An open hardware quartz crystal microbalance
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.