- Published: Monday, 06 June 2011
- Written by Jon Chandler
- Hits: 3909
On Sunday, my partner Eric and I had a table at the first-ever Kitsap County, Washington Mini Maker Faire, (Maker Faires are sponsored in part by Make Magazine). It was a gloriously nice day for the Seattle area and one of the few nice ones we'd have this year. Over 400 people attended which was a nice scale and allowed lots of time for interaction.
We decided that we wanted to present sort of a broad view of "making" - that the technology to go from design to hardware to real-world applications was within everyone's reach. Eric planned to combine "techie" and "foodie" and demonstrate sous-vide cooking as something that "maker" technology makes possible.
I've mentioned sous-vide here before, but allow me to describe it again. Sous-vide cooking is low-temperature, long-time cooking with food sealed in a plastic bag in a water bath. Food is cooked for many hours (4 hours or longer) at the desired serving temperature. This results in things like awesomely tender beef that's never dried out, cooked exactly to the level desired. For example, if you want rare beef, any size piece of meat will be exactly at the level from edge to edge! Take it out of the bag, brown it briefly on each side and dinner is ready with about 3 minutes of effort from the time you pull the meat out of the bath. An unbelievable detail is that the meat reaches exactly the doneness level you want and goes no further - if dinner is delayed an hour or two, no problem. If dinner is delayed 24 hours, still no problem! The food is ready when you want it.
Sous-vide is a developing technology. Until recently, a water-bath system to to this cost many thousands of dollars. Recently, Williams Sonoma introduced a system for $1200. Our system was somewhat cheaper. We purchased an electric turkey fryer at Lowes on closeout shortly after Christmas for $25. To control the temperature (extremely precision temperature control is key) we use a Chinese PID controller, a thermocouple and an SSR (solid state relay) to control the turkey fryer. Our total cost was under $100.
The Maker Faire was graciously hosted by the Seventh Day Adventist School in Poulsbo, Washington. Eric wanted to demonstrate the sous-vide technology by handing out samples. If you're like me, you may not be aware that the Seventh Day Adventist faith advocates a vegetarian diet. Handing out beef samples, no matter had tender and delicious, would not have gone over well. Instead, Eric planned to serve low-temperature cooked eggs, which would be an acceptable part of their diet and considered a delicacy former limited to French chefs, requiring weighing an egg and timing the cooking to the second. Using the sous vide cooker, eggs go in before bed and are ready whenever you wake up in the morning.
Saturday night, I was frantically trying to figure out what to show to provide a little "gee whiz" while Eric put 6 dozen eggs in the turkey fryer to cook. Early Sunday morning I was packing up stuff to take and heard Eric shout "Oh $%^%&^" shortly after he made his way to the kitchen. As Murphy would have it, with 6 dozen eggs cooking, the PID controller had picked the worst possible time to fail, and with Murphy working overtime, when it failed, it supplied full power all night long! Instead of 6 dozen perfect eggs, we had 6 dozen very hard boiled eggs.
Scratch the samples. Eric talked to many people doing the fair, extolling the virtues of sous vide. He made some believers - one couple he talked to at length returned an hour later. "We just purchased a turkey fryer." He was knowledgeable in microcontrollers and electronics, so I handed him one of the new TAP-20-USB boards and one of the thermocouple expansion cards (which arrived on Saturday) and told him to stay in touch. Since our PID controller failed, obviously I'll have to get the PIC-controller running on the new card stack quickly!
For my part, I showed many of the things you've seen here. The servo clock, TAP-28 boards of course, the new TAP-20-USB boards with several displays. One of the boards was controlling a Sure Electronics LED bargraph display with LEDs going back of forth. The test display said "Gratuitous blinky LEDs. It's cool. Admit it." One of the new boards was coupled to the thermocouple expansion module - the code developed on the breadboard worked perfectly.
One of the things that got the most attention was something I've not discussed at Digital-DIY before, the "meal-minder" clock. We developed this rather simple aid when by dad was in assisted living, suffering from cognitive impairment. He had a habit of falling asleep it the lights blazing, and then waking up and being confused if it was day or night. The clock might read 12 o'clock so he go to the dining room expecting lunch when it was actually midnight.
The meal-minder is an extremely simple concept. In a Ikea wall clock the standard quartz movement was replaced with a 24 hour movement, and only the hour hand was fitted. The hour hand makes one revolution a day. Six AM is straight up, 6 PM is straight down and noon is 90 degrees to the right. But the clock isn't marked like a clock - it's marked by the day-part. Breakfast, lunch, dinner and bedtime. If dad woke up and wasn't sure if it was day or night, a look at the meal-minder told him to go back to bed or get ready for lunch. A simple devide that kept day more independant for a couple years.
We talked to many like-minded people and found that some people in the area share some interests. The fair was a lot of fun, but if any of you have done trade shows, you know how hard it is to be "on" for 6 hours straight.
The picture below is our space at the fair. The turker fryer is the right and the screen is showing the levels of doneness for beef.
Here's a closer view of the sous-vide section.
This view is a closer view of "my" side. Across the top from the left is the meal clock, the irradiance meter, the 10 Buck power supply, the servo clock, in the plastic case is a TAP-20-USB and thermocouple module, on the cardboard box at TAP-20-USB boards with displays, the signal generator, the demo board for my pcb course and finally, the laser-cut acrylic case.
The USB-20-USB boards are designed for use with a display and to mount in an enclosure. Connectors stick out the back and bottom sides, making it kind of diffiucult to use on the bench or out side of enclosure. In the short time to get things together for the fair, I didn't have time to come up with any kind of mounting system. While I swas setting up the table at the fair, the idea hit me. I made a slot in the cardbox box under the display, unplugged the display and reconnected it with the pins going through the slot to the TAP-20-USB inside the box.
This photo shows the back side of the original geeky clock with the hand-wired perf board that helped to inspire the TAP-28 which is next to it. Also, you can see my use of multiple 5 volt former-cell phone-supplies to power everything.
Finally, here's a closeup picture of the backdrop to our table, showing the Make ideal.
The Kitsap Mini-Maker Faire was a lot of fun and we had a chance to talk to a lot of interesting people. I'd definitely recommend checking one if there's one nearby. At the end of this month, there's a full size Maker Faire in Vancouver, British Columbia, Canada. If schedules permit, we'll go to that one as attendees, so we can see what everybody else is doing.
A special thanks goes out to TJ McCue and all the many volunteers who worked hard to pull this great event together in a short time. Good show as my former boss use to say, which was high praise from him and meant more then many sentences would have.