A Smartphone based Monitoring System (IoT enabled)

The most burgeoning questions in healthcare have found solutions in parts when internet-of-things (IoT) is applied to this industry. Cardiovascular conditions, among the chronic diseases in the United States, are the most prevalent and costly to manage.

Wireless devices such as smartphone are so ubiquitous that medicine is more personalized than ever. Innovative medical devices can be created once internet-of-things are connected to this tiny computer in the pocket

There’s money to be made: According to Medgadget, Internet of Things (IoT) Healthcare Market is Growing at 30.8% CAGR Dominated by Medical Device Segment

Which is good! As it will lead to affordable diagnostic and monitoring systems across the board and therapeutic areas. More on that in the later articles.

So let’s get to it!

IOT Infrastructure:  Smartphone Based System for Monitoring the Cardiac and Respiratory Systems

This article discusses Sohn, K. et al.‘s smartphone based diagnostic and monitoring systems that are accurate (when compared to a cardio lab system) and quite inexpensive. This is one of the major applications of how Internet of things (IoT sensors etc.) could be connected to a smartphone (or a wireless mobile device) for monitoring and diagnostic healthcare uses. It also discusses an application to assess underlying ischemia, and estimate the respiration rate (RR) and tidal volume (TV) from analysis of electrocardiograph (ECG) signals only.

The authors of this research paper developed a wireless cardiorespiratory monitoring system based upon just a smartphone and an electrocardiograph (ECG) device that was built using three commercially available components: an ECG module, a microcontroller board and a Bluetooth module.

The smartphone, named “cvrPhone,” estimates the ischemic state of a subject in real-time based upon 12-lead ECG signals that are transmitted from the ECG device.

The smartphone-based ECG acquisition system, or “cvrPhone”

Infographic: The smartphone-based ECG acquisition system, or “cvrPhone”

The Bluetooth-enabled ECG acquisition system is composed of three commercially available parts: an analog-to-digital (AD) converter, a microcontroller board and, a Bluetooth module.
(A) Flow-diagram of the 12-lead ECG signals from the torso to smartphone. Ten electrodes are placed on the torso for the recording of 8 ECG leads (Leads I and II and six precordial leads). The AD converter amplifies and digitizes the 8 ECG leads. Then the signals are transmitted to the smartphone through the HC-05 Bluetooth module, and the remaining leads (Leads III, aVR, aVL and aVF) are calculated. (B) Real-time display of selected three ECG signals on the smartphone screen.

Hardware Architecture

The ECG device is composed of:

Pin connections between the three parts

Pin connections between the three parts

Picture of the hardware

Picture of the hardware

• an Analog-to-digital (A/D) Converter (ADS1298, Texas Instruments): ($41) Cheaper ones on Amazon/EBay/Alibaba (from $3)

• a Microcontroller Board (Arduino Due AT91SAM3 × 8E) ($35): Cheaper ones from $5

• and a Bluetooth Module (HC-05, Guangzhou HC Information Technology Co., Ltd.): ($2.5-3  / Piece)

The AD converter amplifies and digitizes the analog ECG signal from electrodes and the microcontroller transmits the digitized ECG signal to the smartphone. Uninterrupted Bluetooth communication could be achieved up to 10 meters away from the smartphone

Microcontroller Software for most of Internet of Things Related Projects

  • Download the Arduino IDE : open-source integrated development environment (IDE) Arduino 1.8.5 (at the time of authoring this article) for the microcontroller programming
  • There are two main steps in the function of the embedded software (Supplementary PDF):
    • First, initialize the AD converter and the Bluetooth module
    • Second, transmit the ECG signals upon user’s request
Block-diagram of the microcontroller embedded software

Block-diagram of the microcontroller embedded software

Block-diagram of Android Application

Block-diagram of Android Application


  • Comparison of ECG Signals between the Smartphone and Prucka Cardiolab show the same ECG morphologies in all leads.
  • The estimated RR values mostly show excellent agreement with the real ones (R2 = 0.97912). In Fig. 2B, the tidal volume was changed randomly from 0–820 ml. The estimated TV values mostly show very good agreement with the real ones (R2 = 0.8517).

To-Do’s for Internet of Things Related Projects:

  • Start a project to build a diagnostic tool for Cardio-Respirtory System
  • Utilize resources such as Instructables.com
  • Utilize and modify (and contribute) open-source resources such as Git for software and algorithm related requirements

This article does not delve into the Institutional Review board approval requirements (IRB) or animal testing for testing this monitoring tool. For discussion on ECG processing algorithms, evaluation of results and further discussion, refer to the references.


1. Sohn, K. et al. cvrPhone A Novel Point-of-Care Smartphone Based System for Monitoring the Cardiac and Respiratory Systems. Sci. Rep. 7, 44946; doi: 10.1038/srep44946 (2017).

2. Supplementary information PDF Document

3. IoT Healthcare Market Growing at 30.8% CAGR Dominated by Medical Device Segment

Categories: Healthcare

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