AFE4400 - Only as HRM

Ashutosh,

We have received your post and hope to respond soon.

Hi Amy,

Any update on this?

Ashutosh.

1. Can I use ANY IR photo diode and IR photo transistor to interface with AFE4400? I know there is recommended list for such devices, but has anyone tried out others?

We do provide a list of recommendations, but some users have been successful with other sensors.

2. Can I use a Ear lobe sensor - normally used for heart rate monitoring to interface with AFE4400?

We have seen some users do this, so yes it is a possibility.

3. Which ADC registers I need to read to give to algorithm which calculated Heart rate? 0x2A to 0x2F? But which one are used to extract ONLY heart rate?

You will need to read the ADC Codes of 6 registers. 0x2A to 0x2F. Depending on which LED you are using, that is the one you will need to extract HR.

4. Is there any specialized algorithm to calculate heart rate or method described in Q18 of

We do not provide algorithms, but do supply sample code that can be found in out product folder.

5. I am connecting the IR Photo LED and photo transistor as per the schematic for EVM and block diagram is attached, is it correct?
The photodiode is backward. I included some e2e posts that may be useful.

e2e.ti.com/.../270665

e2e.ti.com/.../285068

Hello Amy,

Thanks for your reply, that clarifies most of the points but not solved i can say.

Especially point 3, HR monitoring will use only 2 LEDs IR LED and Photodetector. And other LEDs will be used for Oxymeter which is not part of my current implementation.

So if I am using only IR LEDs, which ADC ports needed to be read for processing HR monitoring?

Is there any documentation available for sample code? Which I can refer and know more details about it?

I will go through the posts you have mentioned.

Thanks,

Ashutosh.

You will need to read the value of the LED that is connected to IR (typically it will be LED1, but double check your implementation). We do have sample code to help you with this, it can be found on our product folder under tools and software.

www.ti.com/.../toolssoftware

Hi Amy,

Thanks for the update and information, i will go through this in detail and get back to you.

I have another question regarding using EVM for AFE4400, for this EVM there is no support to purchase the cables with IR LED and receiver to test with. How I need to test this EVM without these LED connections?

Do I need to build on my own or is there another part of cable which I can interface with this AFE4400 EVM?

Please let me know your comments.

Thanks,

Ashutosh.

Hi Amy,

Any update on this?

Thanks,

Ashutosh.

We do not have cables for the AFE4400 EVM except for the DB9 finger flip that was included. If you look at our later generation AFE4403 and AFE4404 EVMs we started including cables that could help with your application.