MicroECG

Overview

MicroECG is an ECG monitoring module based on nRF51822 BLE chip and BL1860 ECG chip, which can transport heart information through either UART or BLE. Users can control nRF51822 via AT Commands. Also, they can use the open-source software to develop their own firmware, making it to support more functions.

The heart information includes row data and the heart rate. The row data is the result of ADC detection, representing the strength of heart beat. The row data can be used to draw ECG directly. And the heart rate is the result of calculation with the row data.

This ECG module is easy to use. Data can be transported through either UART or BLE. When the switch on the board is set to the BLE side, data can be transported through BLE. In this case, one can use app on one’s phone to receive the heart rate from this module. When the switch on the board is set to the UART side, data can be transported through UART. In this case, one can control the board with some AT commands.

Go shopping MicroECG (SKU:IM161018001)

Specification

PCB Size	22mm X 26mm X 1.6mm
Input Voltage (vcc)	3.3V
Microprocessor	nRF51822
Interface	UART, BLE

Electrical Characteristics

Parameter	Min	Typical	Max	Unit
Input Volt	3	3.3	3.6	VDC
Input voltage VinH	3	3.3	3.6	V
Input voltage VinL	-0.3	0	0.5	V
Baud rate		9600		bps

Hardware

J7
No.	Pin Name
1	3V3
2	SWDCLK
3	SWDIO/RST
4	TXD(P0.12)
5	RXD(P0.11)
6	GND
7	GND
8	LA
9	RA
10	RLD
11	NC
12	NC

Interface Functions

• J7 GPIO port: serial output port, this port also connects to CP2102 USB-to-TTL chip, users can send and receive data through USB.
• J5, J6 GPIO ports: general GPIO port, users can self-define the functions.
• Output Data Configuration Switch: users can select whether to use BLE to transport heart rate data. The serial port always can be used no matter which side you switch to.
• USB: users can send and receive data through USB, and power the battery through USB.
• Battery Socket: 3.7V lithium battery connector.
• Pole Socket：ECG cable interface, detect heart rate by using ECG electrodes to contact human right and left hand skin. Note: LA electrode(black buckle) is attached to left hand, RA electrode(white buckle) is attached to right hand, RLD electrode(red buckle) is attached to right hand.

Usage

• BLE case

1.Set the switch on the board to the BLE side.

2.Power on the board with either USB cable or battery.

3.Put the 3 detectors (red、black、white) on the arms and connect the cable to the board.

4.Run the BLE app on the phone. Click and turn into the “HRM” mode and then connect to the “ITEAD_BL18_ECG” device.

5.Just wait a while and the heart rate will be displayed.

• UART case

1. Set the switch on the board to the BLE side.

2. Power on the board with either USB cable or battery.

3. Put the 3 detectors (red、black、white) on the arms and connect the cable to the board.

4.Connect the Uart interface to another mcu or connect the USB cable to PC.

5. Control the board with following AT commands:

1.“AT\r”

This command is a string and used to test the UART connection.

When the UART is working , “OK\r\n” will be returned.

2.“ATdataTypeR\r”

This command is a string and used to set the data type to row data.

When the command runs successfully , "Type:R\nOK\r\n" will be returned.

This command can not run successfully when the “ATstartRead\r” is running.

3.“ATdataTypeH\r”

This command is a string and used to set the data type to heart rate.

When this command runs successfully, "Type:H\nOK\r\n" will be returned.

This command can not run successfully when the “ATstartRead\r” is running.

4.“ATdataType?\r”

This command is a string and used to get the current data type.

When this command runs successfully, and the current data type is row data, then "Type:R\nOK\r\n" will be returned.

When this command runs successfully, and the current data type is heart rate, then "Type:H\nOK\r\n" will be returned.

This command can not run successfully when the “ATstartRead\r” is running.

5.“ATtestCon\r”

This command is a string and used to test the connection of the ECG cable.

When the hardware connection of ECG cable is ok, “OK\r\n” will be returned.

When the hardware connection of ECG cable is not ok, “ERROR\r\n” wii be returned.

6.“ATstartRead\r”

This command is a string and used to get the data from UART.

When the hardware connection of ECG cable is not ok, “ERROR\r\n” wiil be returned.

When the hardware is ok, “OK\r\n” will be returned firstly, and then the data will be transported continuously as soon as the data itself is updated. Both row data and heart rate are 8-bit hex values.

7.“ATstopRead\r”

This command is a string and used to stop the reading action through UART.

When this command runs successfully, “OK\n\r” will be returned and the reading action will stop.

Useful Link

nRFToolbox.apk