LMT70: LMT70 Temperature sensor wearable locations on human body

Naga Rajan61

Intellectual 320 points

Part Number: LMT70
Other Parts Discussed in Thread: TIDA-00824, TIDA-00721, CC2640R2F, TMP117

I am using LMT70 temperature sensor for measuring human body temperature.

What are the human body locations available to fix this sensor?

over 5 years ago

0 Audrey Dearien7 over 5 years ago

TI__Expert 4875 points

Hello Naga,

There are many locations available for measuring body temperature, but the choice will depend on your design constraints. As described in TIDA-00824 (which uses LMT70), both the wrist measurement and the under-arm measurement settle at the same temperature, but the under-arm measurement reaches the final temperature faster.

What are the constraints of your design?

Thanks,
Audrey

0 Naga Rajan61 over 5 years ago in reply to Audrey Dearien7

Intellectual 320 points

Hi Sir,
Instead of using watch type design, is it possible to wear it as a sticker type on human body?

0 Audrey Dearien7 over 5 years ago in reply to Naga Rajan61

TI__Expert 4875 points

Hi Naga,

Yes, it is possible to design the sensor onto a patch to stick onto the body as long as it makes good contact to the skin. Please refer to TIDA-00721 which is a TI Design for a temperature sensing patch. Additionally, the application note SNIA021A describes layout considerations for wearable temperature sensors for the human body.

Regards,

Audrey

0 Naga Rajan61 over 5 years ago in reply to Audrey Dearien7

Intellectual 320 points

Fine sir.

The TIDA-00721 temperature sensing patch using NFC application.

Is it possible to transmit the temperature data via bluetooth to a smartphone?

Can i use bluetooth Microcontroller chip to interface with LMT70 for this application?

Regards,

Nagarajan

0 Kelvin Le THS over 5 years ago in reply to Naga Rajan61

TI__Expert 6475 points

Naga,

LMT70 is an analog sensor. Once you have converted the analog output to digital you can choose whatever means to transmit wirelessly.

-Kelvin

0 Naga Rajan61 over 5 years ago in reply to Kelvin Le THS

Intellectual 320 points

Hi Sir,

I have interfaced LMT70 temperature sensor with CC2640R2F bluetooth MCU which has 12 bit ADC.

Will LMT70 sensor support 12 bit ADC type?

- Naga

0 Naga Rajan61 over 5 years ago in reply to Audrey Dearien7

Intellectual 320 points

Hi Sir,
Is it possible to increase the range of NFC communication between temperature sensing patch and smartphone?

- Naga

0 Audrey Dearien7 over 5 years ago in reply to Naga Rajan61

TI__Expert 4875 points

Hello Naga,

I apologize for the late response. We did not receive a notification for your follow-up question.

Yes, you can interface the LMT70 with the 12 bit ADC, or other resolution ADCs as well. However, you will need to consider your desired accuracy based on the quantization error of the ADC and other error sources like the reference voltage. The only way around these errors would be to utilize a digital temperature sensor, like the TMP117 which integrates the ADC in the temperature sensor IC.

Hope this helps.

Audrey

0 Audrey Dearien7 over 5 years ago in reply to Naga Rajan61

TI__Expert 4875 points

Naga,

Please redirect this question to TI's Wireless Connectivity e2e forum. They will be able to help you with this aspect of your design.

Regards,

Audrey

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LMT70: LMT70 Temperature sensor wearable locations on human body