Sign in / Join
sensing techniques

How to Design for Reliable and Accurate Presence Sensing

Presence sensing

Consumer and industrial systems are growing smarter every passing day. They have become more interactive and autonomous. Owing to these developments, there is a need to empower them so that they are able to sense the presence of objects, passer-by or users. There are numerous basic sensing techniques that are well established that are already in the market. However, there is a growing demand for more accurate, cost-effective reliable and efficient presence sensing methods.

Factors that affect the performance of presence sensing systems

Presence sensing systems’ performance is dependent on numerous application specification issues like;

  • Size of the target object
  • Material
  • Consistency
  • Power requirements and available power
  • Confinement and consistency of the situation
  • Packaging and placement requirements
  • Physical mounting and ruggedness

Presence sensing approaches

There are three widely used approaches that are used for presence sensing. They include;

  • Optical sensing
  • Ultrasonic sensing
  • Inductive proximity principles

Radar is also used for sensing but it has complex RF design issues besides regulatory concerns as well. The video-based approach of presence sensing is also a possible option but it requires complicated signal processing and algorithm development making it quite costly.

Design considerations when selecting a presence sensing system

  • Beam Width
  • Distance from the sensor to target object
  • Interference
  • Consistency
  • Physical abuse
  • Environmental setting
  • Power requirements
  • Long-term reliability
  • BOM cost and of installation

How to improve presence sensing

The use of multiple sensors improves the accuracy and reliability of the presence sensing system. These sensors could be of the same or of a different type depending on the system priorities. For instance, if the primary goal is to ensure that no real target is missed, then parallel sensors could be used for overlapping coverage so as to implement the OR approach. If the primary goal is to ensure that no cases where an object is detected when there is actually no object at all, the multiple sensors could be used in series so as to implement the AND approach.

The AND and OR functions can be implemented in two ways. One is by hardwiring the outputs if they are compatible. The other way is by use of the software. Software approach is more flexible and allows the use of different algorithms to filter individual signals

You May Also Like This :”Low Power Revolution in Sensor Design

Start with optical sensors

Optical sensors employ the use of infrared to determine presence. An optical sensor is made up of an emitter and receiver that are mounted opposite each other across the area of interest. The two can also be co-located using mirrors. Co-location simplifies installation and wiring while doubling the optical path length.

Optical sensors are ideal for controlled and constrained environments. They can detect down to a few millimeters and are able to sense small objects across an area of tens of meters. More importantly, optical sensors use optical fiber hence their electronics can be located at a considerable distance from the optical window of the receiver and emitter.  This way only the fibers, which are relatively rugged are exposed to the harsh environments.

Use inductive proximity for ferrous sensing

Ferrous materials are sensed better by use of inductive proximity sensors. Inductive proximity sensors are better suited for detecting small ferrous objects at close range. It a non-contact, magnetic-based sensor that can be housed in a rugged non-metallic housing. There are numerous ICs that can be coupled with inductive coils making the design of such systems simpler, for instance, the LDC0851.


Part of improving prescience sense is understanding the various approaches that exist in the market. This will help you pick that which best suits your application. As a designer, you may also need to factor in issues like operating environment, consistency of target and ambient conditions.




  1. pregnancy belly oil 11 November, 2020 at 20:54 Reply

    What i do not realize is in fact how you’re no longer really a
    lot more smartly-liked than you might be now. You are so intelligent.
    You recognize therefore considerably when it comes to this subject, produced me
    individually believe it from so many numerous angles.
    Its like men and women aren’t involved unless it is one thing to accomplish with Lady gaga!
    Your personal stuffs nice. At all times care for it up!

  2. Vitamin C serums 14 November, 2020 at 23:35 Reply

    Pretty portion of content. I simply stumbled upon your site and in accession capital to say that I get actually loved account
    your weblog posts. Any way I’ll be subscribing in your augment and even I achievement you access consistently fast.

  3. dark circle 17 November, 2020 at 22:36 Reply

    Hi I am so thrilled I found your site, I really
    found you by mistake, while I was looking on Google for something else, Anyhow I am here now and
    would just like to say cheers for a tremendous post and a all round exciting blog (I also love the theme/design), I don’t have time to read through it all at the moment but
    I have bookmarked it and also added in your RSS feeds, so when I have time I will be back to read much more,
    Please do keep up the superb b.

  4. remove dark spot 17 November, 2020 at 23:24 Reply

    Good post. I learn something totally new and challenging on blogs I stumbleupon everyday.
    It’s always exciting to read through content from other authors and use something from their sites.

  5. kolkata escorts 20 November, 2020 at 22:57 Reply

    Thanks on your marvelous posting! I really enjoyed reading
    it, you may be a great author. I will be sure to bookmark your blog and may come back from now on. I want to encourage that you continue your
    great writing, have a nice morning!

  6. stretch arks guide 27 November, 2020 at 20:04 Reply

    I have to thank you for the efforts you’ve put in penning this blog.
    I am hoping to see the same high-grade blog posts from you in the future as well.
    In truth, your creative writing abilities has motivated me to get my own website now 😉

Leave a reply