This article presents the design and construction of a wireless electrocardiograph of one derivation using active electrodes, the stages of adequacy of the signal originated from the electrodes, the digitization stage, digital filtering, transmission using Bluetooth towards an Android mobile device, where there is located an apk which was developed using the IDE Processing, are described. The tests determine that noise and harmonic distortion do not affect in a significant way the system, also prove a right functionality from the system through comparisons made using signal to noise ratio (SNR), total harmonic distortion (THD) and signal to noise ratio and distortion (SINAD) from multiple electrocardiography signals which were acquire by the prototype and a Cassy Sensor ECG device used as a reference.