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Body temperature sensor

Mohmmad Safdar Vahora
Prodigy 10 points
Other Parts Discussed in Thread: TMP112, TMP007, TMP006, LMT70

Hello, I am working on the project of bio-medical parameters measurement system using arm controller.

I want to get the details about the body temperature sensor which would give me accurate measurements up to 0.5 degree centigrade.

I also want to obtain the details about the blood pressure sensor and ECG sensor.

With Regards,

Mohmmad Safdar Vahora 

  • 0
    TI__Expert 7945 points

    Hello Mohammad,

    Thanks for looking into E2E for product recommendations. TMP112 is perfectly suited for body temperature measurement within 0.5degC. Its one of the most widely used parts in the industry, specifically designed to cater health & fitness markets.

    If you are looking for a contactless temperature sensor I would also look into TMP007, while obtaining accuracy <1degC is possible with TMP007, obtaining accuracies <0.5degC may require calibration of individual units.

    For more information of Blood pressure sensors and ECG sensors please look into the following application diagrams, they will take you directly to the part numbers once you click on the appropriate application block.

    http://www.ti.com/solution/blood_pressure_monitor

    http://www.ti.com/solution/ecg_electrocardiogram

    Hope this helps!

    Best Regards,

    Abhi

  • 0 in reply to Abhishek Muppiri
    Prodigy 10 points

    We need a system for monitoring body temperatures preferable on a wearable device that is connected via WiFi.

    What do you recommend? Or who should we contact?

    Thanks,

  • 0 in reply to Lon Whelchel
    TI__Genius 15760 points

    Hi Lon, 

    What you mean with body temperature? ...Skin temperature?

    For a fitness watch, if you are looking for accuracy of around +/- 0.5C I will say you can give TMP112 a try. I know there are fitness watches on the market that measure skin temperature using TMP112. This recommendation is based on skin body temperature purpose which has no relevance to core body temperature.

    Here you have some hints/ideas that can be helpful:  

    Hope this helps!

    Mayrim

  • 0 in reply to Mayrim Verdejo
    Prodigy 105 points

    Hi Mayrim

    Your solution looks great to conduct the heat from skin to TMP112. But I'm wondering about the ESD performance. This solution sounds like extend the GND pin of TMP112 to a big matel pad so that end user can contact GND pin easy. Does this cause ESD problem?

    Regards

    Alex

  • 0 in reply to alex xu2
    TI__Genius 15760 points

    Hi Alex,

    Yes, your ESD concerns are valid but this is something that can be addressed with on-board system components such as ferrite bead capacitors. You can perform a power-on ESD test to verify your concerns. 

    Best Regards,

    Mayrim

  • 0 in reply to Mayrim Verdejo
    Prodigy 105 points

    Hi Mayrim

    Thanks for your support. Could you please share me a typical design to solve possible ESD issue for reference? My target is to pass the 2000V in HBM mode.

    Best regards

    Alex

  • 0 in reply to alex xu2
    TI__Genius 15760 points

    Alex,

    I haven't done this on the past. I will try to get some inputs from the power team. I will share any information I find. 

    Mayrim

  • 0 in reply to Mayrim Verdejo
    Prodigy 105 points

    Hi Mayrim

     

    Thanks for your kindly support. Waiting for your further information.

     

    Regards

    Alex

  • 0 in reply to alex xu2
    TI__Genius 15760 points

    Hi Alex,

    I shared this information with the ESD experts. Please find their recommendations below:

    Note: Assumption here is that the ESD energy is coming from the back ground plane. The ADD0 pin is connected to the PCB ground on the IC side (TMP112) and it is also connected to the large back ground on the other side of the ADD0 PCB trace.

    Possible external ESD protection configurations for the ADD0 pin.

    1. Back ground plane – TVS diode ( 5~6 V breakdown) to ground – PCB ground – ADD0 pin
    2. Back ground plane –  inductor or ferrite bead – PCB ground – ADD0 pin : if inductance is allowed on the ADD0 trace
    3. Back ground plane – TVS diode ( 5~6 V breakdown) to ground –  inductor or ferrite bead – PCB ground – ADD0 pin : if inductance is allowed on the ADD0 trace, better performance than other two options.

     Another key point is the PCB layout.

     - Connection 1: connection between the back ground plane and the PCB ground

     - Connection 2: connection/trace between the back ground plane and the ADD0 pin

    It is important to have the impedance of the connection 1 to be much lower than the connection 2 impedance to protect the ADD0 under any potential ESD condition.

    Hope this helps!

    Mayrim 

     

  • 0 in reply to Mayrim Verdejo
    Prodigy 20 points

    I am doing a project and it's a non-contact measurement of human body (especially ear temperature).
    Can I use the TMP006 sensor ?

    Kamil

  • 0 in reply to Mayrim Verdejo
    Prodigy 105 points

    Hi Mayrim

    Thank you very much for your kindly support. I need some time to understand your external protection methods. Will turn to you if I meet further problem. The key point on PCB layout looks great. Thanks a lot.

    Regards

    Alex

  • 0 in reply to Kamil Madej
    TI__Genius 15760 points

    Kamil,

    We recommend the part be used for relative temperature tracking but not for any medical diagnosis where accuracy is critical. If you are thinking on using a non contact measurement we would recommend TMP007 over TMP006. 

    Best Regards,

    Mayrim

  • 0 in reply to Mayrim Verdejo
    Prodigy 240 points
    can u pls. let me know if any specific metal is recommended to touch the skin and the PCB to get the tmp112 give the temperature output
  • 0 in reply to JAGANNATHAN g
    TI__Mastermind 30910 points

    Hi,

     

    In general, any metal should be fine since the thermal resistance is low.

     

    Regards

    Guang-Apps Sensing Products

  • 0 in reply to Guang Zhou
    Prodigy 45 points

    Guang,

    We are debating between TMP112 and LMT70 for temperature sensor.  The application is to measure body (skin) temperature.  Which is better sensor for this application?

    Thanks,

    Todd

  • 0 in reply to Todd Gun
    TI__Mastermind 41255 points
    Todd,

    These devices are very different.
    LMT70 has higher accuracy.
    TMP112 has a digital interface which is less susceptible to EMI.
    LMT70 may require a pricey ADC.
    LMT70 is smaller, and offers the fastest thermal response.
    TMP112 has a lower average current, but they are very close.

    Ren
  • 0 in reply to Ren Schackmann
    Prodigy 45 points
    Hi Ren, we are using Nordic nRF52832, which has built-in 12-bit ADC. Do you have any thoughts or experience working with these 2 ICs? Thanks.
  • 0 in reply to Todd Gun
    TI__Mastermind 41255 points
    I don't have experience with Nordic nRF52832.

    Ren