MAX30001 EV Kit (ECG, BioZ, Heart Rate, and Pace) - Review

Table of contents

RoadTest: MAX30001 EV Kit (ECG, BioZ, Heart Rate, and Pace)

Author: gordonmx

Creation date:

Evaluation Type: Development Boards & Tools

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: I haven't check out any alternative at this time, but Analog Devices has some app notes

What were the biggest problems encountered?: Poor documentation. Hardware was very robust.

Detailed Review:

First off, I would like to thank Maxim Integrated and Element 14 for the opportunity to evaluate the MAX30001 evaluation system.

 

Summary Conclusion –

 

As mentioned in the body of my review, the MAX30001 evaluation system (MAX30001WVSys) is very flexible board for experimenting with the many features of the analog front end (AFE) targeted for the medical market.  Its low power mode makes it a great choice for the portable/wearable market.  There is much to explore with the MAX30001, but for now here are of my conclusions on the evaluation kit itself.

 

Pros –

  • The system connection is very simple once you track down a few poorly documented details (see Cons).
  • It is very robust and stable for the sensitivity of the AFE.
  • Very low standby power mode.
  • The main board is loaded with many accessible test points (over 30 including ground points) and configuration jumpers (over 38) to add to its flexibility.
  • Very few external components are needed to use the MAX30001.
  • Maxim Integrated support team would response quickly (within 4 hours) to most of my questions.

 

Cons –

  • The documentation is very poor which may cause the user to have to spin their wheels a little more than necessary to get the kit to work.  Some of the issues were clearly Maxim Integrated (MI) issues, like a resource information card with the wrong URL for the GUI software or not putting the GUI software in a logical place.  Other communication issues may fall more on my side for not being as familiar as I thought with the medical side the measurement leading to a slower learning curve.
  • The system is useless without the proper electrodes to connect to the cables included with the kit.  Yet the kit does not include even 1 set of electrodes (3 electrodes per set are required). In addition, the documentation does not include any recommendations or specification for the electrodes.  I had to contact MI support for an answer.
  • The documentation is very limited.  The circuit schematics in the datasheet are size D drawings reduced to a size A manual page.  The printed drawings were unreadable.  It would have been nice to download actual drawings.  It would also be nice to have a copy of the microcontroller code to see know it interfaces to the MAX30001.
  • I had initial driver troubles connecting the kit to my Windows 7 PC.  Neither the datasheet nor MI support had a clear answer. I finally found the answer, but it took a few days.
  • Again I hate to beat on the documentation, but the datasheet (the only piece of documentation for the kit other than a demo video) offered very little help in configuring the board for each measurement.

 

Aside from improving the documentation, I have 2 other suggestions:

  • One area where Maxim Integrated could expand upon with the MAX30001EVSys Kit is with the MAX32630FTHR’s Bluetooth capability.  To highlight the MAX30001’s portability and wearability features, the microcontroller could have an option to communicate via Bluetooth to the PC, tablet or phone.
  • I know this is a demo board and not an actual development kit, but please include a MAXREFDES100HDK programming adapter and access to the MBED source code for the eval kit.  This would make it easier to see how to interface to the MAX30001 and work on the prior item.

 

Useful Document Links-

Maxim Integrated (MI) Tutorial 4693 – Introduction to Electrocardiographs

(https://www.maximintegrated.com/en/app-notes/index.mvp/id/4693)

MI MAX30001 Evaluation System Datasheet

(https://datasheets.maximintegrated.com/en/ds/MAX30001EVSYS.pdf)

MI MAX30001 Datasheet – Ultra-Low-Power, Single-Channel Integrated Biopotential & Bioimpedance AFE

(https://datasheets.maximintegrated.com/en/ds/MAX30001.pdf)

MI MAX32630FTHR Application Platform

(https://datasheets.maximintegrated.com/en/ds/MAX32630FTHR.pdf)

 

Part I – The Unpacking:  8^) with a little 8^(

 

Welcome to the first part of many of my evaluation of the Maxim Integrated MAX30001EVSYS evaluation kit: The Unpacking.  I have read many different views on the value and/or Importance of the unpacking segment, but I feel it is important because it is often our first glimpse into what to expect in the product and support.

 

I’m excited to RoadTest the MAX30001 evaluation kit, mostly for the analog front end (AFE), but also for the size and completeness of the design that makes it suitable for wearable designs. From the datasheet, one of the pluses to this board and software is the flexibility to change system/performance setting.  The eval kit is currently available through a couple of distributors, so one would expect the product would be easily setup and evaluated.

The box arrived undamaged, always a good sign, and well packed.

 

I was greeted with a thank card with details for product downloads and support on the back.

The content included just what was stated on the datasheet:

1 – MAX30001 EV Board, 1- MAX32630FTHR Cortex-M4F Microcontroller Board, 1 – USB Cable and 3 – ECG Cables. The microcontroller comes already mounted to the MAX30001 board and sealed in an anti-static bag.

 

The board assembly shows the microcontroller board (MCB) located in the lower left side of the main MAX30001 eval board.  The kit interfaces to the PC through the USB cable connected to the MCB for power and data transfer.  Aside from the MAX30001 itself and a few passive components, most of the main board consist of jumpers and test points, which adds to the configuration flexiblilty of the kit.

 

The heart of the evaluation kit, the MAX30001, is located at the center of the main board, while the microcontroller is attached by a socket in the upper left hand corner (see pictures)

   

Now for a few of the drawback I have observed –

 

1) The GUI software download link is incorrectly given on the information card included in the kit. The card shows the link as www.maximintegrated.com/EVkitSoftware , but actually https://www.maximintegrated.com/en/design/software-description.html/swpart=SFW0005070A.  The software is not located on the EV kit page, but on the base MAX30001 component page under Design Resources -> Software.  To only make things more confusing, the datasheet lists the file name as MAX30001EVKitSoftwareInstall.ZIP, when the download filename is MAX30001GUISetupV310.zip.  NOTE:  I did enter a support tag for finding the software and Maxim did reply in about 4 hours.

 

2) In order to run the demo you need to have electrodes to connect to the ECG cables.  The electrodes are not included in the kit.  So before you can evaluate the ECG functionality, you must order electrodes, but which type?  I assume disposable electrodes will work, but the documentation doesn't specify the typeNOTE:  I have entered a support tag to answer this question and Maxim did reply in about 4 hours.  Therese Montgomery, Maxim App Engr, suggested ordering the 3M Red Dot electrodes from Amazon.

 

3) There is very little supporting documentation for the hardware.  As an example, the only schematics are D size documents reduced to an A size manual pages. The drawings are too fuzzy to read.

 

4) To go along with item #3, at a very basic level the overall assembly is similar to an mbed-based controller (i.e. MAX32630FTHR) with a MAX30001 shield.  It would be helpful to have access to the controller code to see how it interfaces with the MAX30001.

 

Part II – Installing The GUI Software:  8^(

 

Following the instructions in the EV kit datasheet, I started part 2, software installation and immediately ran into a problem.  My host PC is running under Windows 7 x64.  The documentation states the standard USB driver on Win 7 should work, but when I plugged the EV board into the PC USB port it couldn’t find a driver and the following window appeared:

 

I googled "Win 7 CDC USB driver" and found many, but which was the correct driver.  Another email to the Maxim Integrated support team yielded a response to make sure my Windows OS had all the latest updates (I already had). This was not the fix.  NOTE: The “good” news is the support team usually replied within 4 hours to my requests.

 

The Host PC interfaces through the pre-programmed MAX32630FTHR microcontroller, which if I understand the documentation correctly, is running under a MBED OS.  The USB port is supposed to be setup as a virtual serial console (HID device) and uses the CDC serial driver.  But this assumes the microcontroller is running a MBED OS and connects as a serial device.  This is when I wish they had included a MAXREFDES100HDK programming adapter to explore the microcontroller a little better.

 

I was also hoping another road tester would have seen the same problem, but I guess I’m the only one.

 

But all this was a moot point since I solved the problem before anyone else replied.  Then I only had to wait until I get my electrodes (~01/26) arrived to completely check the solution.  As previously mentioned, when I plugged in the board to the PC, I would get a “CDC DEVICE – No driver found” message so I was looking for a USB communications device class (CDC) driver.  My past experience would say this would be a serial driver.  Particularly a MAX32630FTHR serial driver.  Have you ever read something over and over again only to miss a point because you were expecting something else?  After re-reading the install section multiple times, I finally noticed the followed “The USB interface of the EV kit hardware is configured as an HID device …”.  The EV does not use a serial, but a HID driver.  Under the Windows device manager, I opened the failed CDC device and updated the driver using a Microsoft HID-Compliant consumer control device driver.  The PC then recognized the EV kit.  I then installed the GUI software which assigned it a USB port.  (See pictures below)

 

Since the microcontroller isn’t a MBED device, it will not appear as a USB drive.

 

Steps to load the driver -

 

Plug in EV board

Click Update Driver

Select “Browse my …”

Then select “Let me pick from a list …” -> “Human Interface Devices” - > “Microsoft” -> “HID-compliant consumer control device”.

When you click “Next” you may get the following warning, click “yes”

For the following response (successful)

 

The device manager window should show the new device.

You can now install the GUI software, which also start a device driver install wizard, which may also prompt another warning window.  Press “Install this driver software anyway”

After the GUI software has been installed the device manager windows should show the EV under “ports”

The GUI should also show the connection in the lower right corner.

 

Part 3 – Testing the Board:

Now the fun part, but first I must confession I thought I knew more about medical sensors than I actually did (or do).  I’m concerned that my ignorance will only become more apparent as I proceed, so please forgive me in advance.  Up until now I could safely say that some of the issues I have found could have been avoided with better documentation, but the setup of electrodes and measurement adjustments, although could be improved by the documentation, may not be as necessary for individuals with more familiarity with related medical equipment.

 

Some ECG Basics

ECG measurements can be performed using a 3, 5 or 12 electrode (E) setup.  The more electrodes the more detailed and accurate the results may be. For systems that use fewer probes, the electrodes locations may be moved around to make different measurements.  The MAX30001EVSys kit uses the 3E configuration, as might be expected for the wearable (i.e. portable) market.

 

The most common electrode placement for a 3E configuration is shown below:

  Source: “Lead Positioning” Life In The Fastlane2017 (https://lifeinthefastlane.com/ecg-library/basics/lead-positioning/)

 

The RA (white) electrode is placed under the right clavicle, mid-clavicular line within the rib cage frame. The LA (black) electrode is placed under the left clavicle, mid-clavicular line within the rib cage frame.

The LL (red) electrode is placed on the lower abdomen within the rib cage frame.

 

As the heart pumps, its main muscle generate an electric field directed from the upper right shoulder (RA) to the lower left leg (LL) and is picked up across the electrodes, much like a sensitive voltmeter.  The signal is very small and can be susceptible to many environmental conditions.  The LA electrode acts as a reference to improve the signal integrity.

 

A typical ECG waveform is shown below. I won’t try to explain what each peak or dip represents, but the main peak (R) is a result of the contraction. The MAX30001 measures the R-to-R interval for heart rate.

 

https://commons.wikimedia.org/wiki/File:ECG-PQRST%2Bpopis.svg

 

Back to the Evaluation Board

Very little information is given in the documentation to help setup the board.  I recommend before powering up your board, that you view the video on the EV kit website, paying close attention to jumper configuration, cable connections and software settings.  (https://www.maximintegrated.com/en/design/videos.html/vd_5644710620001#popupmodal)

 

Configure your board (if necessary) and connect your cables/electrodes before connecting to the USB port.  The electrodes I used (ordered thru Amazon) were the inexpensive 3M™ Red Dot™ Monitoring Electrode with Foam Tape and Sticky Gel 2560 for multi-purpose ECG monitoring.  Each consists of a form adhesive pad with a metal contact to connect the cable to. The contact is surrounded by a conductive sticky gel that comes in contact with the patient’s skin.

 

For ECG readings, the electrode cables should be connected to the board as shown below

  RA(white) to ECGN plug, LA(black) to BB plug and LL(red) to ECGP plug.  BB stands for body bias.

 

Next start the GUI program.  If you connect the board before starting the program, the GUI software should find and connect to the EVK automatically.  If not, follow the instructions on page 4 of the datasheet to connect.

 

The GUI should open in the Home tab.  Two other tabs are used for the ECG and R-to-R measurement setup: 1) ECG Channel and 2) ECG MUX, both shown below.

 

Aside from some passive components for ESD and simple filtering purposes, what is represented on these 2 tabs, are internal to the MAX30001 and completely configurable.  Very impressive and flexible.

 

Although you can configure the system manual through the GUI, the quickest way to setup up the board is using the “Quick Start Settings” under the Home tab.  For the ECG and R-to-R measurements highlight the “Run All(ECG, R-to-R, Pace, BioZ)” selection then press the [Apply Settings] button and deselect “EN_BIOZ” and “EN_PACE” under Channel/Plot Enable at the bottom left of the GUI.  Next go to the Plots tab and press the [Start Monitor] button. It is that simple and you should see the following output:

NOTE:  If you don’t get a periodic waveform check the following items 1) are both the ECGP/N switches in “Connected” mode {the default mode is Isolated}, 2) are your cables/electrodes connected properly {I didn’t have to shave my chest for the electrodes to work} and 3) is your hardware connected {check the lower right corner of the GUI}.

 

For BioZ (BioImpedance) readings, the electrode cables should be connected to the board as shown below

RA(white) to BIN plug, LA(black) to BB plug and LL(red) to BIP plug.  BB stands for body bias.

 

Three tabs are used for the BioZ setup: 1) BioZ Channel, 2) BioZ MUX and BioZ Load shown below.

   

Again very impressive and flexible.

 

The website video and the written documentation goes into very little detail about the board setup for the BioZ measurements.  Like the ECG setup you can configure the system manual through the GUI, but especially in this case the quickest way to setup up the board is using the “Quick Start Settings” under the Home tab.  For the BioZ measurements highlight the “Run BioZ Only” selection then press the [Apply Settings] button.  Before going to the Plots tab and pressing the [Start Monitor] button, you should go to the “Options” drop down menu and select “BioZ Milliohm Scale” to increase he sensitivity.  After pressing the [Start Monitor] button you should see the following output in response to my shallow breathing:

NOTE:  There are many things I did like about the kit (see conclusion), but I found particularly the fact that the main board is loaded with many accessible test points (over 30 including ground points) and configuration jumpers (over 38) to add to its flexibility, was very helpful.  All points and jumpers were clearly labeled.

 

 

What I didn’t try

I didn’t have a pacemaker or a pacemaker simulator so I couldn’t test this feature.  They do show the use of a pacemaker simulator in the video on the EV kit website (see above);

 

What if?? (Or What I’d like to see in the future)

  • One area where Maxim Integrated could expand upon with the MAX30001EVSys Kit, is with the MAX32630FTHR’s Bluetooth capability.  To highlight the MAX30001’s portability and wearability features, the microcontroller could have an option to communicate via Bluetooth to the PC, tablet or phone.
  • I know this is a demo board and not an actual development kit, but please include a MAXREFDES100HDK programming adapter and access to the MBED source code for the eval kit.  This would make it easier to see how to interface to the MAX30001 and work on the prior item.
  • Well, at least supply the source code 8^).

 

Please let me know if I missed something in the documentation.  Also please pardon my typos.

 

Gordon Margulieux

Meridian, ID USA

Anonymous