MONITORING AND CONTROLLING CHEMICAL EXPERIMENTS WITH ARDUINO

Arduino is an open-source hardware and software single-board microcontroller for building digital devices and interactive objects. Arduino boards are available commercially in preassembled form or as do-it-yourself kits. The price of the board is relatively low, which is a key advantage for school use.

The current paper describes the experiences about the use of an Arduino-based device in the chemical lab for temperature and pH monitoring and remote data logging. Furthermore, the capability of the Arduino was used to implement an automatic microcontroller for the experiments temperature and pH. The assembled device was designed for monitoring and control chemical processes that require pH and temperature control, such as e.g. a chemical reaction carried out in a continuous stirred-tank reactor.

The pH is controlled by the addition of acid or base to the reaction mixture. When the device detects that the pH is beyond or below certain pre-defined threshold limits, it activates electro-valves that inject the controlling substance to the system. Temperature control was designed for both exothermic and endothermic processes, using heaters and fans as well as controlling the flow of a refrigeration jacket.

The practical exercise of assembling the microcontroller had good acceptance from the students, who had to practice multidisciplinary skills, such as programming, electronics, chemistry, chemical engineering and design of experiments. A calibration procedure was included to increase the reliability of the results, which also helped to consolidate the theoretical aspects of analytical chemistry and experiments control.