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AN05: Thermal PI control

PI control is a simple and powerful control algorithm.  See the video below, that uses LArVa source code modified to include PI control code.




To learn more, download LArVa or view a video on Building a P controller.

AN04: Temperature Data Logging Using LArVa


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This application note describes a production problem and a lab automation solution using Arduino, LArVa and an RTD as a thermal logging solution that costs under $35. 

The Mystery of the dendric growth

An Angstrom Designs consulting client experienced a surge in returns of a custom, micro-machined nanostructural component they sold to their customers.  Further inspection showed unexpected dendritic growth of a metal portion of the nanostructures during storage.  The shelf-life of the nanostructures was radically reduced from just a few months prior and the growth was threatening to halt the company’s ability to distribute this critical component.

As happens far too often, many things had changed over the previous several months.  The possible culprits included a change to the cases used for storage, multiple iterations of the manufacturing process and storage of the devices in a different part of the warehouse than before.

Solving the Problem:  Look at Everything

Desperate to track down the problem the company decided to try as many approaches as possible.  Because the growth took several weeks to detect, the root cause would have to be determined in as few iterations as possible.

Most of the effort was focused on changes in the final few steps of the nanofabrication and cleaning process.  In addition, several of the old-style storage cases were produced so side by side storage tests to could be undertaken to see if the new cases were causing the problem.  Finally, knowing the growth occurs faster at high temperatures, the investigation team decided to add storage temperature to its test matrix.

Temperature Test Set-up

The investigation team decided to do side-by-side testing of the new and old-style storage cases in three different locations: the old storage location, the new storage location and inside a refrigerator.

Because the locations were not close to one another, the team needed three temperature logging stations.  Wanting to save money and move quickly, the team decided to use LArVa running on an Arduino with an RTD for sensing temperature.  The total cost was less than $100 for all three stations combined and the parts were procured in under a week. 

Using the LArVa simple graph application the team monitored all 3 locations at 20 data samples per minute continuously.

AN02: Measuring Temperature For Under $35 In Hardware Using LArVa


AN02 has been renamed UG04, now located in User Guides.

AN01: Basic Voltage Acquisition Using LArVa


AN01 has been renamed UG03, now located in User Guides.