An ESP32 based Heart Rate Development Kit

In this article we look at a bit of a niche product featuring an ESP32 it is a Heart development kit featuring an ESP32 and a Max30102.

The kit is already comes complete and you get a typical heart rate monitor that you can put a finger in.

You can see this in the image below

The MAX30102 is an integrated pulse oximetry and heart-rate monitor module. It includes internal LEDs, photodetectors, optical elements, and low-noise electronics with ambient light rejection. The MAX30102 provides a complete system solution to ease the design-in process for mobile and wearable devices.

The MAX30102 operates on a single 1.8V power supply and a separate 3.3V power supply for the internal LEDs. Communication is through a standard I2C-compatible interface. The module can be shut down through software with zero standby current, allowing the power rails to remain powered at all times.

The MPU-6050 devices combine a 3-axis gyroscope and a 3-axis accelerometer on the same silicon die, together with an onboard Digital Motion Processor™ (DMP™), which processes complex 6-axis MotionFusion algorithms. The device can access external magnetometers or other sensors through an auxiliary master I²C bus, allowing the devices to gather a full set of sensor data without intervention from the system processor

For precision tracking of both fast and slow motions, the parts feature a user-programmable gyro full-scale range of ±250, ±500, ±1000, and ±2000 °/sec (dps), and a user-programmable accelerometer full-scale range of ±2g, ±4g, ±8g, and ±16g. Additional features include an embedded temperature sensor and an on-chip oscillator with ±1% variation over the operating temperature range

Specifications

• SoC – Espressif Systems ESP32 dual-core Tensilica SoC with WiFi 4 & Bluetooth connectivity
  
• Display – 0.96-inch IPS LCD using a ST7735 SPI controller
• Sensors
  • MAX30102 heart rate blood oxygen I2C sensor
  • MPU6050 6-axis accelerometer and gyroscope (I2C)
• Debug – Micro USB port via CP2104 USB to TTL bridge
• Misc -PCF8563 RTC, user button
• Battery – 200 mAh; charging voltage and current: 5V, 500mah via micro USB port

Development

You can develop using the Arduino IDE and/or PlatformIO. The github link at the bottom has more information

Use Arduino IDE

1. Install the correct serial port driver CP210X Driver
2. Change src/main.cpp to src.ino
3. Copy the files in the lib directory to ~/Arduino/libraries, Windows users copy to Documents/Arduino/libraries
4. Double-click to open src/src.ino
5. Change the port to the correct port and select upload

Use PlatformIO

1. Install the correct serial port driver CP210X Driver
2. Open directly to change your serial port in platformio.ini, click compile

• Note: To use TFT_eSPI, you need to select the correct model, you need to select Setup26_TTGO_T_Wristband.h, which has the same definition as T-Wristband, If the copy is in the lib folder, you can ignore it

In the examples directory contains two sample programs, FactoryTest is the factory test file, HeartRateMeter is a simple heart rate meter.

Purchase

The kit costs about £27 – buy from aliexpress

Links

https://github.com/Xinyuan-LilyGO/LilyGo-HeartRate-Kit