Most of us are content to get our semiconductors from the usual sources, happily abstracting away the complexity locked within those little epoxy blobs. But eventually, you might get the itch to roll your own semiconductors, in which case you’ll need to start gearing up. And one of the first tools you’ll need is likely to be something like this DIY tube furnace.

For the uninitiated, [ProjectsInFlight] helpfully explains in the video below just what a tube furnace is and why you’d need one to start working with semiconductors. Perhaps unsurprisingly, a tube furnace is just a tube that gets really, really hot — like 1,200° C. In addition to the extreme heat, commercial furnaces are often set up to seal off the ends of the tube to create specific conditions within, such as an inert gas atmosphere or even a vacuum. The combination of heat and atmospheric control allows the budding fabricator to transform silicon wafers using chemical and physical processes.

[ProjectsInFlight]’s tube furnace started with a length of heat-resistant quartz glass tubing and a small tub of sodium silicate refractory cement, from the plumbing section of any home store. The tube was given a thin coat of cement and dried in a low oven before wrapping it with nichrome wire. The wrapped tube got another, thicker layer of silicate cement and an insulating wrap of alumina ceramic wool before applying power to cure everything at 1,000° C. The cured tube then went into a custom-built sheet steel enclosure with plenty of extra insulation, along with an Arduino and a solid-state relay to control the furnace. The video below concludes with testing the furnace by growing a silicon dioxide coating on a scrap of silicon wafer. This was helped along by the injection of a few whisps of water vapor while ramping the furnace temperature up, and the results are easily visible.

[ProjectsInFlight] still needs to add seals to the tube to control the atmosphere in there, an upgrade we’ll be on the lookout for. It’s already a great start, although it might take a while to catch up to our friend [Sam Zeloof].

You have to be pretty ambitious to modify a clock to run for 50 years on a single battery. You also should probably be pretty young if you think you’re going to verify your power estimates, at least in person. According to [Josh EJ], this modified quartz analog clock, which ticks off the date rather than the time, is one of those “The March of Time” projects that’s intended to terrify incentivize you by showing how much of the year is left.

Making a regular clock movement slow down so that what normally takes an hour takes a month without making any mechanical changes requires some clever hacks. [Josh] decided to use an Arduino to send digital pulses to the quartz movement to advance the minute hand, rather than let it run free. Two pulses a day would be perfect for making a 30-day month fit into a 60-minute hour, but that only works for four months out of the year. [Josh]’s solution was to mark the first 28 even-numbered minutes, cram 29, 30, and 31 into the last four minutes of the hour, and sort the details out in code.

As for the low-power mods, there’s some cool wizardry involved with that, like flashing the Arduino Pro Mini with a new bootloader that reduces the clock speed to 1 MHz. This allows the microcontroller and RTC module to run from the clock movement’s 1.5 V AA battery. [Josh] estimates a current draw of about 6 μA per day, which works out to about 50 years from a single cell. That’s to be taken with a huge grain of salt, of course, but we expect the battery will last a long, long time.

[Josh] built this clock as part of the Low-Power Challenge contest, which wrapped up this week. We’re looking forward to the results of the contest — good luck to all the entrants!

Marco Mauro is a physicist currently employed as Scientific Coordinator at Novaetech, the first Spin-off Company of the National Institute for Astrophysics (INAF) in Italy. He shared with us all the info about a project he’s been working on  and based on Arduino Micro.

OpenQCM is a fully open source scientific microbalance capable of weighing mass deposition down to 1 billionth of gram:

The sensing core of the microbalance is a piezoelectric quartz crystal oscillator. The deposition of a very tiny mass on the surface causes the variation in the quartz frequency. openQCM belongs to a new generation of innovative smart sensor which boast high resolution and ultra high mass sensitivity. The open source strategy made the creation of openQCM available at low cost which represents a bit fraction of the cost of similar scientific products.

openQCM was built keeping in mind the emergent principles of the open source hardware movement. The open source hardware gives people the freedom to control their technology through the open exchange of all the project features, 3D design, electronics and software. The open hardware potentiality is even greater when it comes to hardware for scientific applications.

openQCM is exactly something like that, the first open hardware quartz crystal microbalance with applications in a wide range of scientific fields, such as chemical and biological sensing, material science.

openQCM has an Arduino Micro board inside at heart. By hacking the timer counter of the AtMega32U4 Arduino microcontroller, it is possible to measure the quartz crystal frequency variations using the 16 Mhz microprocessor clock. openQCM team has designed an Arduino Micro shield with an embedded quartz crystal oscillator driver circuit and a temperature sensor. The output of the quartz crystal oscillator driver is fed to the Arduino Micro timer counter and the analog value of the temperature sensor is fed to the analog pin of the board. This configuration allow you measure the quartz crystal frequency with a resolution of 1 Hz, which roughly corresponds to a mass resolution of 700 pg over the entire quartz surface in air.

One of the major challenge of an open hardware project is that such devices require funding to prototype and manufacture. That’s why the openQCM team have selected the 3d printing technology to keep high quality and low cost. Using 3d printing to print out the prototypes via the SLS process from OS Formiga P100, P110, P395, and P730, the openQCM team created the device’s parts, which required a precision down to 60 µm.

The open source concept made openQCM publicly available so that anyone (scientists, technology enthusiast, makers, hobbyist …) can study, modify, and develop the hardware based on the original design. openQCM is now working and ready to win the heart of the scientific community and more.

Go and make one yourself!