NEW TECHNOLOGIES APPLIED TO OPERANT RESEARCH: INEXPENSIVE PHOTOCELLS FOR THE ARDUINO-VISUAL BASIC INTERFACE NUEVAS TECNOLOGÍAS APLICADAS A LA INVESTIGACIÓN OPERANTE: FOTOCELDAS DE BAJO COSTO CON LA INTERFAZ ARDUINO-VISUAL BASIC Rogelio Escobar and Nadia Santillán National Autonomous University of Mexico Abstract In recent years, technological advances in electronics have been applied for de- signing fexible and inexpensive interfaces for recording and controlling events in operant research. One example, tested for accuracy and reliability, uses the popular Arduino microcontroller boards in combination with Visual Basic Express Edition programming. Tis paper describes one of the applications of the Arduino-Visual Basic interface to record movement using photocells. Each photocell uses a pho- totransistor, and an infrared LED, and allows recording the interruption of the light emited by the infrared LED. Such interruptions are detected as responses, and are used to schedule experimental events in Visual Basic programs. Tese photocells can be used in diverse experimental setings under varied conditions of illumination Rogelio Escobar and Nadia Santillán, Laboratorio de Análisis de la Conducta, Facultad de Psi- cología, Universidad Nacional Autónoma de México. Tis project was supported by grant IT300517 awarded by PAPIIT, DGAPA UNAM to the frst author. Tose interested in using the photocell described can contact the frst author for technical support (rescobar@unam.mx). Te authors thank Alexis Pérez for his assistance with previous versions of the programs. Revista Mexicana de Análisis de la Conducta • Mexican Journal of Behavior Analysis 2017 | Núm. 2 • septiembre | No. 2 • September | Vol. 43, 242 - 253 | htps://doi.org/10.5514/rmac.v43.i2.62315