AFE4490 Pulse Oximeter Breakout Board
If you don't already have one, you can buy a board from here
Measuring SpO2 aka Specific Oxygen levels in blood has never been so easy! With the new AFE4490 IC our shield does an amazing job of measuring heart rate as well as SpO2 values. Pulse Oximetry is an indirect method of measuring the oxygen levels in the blood. The sensor measures the amount of red and IR light wavelengths absorbed by blood to calculate the oxygen levels in blood. The measurement is done by a probe that clips on to a finger and contains emitters as well as a light sensor.
For more information on how exactly Pulse Oximetry works, check this out, here.
Since the amount of blood flowing through any blood vessel varies (pulses) with the rate of blood from the heart, this can also be used for measuring heart rate without the need for connecting any ECG electrodes.
Features
- TI AFE4400 Single chip pulse pulsoximetry front-end IC
- Standard Nellcor compatible DB9 connector for probe
Hardware Setup
Connect Shield to Arduino
Connect the ECG/Respiration shield to the Arduino by stacking it on top of your Arduino. This shield uses the SPI interface to communicate with the Arduino. Since this includes the ICSP header, which is used on newer Arduinos for SPI communication, this shield is also compatible newer Arduino boards such as the Arduino Yun and Due.
Connect Breakout board to Arduino
| AFE4490 pin label | Arduino Connection | Pin Function |
|---|---|---|
| GND | GND | GND |
| DRDY | D2 | Data ready(interrupt) |
| MISO | D12 | Slave out |
| SCK | D13 | SPI clock |
| MOSI | D11 | Slave in |
| CS0 | D7 | Slave select |
| START | D5 | Conversion start Pin |
| PWDN | D4 | Power Down/ Reset |
| DIAG_END | NC | Diagnostic output |
| LED_ALM | NC | Cable fault indicator |
| PD_ALM | NC | PD sensor fault indicator |
| Vcc | +5V | Supply voltage |
Software Setup
Protocentral has already written the Arduino library for AFE4490. You can obtain it by clicking the below button or by downloading it from AFE4490 Github repository.
Follow the instructions described in the Installing Arduino Library section, search for ProtoCentral AFE4490 Pulse Oximeter Breakout Board in the Library Manager and install the latest version.
Arduino Examples
PPG Streaming using Arduino Plotter
- Open serial plotter window, set the baud rate to 57600.
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Connect Spo2 probe provided along with the AFE4490 to the breakout board and place your finger inside the spo2 probe clip as described in this section and view the PPG signal in the serial plotter.
Computation of Spo2
- Open serial terminal window, set the baud rate to 115200.
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Connect Spo2 probe provided along with the AFE4490 to the breakout board and place your finger inside the spo2 probe clip as described in this section and spo2 will be displayed on the serial monitor.
PPG Streaming using Openview
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Based on the microcontroller being used, download either the Openview GUI or Openview 2.
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Connect Spo2 probe provided along with the AFE4490 to the breakout board and place your finger inside the spo2 probe clip as described in this [section].(additional-setup.md#connectiong-spo2-probe-to-finger)
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Open the GUI, make sure to select AFE4490 breakout under the Board dropdown and the appropriate Port. If everything goes well, you will be able to see the screen as pictured above.
