Design and implementation of an autonomous system for double Langmüir probe applications C. Jaramillo*, J. M. Jaramillo, J. E. Correa  Universidad EAFIT *Corresponding author: cjaram54@eafit.edu.co ABSTRACT This work describes a low cost voltage source, designed and built to offer specific characteristics which satisfy the requirements of a Langmüir double probe application. The source can invert the output polarity using a relay and can do a voltage sweep using a mechanical system based on a linear potentiometer coupled with a stepper motor. The system has a microcontroller Arduino Uno and a μLCD touch display as user interface. The power source presents an output, which can vary between 0 and 46 V approximately with steps of 0,006 V. The microcontroller registers pairs of voltage and current sequentially, with a time interval determined by its clock (16MHz). In order to minimize errors, the system estimates a statistical mean, using a number of pairs of data defined by the user. The data is provided via USB and/or in a detachable μSD in a .txt file. Resumen Equipo de caracterización de plasmas fríos compuesto por Sonda de Langmüir compuesta por Procesamiento de datos Fuente de voltaje Sistema de control de potencial Sistema de adquisición de datos Software para Obtener curvas I-V sirve para Obtener parámetros del plasma Regulador Sistema de potencia Motor Potenciómetro Polarizar sonda Realizar barrido de potencial Variar salida de la fuente Amplificadores operacionales Memoria extraíble Relé Invertir polaridad Sistema de protección Pormedio de HMI uLCD Enviar datos a HMI Controlar de sistema de barrido de potencial Microcontrolador Por medio de Pantalla táctil Leer I-V Puerto analógico Resistencia CONCEPT MAP RESULTS SCHEMATIC DIAGRAMS V(I) = 1,0345V - 0,0248 R² = 0,9999 CONCLUSIONS An adjustable voltage DC source with invertible polarity output was implemented. It allows to vary the output from 0 V to 44 V. Everything is controlled by an Arduino Uno microcontroller. It also has an interface using a touch display. The output presents a linear variaton, with 670 steps of 0,007 V aproximately. Prof. M.Sc. Carlos Correa for discussion and ideas about the development. Physics Laboratory for technical support. ACKNOWLEDGMENTS