Unlock the secrets of brainwaves with our cutting-edge EEG technology
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Hardware Overview
How does it work?
EEG Click is based on the INA114, a precision instrumentation amplifier (IA) by Burr Brown®, a division of Texas Instruments specialized in high-performance analog and mixed-signal ICs. This IC offers low noise, LASER-trimmed offset voltage, and a good common-mode rejection ratio. It uses a single resistor to set up its gain, which can easily be set up to 10,000. On this Click board™, the INA114 IA has its gain set to about 12 times. Further, amplification and signal filtering is done by the MCP609, a four-channel op-amp from Microchip, so that the final gain factor is about 7800 times. Such high amplification is necessary to amplify faint voltages generated during brain activity. To fine-tune the amplification, a multi-turn precision potentiometer allows for setting the gain of the intermediate amplification stage between
10 and 100 times. Since the "brain waves " can be both positive and negative, EEG click uses a virtual GND at the potential of 2.048V. This also helps to reduce the noise from the common GND, improving the quality of the readings. The amplified brain activity signal is available at the AN pin of the mikroBUS™, allowing sampling by the host MCU. EEG measurements should be ideally conducted in an electrically isolated room since any electromagnetic interference (EMI) could corrupt the measurement data. However, the INA114 offers some EMI protection, as it features an outstanding common-mode rejection ratio (CMRR), allowing it to cancel out most of the induced interferences successfully. This Click board™ uses a 3-electrode setup, which can be connected over a 3.5mm Jack connector on the
Click board™. Although the best results can be achieved using silver-chlorine-plated electrodes, any electrode can be used. EEG uses the DRL electrode placement scheme: two electrodes are placed behind the ears, while the third is placed on the forehead. The DRL electrode (on the forehead) helps eliminate the common voltage, while two other electrodes are connected to the differential inputs of the INA114 IA. The complete signal path is very well protected against voltage spikes and transients that might appear as a result of the electrostatic discharge (ESD) in contact with the human body, so there is a set of ESD suppressing diodes and TVS diodes, which prevent sensitive IA and operational amplifiers on its output to become damaged by ESD events.
Features overview
Development board
Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an
ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the
first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
32
Silicon Vendor
Microchip
Pin count
32
RAM (Bytes)
2048
You complete me!
Accessories
Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
3-wire ECG/EMG cable comes with a convenient 3.5mm phone jack, and it is designed for electrocardiogram recording. This 1m cable is a practical companion for medical professionals and enthusiasts. To complement this cable, you can also use single-use adhesive ECG/EMG electrodes measuring 48x34mm, each equipped with an ECG/EMG cable stud adapter. These electrodes ensure a seamless experience when paired with our ECG/EMG cable and guarantee reliable ECG/EMG signal transmission for comprehensive cardiac monitoring. Trust in the accuracy and convenience of this setup to effortlessly record electrocardiograms and electromyograms with confidence.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Track your results in real time
Application Output via Debug Mode
1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.
2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.
Software Support
Library Description
This library contains API for EEG Click driver.
Key functions:
eeg_read_an_pin_value
- This function reads results of AD conversion of the AN pineeg_read_an_pin_voltage
- This function reads results of AD conversion of the AN pin and converts them to proportional voltage level
Open Source
Code example
This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.
/*!
* @file main.c
* @brief EEG Click Example.
*
* # Description
* This example demonstrates the use of EEG Click board.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes Click board.
*
* ## Application Task
* Reads ADC value and sends results on serial plotter every 5 ms.
*
* @author Jelena Milosavljevic
*
*/
#include "board.h"
#include "log.h"
#include "eeg.h"
static eeg_t eeg; /**< EEG Click driver object. */
static log_t logger; /**< Logger object. */
uint32_t time = 0;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
eeg_cfg_t eeg_cfg; /**< Click config object. */
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, " Application Init " );
log_printf( &logger, " ----------------------------------------------\r\n" );
log_printf( &logger, " ***EEG click*** \r\n" );
log_printf( &logger, "----------------------------------------------\r\n" );
Delay_ms( 2000 );
// Click initialization.
eeg_cfg_setup( &eeg_cfg );
EEG_MAP_MIKROBUS( eeg_cfg, MIKROBUS_1 );
if ( ADC_ERROR == eeg_init( &eeg, &eeg_cfg ) ){
log_error( &logger, " Application Init Error. " );
log_info( &logger, " Please, run program again... " );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
uint16_t eeg_an_value = 0;
if ( eeg_read_an_pin_value( &eeg, &eeg_an_value ) != ADC_ERROR ) {
log_printf( &logger, " %u,%lu\r\n", eeg_an_value, time );
Delay_ms( 5 );
time += 5;
}
}
void main ( void )
{
application_init( );
for ( ; ; ) {
application_task( );
}
}
// ------------------------------------------------------------------------ END