To generate a low-cost device, the preprocessing of the signal needs to be performed with the less quantity of components. To achieve the above, it is important to consider that the EOG has a very low amplitude ranging from 50 to 3500 μV and its bandwidth is limited from 0Hz otherwise known as the D.C. component and 30Hz according to the International Society for Clinical Electrophysiology for Vision (ISCEV) \cite{Constable_2017}. However, these signals are susceptible to very low-frequency noise commonly referred to as based line drift. Therefore, an amplification stage needs to be performed with the use of an instrumentation amplifier (AD620) and a decoupling the D.C. stage achieve by using a high pass filter with a cut-off frequency of 0.5Hz to 1Hz. Later, a low pass filter with a cut off frequency of 30 Hz is placed in cascade to the high pass filter. This low pass filter also serves as an antialiasing filter for the sampling of the signal with a microcontroller (MCU) capable of communicating with any type of computer or electronic device. To enable the communication of the MCU with any type of electronic device, a Bluetooth communication module (HC06) was used for this purpose. Finally, bipolar to unipolar conversion circuit is placed between the output signal of the low pass filter and the analog channel of the microcontroller to limit the amplitude of the signal in a range of 0V to 5V and avoid damaging the analog channel of the microcontroller. This pre-processing circuit can be appreciated in Fig \ref{149602}.