ECG Logger - a Wearable Cardiac Monitor for Long-Term Data Acquisition and Analysis

ECG Logger is a Wearable Cardiac Monitor for Long-Term Data Acquisition and Analysis. The ECG Logger Project is aimed for providing a very low-cost (~35$) open-source hardware and software for a Rhythmic Holter. The hardware has been made very simple and is based on an Arduino Nano with two companion boards for the SD card and the instrumentation differential amplifier. It helps monitoring arrhythmia syndromes such as bradycardia, tachycardia, extra-systoles or pause. In no case it can be use to replace a professional medical examination.
ECG Logger Viewer is the companion software for reading ECG data from the ECG Logger device

ECG Logger is an affordable very low-cost (~35$) and simple ECG-Logger Holter offering a complete solution including a pocket-size ECG recorder hardware device with embedded firmware. The ECG signal is recorded onto a SD card memory at high frequency (250Hz sampling rate). The device is backed by the recent technology offering more freedom and accuracy for up to 24 hours continuous recording.

The system is based on an “Arduino Nano” microcontroller, an AD8232 Heart Rate Monitor amplifier board and a SPI SD card module with absolute minimum extra components

Features

Stable and reliable recorder, based on state-of-the-art and most recent technology
Anti-jamming and anti-shock
Small in size
Waveform record and event marking
Accurate start time record and sampled data
Built-in SD card for storage (can be plug-in and pull-out)
No need to compress original data, thanks to the large storage capability
Faster USB 2.0 interface
Record waveform details based on high precision and sampling frequency
Record the state of pacemaker using higher sampling frequency.
Automatic R-R peaks detection using Pan-Tompkins.
International standard of 3 leads. Record up to 24-hour of ECG signal.
Very simple and ergonomic user interface
IMPORTANT:
This project is Open-Source licensed for educational purposes only and none of its components can be used or reused for commercial purposes or applications.

USB driver must be installed on the computer prior to Holter (Arduino Nano) connection. Some Arduino use the FTDI chipset whereas some Chinese products require the CH340 chipset. The corresponding driver must be downloaded and installed on the computer. Click Start >> Control Panel >> Device Manager, and in the device list look for Com Ports (e.g. USB-SERIAL CH340).

Specifications

Number of Channels: 1
Lead:standard 3-lead
Sampling Rate: 250 Hz
Sampling Accuracy: 10-bit / 8-bit selectable
Recording Time: up to 24 Hours
Time accuracy: +/- 1 minute per day
Interface: USB 2.0 (230 kbauds)
Scale Voltage: 1 mV ±5%
Sensitivity valve: ≤20μV (TBC)
Lowest voltage signal: 50 μ Vpp (TBC)
Input Impedance: ≥ 1GΩ
Input circuit bias current: ≤ 0.1 μA
Noise level: ≤ 10 μ Vpp (0.1 Hz to 40 Hz)
Common-Mode Rejection Ratio: >= 60 dB (DC to 60Hz)
Electrode offset rejection: ± 300 mV
Voltage tolerance: ± 500 mV
Time constant: > 3.2 s (0.3Hz)
Frequency response: 0.05 ~ 150 Hz
Filter: AC, EMG, Drift Filter, RFI
Complex QRS detection: Pan & Tompkins algorithm
Safety Human Body Model: 8 kV ESD (HBM)
Physical Parameters:

Type B: internally powered
Size (L x W x H) : 100 x 60 x 25 mm
Net weight (w/o battery): 65 g
Weight with batteries: 111g
Total weight: 195 g (incl. carrier/electrodes)
Power: 4 x AAA batteries
Autonomy: >30 hours with Alkaline batteries
Average consumption:

Normal mode: 17 mA (Standby)
Sleep mode: 6.2 mA
Recording mode: 31 mA (~36 hours - depend on SD Card)”

Link

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