Integrating Sensors: A Doc-on-a-Chip? Part 1

Many companies are working on a set of biomedical sensors with wireless communications capabilities for sensing body temperature, heart rates, breath rates, intraocular pressure, CO2 concentration, and several other constants and parameters to individuate disease attack preludes. These projects are focused on real-time patient monitoring, so the system can automatically send alarms to a remote healthcare center, family members, or even the patient's mobile phone to advise a rescuer about mitigating actions.

The idea of integrating much of the functionality of a system-on-chip (SoC) has been around for some time. Nowadays it's very interesting for real-time medical monitoring. Some companies, including mine (STMicroelectronics), are working on integrated systems that incorporate many sensors to measure parameters that are useful in revealing a disease or dangerous condition in a patient.

In a blog post on Medical Packaging Innovation (a sister site), Adele Graham-King tells us that breath-acetone is an indicator of glycemic control in diabetics. Acetone concentration can be measured by means of some integrated silicon-based gas sensors. The sensors can communicate with a smart device via Bluetooth or more generally in a wireless mode.

The receiving device can also store the data coming from the patient and communicate with a medical center, which can manage emergency situations, for example. The sensors can be placed in a macro package that is applied directly on the patient's body. The basic idea is to ensure a low bit error rate in the communication and to secure the data stored in the device to make sure that only authorized personnel can access it.

The gas sensors are not the only silicon-based devices being engineered for these types of applications. For example, MEMS sensors can convert a pressure reading into an electrical signal. This can then be conditioned (to reject the noise), amplified, and converted into digital form. These systems basically present a piezoelectric effect in the direction of the mechanical stress, as showed in Figure 1.

Figure 1

MEMS gyroscope principle of operation.(Source: MEMS CENTRAL)

MEMS gyroscope principle of operation.

MEMS sensors can be utilized to measure a patient's blood pressure and heart rate. Such an integrated system is based on the Internet of Things approach: an SoC containing silicon-based gas and pressure sensors and a communications section. These can communicate with a smart device able to store and process the data coming from the patient and to send alarm messages as needed. This will produce truly real-time patient monitoring.

In the next part of this series, we will see what else these integrated devices could do as part of a diagnostic SoC.

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14 comments on “Integrating Sensors: A Doc-on-a-Chip? Part 1

  1. amrutah
    December 14, 2013

    Paolo: Thanks for the post for sharing the usage of silicon devices in medical field.

    “These can communicate with a smart device able to store and process the data coming from the patient and to send alarm messages as needed”.

         Truely this will be a real-time monitoring of the patient health.  Smart devices here means smartphones/phablets/tablets, or will these be a new set of handheld devices for doctors?

  2. amrutah
    December 14, 2013

    @Paolo: “Acetone concentration can be measured by means of some integrated silicon-based gas sensors”

       I read through the article that you shared and its interesting to know about the breath analyzer.  The ketones that are released during hyper-glycemia conditions add to the body fluids and subsequently gets added to the breath (basically to the water contents of breath).  Does these gas sensors detect only the gas or fluid contents of a gas?  

    It will be very helpful in understanding the silicon-based gas sensors if you can share any documents or datasheets…

  3. amrutah
    December 14, 2013

    ” These projects are focused on real-time patient monitoring, so the system can automatically send alarms to a remote healthcare center, family members, or even the patient's mobile phone to advise a rescuer about mitigating actions”

       Yes this will be very useful enabling programmed non-invasive or minimally invasive drug administration till the doctor appears on scene.  Basically in the patients suffering from Diabetes slow non-invasive adminitration of insulin can be done.  Also in Kidney related infections where the creatinine levels are monitored drug administration can be done to avoid damage to kidney.

  4. Davidled
    December 14, 2013

    In the health monitoring system, question is how to implement MEMS sensor for each patients from body to let customer believe the data in quality. Quality sensor makes smart devices.   

  5. Davidled
    December 14, 2013

    That is a little bit impact for insurance company as premium cost would be down. In other words, smart device as you comment would prevent and protect the patient big surgery case. I wonder how health insurance regulates this matter. So far, I believe that up to now,there is no any item related to drug administration using health monitor in the insurance company like smoking or non smoking.

  6. amrutah
    December 14, 2013


       I understand that the sensors (MEMS or any other) have to fit a wide range body characteristics so that the quality of the specification/parameter is within range and sensible.  However, the last sentence is unclear “Quality sensor makes smart devices ” sensor is inside the patients body while the smart device is the one through which the data is communicated (I thought its at the receiving end of the communication channel)

  7. etnapowers
    December 16, 2013

    @amrutah: Smart devices here means both smartphone/tablet device and a dedicated  device to store and manage the data, this will be better explained in the second part of this BLOG.

  8. etnapowers
    December 16, 2013

    The sensors detect the presence of stress indicators in the human breath, these sensors are medical integrated sensors for medical application, an example is this gas sensor

  9. Netcrawl
    December 16, 2013

    @Daej I agree with you about this, sensors have become much smaller, getting much more sophisticated and low power in the last few years, driven in part by MEMS revolution, unfortunately the overall cost of installing sensors has not kept pace, it still an expensive stuff-the cost of installing wires could dwarfs the cost of sensor itself. Today's market want solutions that is low cost and easy to deploy, receives periodic data reliably with no battery changes and low latency, its a serious issue for the whole industry.

  10. Netcrawl
    December 16, 2013

    @Daej you're there's a big problem here, that would in the quality of data, the reality is the wireless channel is unreliable and there's some number of phenomenom that can prevent a transmitted data packets from reaching its destination- interference, interference might come from other networks this can cost in delay in transmission and worst of all a possible transmission lost. 


  11. Victor Lorenzo
    December 16, 2013

    @Netcrawl, “the reality is the wireless channel is unreliable ” I agree with you. Wireless networks are error prone and may suffer from availability issues. But wired sensor networks can also suffer from sudden sensor connection failures. It's a normal feature in patient monitors to include sensor failure (or disconnection) detection circuits.

    I guess that extreme cases like patients requiring implanted defibrilators will continue being fully independent/intelligent units, using the wireless connections only for transmitting non-vital data, configuration and status.

  12. goafrit2
    December 16, 2013

    Lots of challenges because we are having a new dawn when we see there mobile devices taking over new assignments beyond phone calls and emails/SMS. The problem is standardization is not there. Imagine GE losing the opportunity of selling $200k ultrasound tool because one doctor can use his tablet to check up a patient. It could be totally disruptive if we get it right.

  13. amrutah
    December 16, 2013

    I completely agree, also this wireless channel being a short channel more error correction and redundancy can be added to reduce the failure.

  14. samicksha
    December 17, 2013

    If i look towards FCC, they oversee the use of the public radio spectrum within which RF wireless technologies operate, but before this i am curious to understand more on Electromagnetic Compatibility and on what parameters one should account QoS.

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