done in many of the expensive commercial units. In order to achieve similar results, [Aaron] instead created a PID controller that uses temperature feedback over time to precisely maintain the desired temperature and reduce any deviations resulting from outside disturbances.

The build is covered in detail and looks great in a custom acrylic enclosure. All of the board schematics, enclosure layout files, and source code are available under Creative Commons licensing at the bottom of his blog page. A good deal of time is also spent addressing the actual PID programming and tuning – something that could be useful for many different hacks requiring precise feedback control.

The end result is a professional looking control box and a slow cooker that is able to maintain temperature within 1°F even while using a DS1820 temperature sensor that is only rated as accurate to 0.5°C (0.9°F). From the pictures it looks like [Aaron] has finally achieved brisket bliss! Now the only question remaining is: what is the best setting for reheating left-over pizza?

PID Controlled Bradley Smoker Clone

February 11, 2011 by Mike Nathan 21 Comments

Bradley smokers are coveted for their ease of use, as they require very little interaction from the user once the hopper is loaded with wood pucks and the machine is powered on. The more robust models are quite pricey, so [Maukka] decided to build his own version of a Bradley smoker as an add on to his existing unit. He fabricated a smoke generator out of aluminum, including all of the components you would normally find in an automated smoker. Once the hopper is loaded with wood pucks, the smoker runs autonomously, shuffling new pucks onto the heating element, presumably at timed intervals. The main barrel of the smoker has a separate PIC-controlled heating element installed, and is connected to the smoke generator by an aluminum duct. This configuration allows [Maukka] to cold smoke items such as fish, nuts, and cheeses using the smoke generator by itself, while also permitting the smoking of meats at far higher temperatures when the main heating element is used. This is truly a fantastic build, and the cold smoker component is something I would love to have as an addition to my Weber bullet.

Be sure to explore his blog a bit to catch all of the build details, as they are separated into various posts.

[Thanks Hali Batsuiba]

Refurbishing A Refrigerator For Fermenting

January 25, 2011 by Caleb Kraft 12 Comments

[Mikey Sklar] wrote in to show us how he refurbished a neighbors useless refrigerator as a fermentation chamber. [Mikey] is a fan of making breads, kemchi, yogurt, and tempeh. To make these, it helps to have a completely controlled temperature for them to ferment in. [Mikey] developed a temp controller for this in the past, but had to either build a control box or use a giant chest freezer. This is not optimal for limited space, such as a kitchen. He got lucky when a neighbor tossed a wine cooler into the trash. These little coolers are perfectly sized for a kitchen and even have a glass front so you can keep an eye on what is going on inside without having to open it and effect your temps. [Mikey] ripped it open, replaced the peltier cooler with a large heat lamp and his temp controller. Since he was making yogurt with this one, he needed only to heat it. The final product turned out pretty effective.