LED technology (Light Emitting Diode) has achieved increasing prominence in the development of new sensing systems, lighting and communications. The reduction in manufacturing costs has made it possible to increase their use and the search for new applications. However, the technical information is difficult to associate with devices that are available in the market and equipment necessary to characterize them can significantly increase the cost of a project. This scholarship was obtained current vs. voltage curve (characteristic curve) in 5 high-brightness LED using a system of signal generation and acquisition purpose built with a low cost microcontroller. Additionally using a low cost spectrometer was obtained wavelength. With the data obtained and the Planck model, we found the fitting parameters needed to estimate the emission wavelength of an LED according to the point of intersection with the voltage axis of the linear region of the LED. Finally, the model has found it possible to use the wavelength with a relative error less than (3.16)% counting only with voltage and current data that can be obtained easily.