AD8232 in Heart Rate Measurement next to heart configuration (Sports)

Hello everybody,
I was trying to make a Heart rate monitoring system for one of my home made sports project, I’m using Ad8232 Breakout board from Sparkfun electronics Link! ,This comes with the Three leads configuration mode, I was trying to make this in Two leads configuration mode same as shown in the Datasheet section of AD8232 in Application NOTE : Heart Rate measurement next to heart, I’ve also tweak down the components like removing the unwanted resistors and capacitors plus adding the jumpers to the Break out board while understanding the schematics from the datasheet. (Please look to the attachment for the schematics I’m using for my project)

AD8232 is able to capture only a little amount of signal (i can barely see the light blinking on the board) from my heart using Two electrodes (Eliminating Right Leg Drive Electrode) can anybody expert here spot my fault and tell me what to configure .
Please help.
Have a good day
Thanks

AD8232_Heart_Rate_Monitor_v11.pdf (74.5 KB)

Hi,
Did you try the three leads mode before modifying to two?
Which lead did you leave out?

Tom... :slight_smile:

I’ve also tweak down the components like removing the unwanted resistors and capacitors plus adding the jumpers to the Break out board while understanding the schematics from the datasheet.

What does that mean ?
What unwanted resistors and capacitors ?

while understanding the schematics

Understanding WHAT ? (about the datasheet)

Just how much electronics experience do you have anyway ?

If you are going to refer to the datasheet you should link it separately as well.

Thank you for the reply

@TomGeorge ,Yes I’ve tried with the Three leads Cardiac mode before started tweaking it to Two leads, It’s working in the Three leads mode. I’ve eliminated Right Leg Drive Lead.

What does that mean ?
What unwanted resistors and capacitors ?

SparkFun AD8232 Breakout board Link to the board This board is in Cardiac monitoring configuration which uses 3 electrodes to capture the signal, where as this board can be configured to 2 Electrodes only for Sports application. There’s a schematics in the datasheet in the application circuits page number 24 " Heart rate measurement next to Heart" they only used fewer components and removed unwanted ones.

I’ve a good experience in electronics and I’m sorry for not attaching the datasheet, Here it’s Datasheet

I know this is a very old post. But @mudassir9999, did you get any further on solving this problem? I'm working on something similar

This sounds like a typical exercise in "creative head-banging".

The fundamental problem is failure to comprehend the requirement for total isolation of the circuit using the ECG "front end". The person to whom it is connected must be not in contact with or near to any other equipment or electrically conductive structure and you require complete isolation of the electronic module. This means it must be battery powered, not connected in any way to any mains power or even mains ground or grounded structure.

Obviously professionally-designed equipment contains isolation devices sufficiently engineered and certified to permit connection to other equipment, generally nowadays by a USB cable.

The only way you can consider a measurement with two wires is where the complete device is contained in a unit no larger than a cigarette packet and strapped to the subject - no other connections at all. A minimum of three wires (for a "single ECG lead" monitor) is used in all clinical applications.

Note however that the "right leg drive" connection does not necessarily have to connect to the right leg! It is only required that it be a reasonable separation from the two measuring connections.

I am not sure what is meant about dispensing with "unwanted" components. Obviously you cannot omit any of the components connected to the sensing wires.

Paul__B:
I am not sure what is meant about dispensing with “unwanted” components. Obviously you cannot omit any of the components connected to the sensing wires.

Thank you for all the info on ECGs! To explain the question more completely - Sparkfun provides the schematic for their AD8232 breakout board here: https://cdn.sparkfun.com/datasheets/Sensors/Biometric/AD8232_Heart_Rate_Monitor_v10.pdf

This is based off page 25 of the AD8232 data sheet here: https://www.analog.com/media/en/technical-documentation/data-sheets/AD8232.pdf

We wonder whether we can modify sparkfun’s board to create the circuit described on page 24 of the AD8232 data sheet:

We see that there are more components on the page 25 implementation and wonder if we can remove the “unwanted” components to produce the circuit on page 24.

I do hear what you’re saying about the isolation and interference… Would the page 24 circuit be ruined if it were in a battery-powered, cigarette-box-sized container with a Wifi module? Would the RF from the WiFi affect the readings? Thank you again for the pointers.

Well, you have read the information you have quoted; while I did not find it before (as I don't think it was part of the original link), it appears to be exactly what I described.

If it is a small container with the electrodes attached to it and strapped to the chest with no other leads or connections, the simplified circuit can be used but will not be as reliable.

WiFi may or may not interfere with the readings, not so much because of the RF but because an ESP8266 generates substantial erratic impulses on the power supply. You might need either to not record whilst engaged in any WiFi communication with a few seconds separation, or use a second battery for the two sections.

How do wireless monitors in hospitals work, you might ask? They would be using continuous carrier with FM or a continuous pulse stream at a high frequency.