• Hi all,

    I am thinking about an application with Puck.js to detect if people is passing a corridor. I have a pretty high level idea that would like to know if this could ever work:

    A basic drawing of the design is:

    Wall Wall
    | |
    | |
    | Puck ) ||| <- Mirror
    | |
    | |

    The puck will emit IR signals (maybe with a ) and try to detect if the IR is reflected by the mirror to indicate the passage is unobstructed and if someone passes by we can detect the loss of signal.

    The system can be turned on using Bluetooth.

    What do you think? An obvious question is, is it possible to direct the IR trasmission from the Puck to not get directly caught by the receiver? Or else some kind of distance measurement (or delay) will have to be in place to distinguish reflected and direct signals.

    Best regards!

  • It might work - you could definitely give it a try. However you may fall foul of Puck.js's relatively limited IR transmission range (which is only maybe 1M - depending on how good the receiver is).

    Another option might be to use a red laser (and lasers are obviously cooler anyway) and then point the reflection back at the Puck's red LED (which is what is used for measuring light).

    Or... you could cheat and use something like: http://www.espruino.com/Pyroelectric

    They'd need another source of power but they are pretty efficient so would run for a while on a battery.

  • Thanks for your feedback Gordon! I will try this options :)

  • Wed 2019.12.04

    Hi @user106332 it appears range is something that is desired. Have you considered a low cost module like this - Radar RCWL-0516 (haven't tested and not sure of hookup for your project requirement)

    Wasn't able to find the YouTube video demo link. If I do, I shall post . . . .

  • Andreas Speiss has one video

  • Hi all :)

    Thanks for the feedbacks. I'm actually only require a pretty short distance in my use-case... And don't want to make it to sensitive to surrounding/far-away objects. I guess the lazer/short range PIR is the way to go...

  • Since your installation is stationary, IR optical works perfect: just put a decently adjusted reflective sticker on the wall/gate post/or what ever is on the opposite side of the sensor (transmitter and receiver). ...and to make the count reliable, place more than one on different heights and 'widths'
    and use some smartness to detect flailing arms or legs of tall people or alike.

  • Yeah good point. Actually the complete usage is more of a cheap "entrance control" than people counting... Basically if someone pass the check point without access rights, the checking mobile phone (fixed at the gateway) will raise an alarm. In order to get access, the user has to provide a valid QR code (from their phone) to the stationary checking mobile phone and that will disable the alarm for the next person passing. It isn't intended to be a strict check, just would make people opt to scan and track their presence.

    My use-case is at gym without a fixed front desk, but there would be people (and admins) around when the system is turned on.

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Proof of concept to use a single Puck to detect people passing a corridor with IR emit/receive

Posted by Avatar for user106332 @user106332