The use of smartphones to help life for the human being grows every day, arriving, in certain countries, to exist more apparatuses than inhabitants. But, its use to facilitate rural production is still small. The objective of the present work was to study the application of 1 Doutor, Professor efetivo do IFCE Sobral, Ceará. Email: luis.neto@ifce.edu.br. 2 Graduado em Mecatrônica industrial, IFCE Sobral, Ceará. Email: reneripardo@gmail.com. 3 Cursando eletrotécnica, IFCE Sobral, Ceará. Email: eliasfmj07@gmail.com. 4 Cursando Irrigação e Drenagem, IFCE Sobral, Ceará. Email: carolina_chags@hotmail.com.br. 5 Doutor, Professor efetivo do IFCE Sobral, Ceará. Email: tariquesc@gmail.com. 6 Mestre em em Ciências do Solo, UFC Fortaleza, Ceará. Email: amenezzes@gmail.com. L. G. Pinheiro Neto et al. Computer Vision (CV) systems, in mobiles devices, for estimating the weight of yellow melon. For this, the fruits were weighed and characterized in the plant tissue analysis laboratory of the Federal Institute of Ceará (IFCE), Sobral campus. The images were captured by portable cameras and a smartphone, being as first images acquired in an environment with artificial lighting and the rest with natural light. The algorithm for image processing used an OpenCV 3.0 CV library and the C++ programming language, being later implemented in the Java language. For training the algorithm used 50 melons, and 20melons for the test. The tests indicated that the algorithm was able to segment the melon and estimate the weight with an average error of 11%. With the application developed, melon growers can estimate theirs weight without having to harvest it, making farmer decision-making easier.