• Motion sensor that can "see" through glass

    From Chris Schram@3:770/3 to All on Thu Dec 23 21:53:27 2021
    I have grown more and more hard of hearing as I grow older. and I cannot
    always hear when someone is at the front door. I'm looking for a motion
    sensor that I can locate inside the front window.

    I have played briefly with an old Radio Shack infrared motion alarm that otherwise works fine, but can't "see" through glass at all.

    I also have a little Wyze security camera that can detect motion, but it
    seems way TOO sensitive to be useful.

    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

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  • From Axel Berger@3:770/3 to Chris Schram on Thu Dec 23 23:04:13 2021
    Chris Schram wrote:
    It would be used in some sort of RasPi or Arduino configuration.

    That might work, but it's a lot of hassle and complication. The doorbell already is an electric signal. Could you not use that directly?


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  • From Lew Pitcher@3:770/3 to Chris Schram on Thu Dec 23 22:29:06 2021
    On Thu, 23 Dec 2021 21:53:27 +0000, Chris Schram wrote:

    I have grown more and more hard of hearing as I grow older. and I cannot always hear when someone is at the front door. I'm looking for a motion sensor that I can locate inside the front window.

    I have played briefly with an old Radio Shack infrared motion alarm that otherwise works fine, but can't "see" through glass at all.

    I also have a little Wyze security camera that can detect motion, but it seems way TOO sensitive to be useful.

    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

    I have purchased (through AliExpress) a number of RCWL0516 "Doppler Microwave" motion sensors that provide (among other things) a single-bit binary interface suitable for use with one of the Raspberry PI's digital pins.

    As the device uses weak microwave radiation, it can sense motion through glass, brick or drywall, and has an adjustable range of up to 5 metres (about 15 feet) depending on the intervening media.

    These devices typically cost less that $1.00 (excluding shipping).

    Perhaps one of these would work for you.
    --
    Lew Pitcher
    "In Skills, We Trust"
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  • From David Higton@3:770/3 to Axel Berger on Thu Dec 23 22:25:06 2021
    In message <61C4F25D.BFE103A3@Berger-Odenthal.De>
    Axel Berger <Spam@Berger-Odenthal.De> wrote:

    Chris Schram wrote:
    It would be used in some sort of RasPi or Arduino configuration.

    That might work, but it's a lot of hassle and complication. The doorbell already is an electric signal. Could you not use that directly?

    I did that. I bought a wireless doorbell with two "ringers"; one is in
    the hall in conventional use, the other is hooked up to an old BeagleBoard
    that had become spare. I found that the electronics could be powered
    from 5 volts, available from the BB, so it didn't need plugging in to
    the mains - fortunate, as the power supply is a non-isolated type.

    I wrote some software to send a message to Pushover, which sends me an
    alert on my mobile phone. It usually arrives within 2 seconds, but it
    has to be admitted that occasionally it takes much longer, so it's
    definitely not ideal.

    The same idea can be used with a conventional doorbell. It's just a
    case of appropriate interfacing.

    As for why: in our house, if we're in the sun lounge, the ringer in
    the hall is completely inaudible. Same applies if we're in the garden.
    There are other places where we can be, and the sound of what we're
    doing can drown the doorbell. So it's a different use case, but it
    boils down to the same thing.

    If anyone knows a way to get notifications to a mobile phone that are
    always timely, I'd like to know.

    David
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  • From Chris Schram@3:770/3 to Lew Pitcher on Thu Dec 23 23:48:00 2021
    On 2021-12-23, Lew Pitcher <lew.pitcher@digitalfreehold.ca> wrote:
    On Thu, 23 Dec 2021 21:53:27 +0000, Chris Schram wrote:

    I have grown more and more hard of hearing as I grow older. and I cannot
    always hear when someone is at the front door. I'm looking for a motion
    sensor that I can locate inside the front window.

    I have played briefly with an old Radio Shack infrared motion alarm that
    otherwise works fine, but can't "see" through glass at all.

    I also have a little Wyze security camera that can detect motion, but it
    seems way TOO sensitive to be useful.

    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

    I have purchased (through AliExpress) a number of RCWL0516 "Doppler Microwave" motion sensors that provide (among other things) a
    single-bit binary interface suitable for use with one of the Raspberry
    PI's digital pins.

    As the device uses weak microwave radiation, it can sense motion
    through glass, brick or drywall, and has an adjustable range of up to
    5 metres (about 15 feet) depending on the intervening media.

    These devices typically cost less that $1.00 (excluding shipping).

    Perhaps one of these would work for you.

    I'll explore that option then. Might be an amusing winter project. It
    also occurs to me that there may be some Arduino peripherals that can
    output some relatively loud noise. I may be able to forego the Pi
    altogether. Thanks for the quick response.

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  • From Chris Schram@3:770/3 to Axel Berger on Thu Dec 23 23:40:57 2021
    On 2021-12-23, Axel Berger <Spam@Berger-Odenthal.De> wrote:
    Chris Schram wrote:
    It would be used in some sort of RasPi or Arduino configuration.

    That might work, but it's a lot of hassle and complication. The doorbell already is an electric signal. Could you not use that directly?

    Heh! You don't know about my doorbell. It's a brass replica of an
    antique. You twist a knob on the outside of the door which spins a
    clapper against the bell on the inside. No electronics, or even
    electricity involved.

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  • From Axel Berger@3:770/3 to Chris Schram on Fri Dec 24 03:03:54 2021
    Chris Schram wrote:
    Heh! You don't know about my doorbell.

    Correct. In that case I modify my suggestion and suggest that a
    microphone with some very simple electronics right next to the clanger
    is simpler and more relible than anything optical.


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  • From GlowingBlueMist@3:770/3 to Chris Schram on Thu Dec 23 23:38:45 2021
    On 12/23/2021 3:53 PM, Chris Schram wrote:
    I have grown more and more hard of hearing as I grow older. and I cannot always hear when someone is at the front door. I'm looking for a motion sensor that I can locate inside the front window.

    I have played briefly with an old Radio Shack infrared motion alarm that otherwise works fine, but can't "see" through glass at all.

    I also have a little Wyze security camera that can detect motion, but it seems way TOO sensitive to be useful.

    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

    You might want to look into the doorbell units sold at this link. https://www.amazon.com/Wireless-Doorbell-1PlusOne-Waterproof-Transmitter/dp/B07C24N61X/ref=psdc_6291370011_t2_B08XYKY9R2

    The claim you can purchase more receivers or units and using push-button settings you can connect them all together and have the doorbell ring in
    say 8 rooms or how ever many you combine together.

    No, I have not used the product myself.
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  • From Andy Burns@3:770/3 to Chris Schram on Fri Dec 24 07:33:55 2021
    Chris Schram wrote:

    I cannot
    always hear when someone is at the front door. I'm looking for a motion sensor that I can locate inside the front window.
    Look at Andreas "guy with the swiss accent" Spiess on youtube, he has videos on various sensor types, including radar type, and connecting to rPi and microcontrollers.

    e.g. this playlist, but search his channel for more ...

    <https://www.youtube.com/playlist?list=PL3XBzmAj53RmryaFf7vyAP6U3f7H_5Lfk>
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  • From The Natural Philosopher@3:770/3 to Chris Schram on Fri Dec 24 08:39:55 2021
    On 23/12/2021 21:53, Chris Schram wrote:
    I have grown more and more hard of hearing as I grow older. and I cannot always hear when someone is at the front door. I'm looking for a motion sensor that I can locate inside the front window.

    I have played briefly with an old Radio Shack infrared motion alarm that otherwise works fine, but can't "see" through glass at all.

    I also have a little Wyze security camera that can detect motion, but it seems way TOO sensitive to be useful.

    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

    I would be inclined to think in terms of burglar alarm sensors.


    --
    “But what a weak barrier is truth when it stands in the way of an hypothesis!â€

    Mary Wollstonecraft
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  • From Chris Green@3:770/3 to Lew Pitcher on Fri Dec 24 08:57:17 2021
    Lew Pitcher <lew.pitcher@digitalfreehold.ca> wrote:
    On Thu, 23 Dec 2021 21:53:27 +0000, Chris Schram wrote:

    I have grown more and more hard of hearing as I grow older. and I cannot always hear when someone is at the front door. I'm looking for a motion sensor that I can locate inside the front window.

    I have played briefly with an old Radio Shack infrared motion alarm that otherwise works fine, but can't "see" through glass at all.

    I also have a little Wyze security camera that can detect motion, but it seems way TOO sensitive to be useful.

    Could ultrasonic be the way to go? That's a technology I've yet to play with. It would be used in some sort of RasPi or Arduino configuration.

    I have purchased (through AliExpress) a number of RCWL0516 "Doppler Microwave"
    motion sensors that provide (among other things) a single-bit binary interface
    suitable for use with one of the Raspberry PI's digital pins.

    As the device uses weak microwave radiation, it can sense motion through glass,
    brick or drywall, and has an adjustable range of up to 5 metres (about 15 feet)
    depending on the intervening media.

    These devices typically cost less that $1.00 (excluding shipping).

    Yes, I was going to say that microwave as opposed to infrared (PIR)
    motion sensors work through doors, windows, etc.

    Over here (UK) the DIY sheds have both PIR and microwave sensors available quite cheaply.

    --
    Chris Green
    ·
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  • From A. Dumas@3:770/3 to Axel Berger on Fri Dec 24 09:40:33 2021
    Axel Berger <Spam@Berger-Odenthal.De> wrote:
    Chris Schram wrote:
    Heh! You don't know about my doorbell.

    Correct. In that case I modify my suggestion and suggest that a
    microphone with some very simple electronics right next to the clanger
    is simpler and more relible than anything optical.

    Easy to set up initially but might be very hard (fft) if it has to
    distinguish the bell from other sounds, if those are about the same level.
    So I'd be inclined to fit a microswitch to the bell mechanism. Easy, direct on/off signal but probably a little more finicky to set up.
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  • From Axel Berger@3:770/3 to A. Dumas on Fri Dec 24 12:38:37 2021
    "A. Dumas" wrote:
    Easy to set up initially but might be very hard (fft) if it has to distinguish the bell from other sounds, if those are about the same level.
    So I'd be inclined to fit a microswitch to the bell mechanism. Easy, direct on/off signal but probably a little more finicky to set up.

    I disagree about the reliability. Sound decays with the square root law.
    If you place a microphone right nexr to the source it will be hard to
    confuse it with an external equally strong signal anf if that happens it
    should be obvious.

    You can get a mechanical switch to be reliable for a long tinme, but
    it's hard.

    The suggested optical (or microwave) slution will be the least reliable
    of all, I expect.


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  • From Chris Elvidge@3:770/3 to Chris Schram on Fri Dec 24 13:01:54 2021
    On 23/12/2021 21:53, Chris Schram wrote:
    I have grown more and more hard of hearing as I grow older. and I cannot always hear when someone is at the front door. I'm looking for a motion sensor that I can locate inside the front window.

    I have played briefly with an old Radio Shack infrared motion alarm that otherwise works fine, but can't "see" through glass at all.

    I also have a little Wyze security camera that can detect motion, but it seems way TOO sensitive to be useful.

    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.


    Assuming you already have a "push" doorbell on the outside, can you not
    attach a lightbulb in parallel with the inside ringer?
    Alternatively https://www.amazon.co.uk/gp/product/B01LQBRKXG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
    It has a blue flashing light on the receiver.


    --
    Chris Elvidge
    England
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  • From Folderol@3:770/3 to Chris Schram on Fri Dec 24 15:05:43 2021
    On Thu, 23 Dec 2021 21:53:27 -0000 (UTC)
    Chris Schram <chrispam1@me.com> wrote:

    I have grown more and more hard of hearing as I grow older. and I cannot >always hear when someone is at the front door. I'm looking for a motion >sensor that I can locate inside the front window.

    I have played briefly with an old Radio Shack infrared motion alarm that >otherwise works fine, but can't "see" through glass at all.

    I also have a little Wyze security camera that can detect motion, but it >seems way TOO sensitive to be useful.

    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

    Use a short range proximity photocell pointing at the clapper mechanism,
    then an arduino to monitor *change* of state, so it doesn't matter if the mech stops with the photocell obscured or not.
    Something like this:

    https://www.amazon.co.uk/Photocell-Infrared-Photoelectric-Proximity-Outside/dp/B093HGNWT1/ref=sr_1_11?_encoding=UTF8&c=ts&keywords=Photoelectric+Sensors&qid=1640358044&s=industrial&sr=1-11&ts_id=10256556031


    Use two of the arduino outputs in antiphase at (say) 2kHz to directly drive a ceramic sounder.

    Done this sort of thing loads of times :)

    --
    Basic
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  • From Dennis Lee Bieber@3:770/3 to All on Fri Dec 24 11:32:40 2021
    On Thu, 23 Dec 2021 21:53:27 -0000 (UTC), Chris Schram <chrispam1@me.com> declaimed the following:


    I have played briefly with an old Radio Shack infrared motion alarm that >otherwise works fine, but can't "see" through glass at all.

    Not really surprising -- it's one reason car and home interiors get warm when the sun shines on glass. Ultraviolet light passes through glass,
    gets absorbed by fabrics and what-have-you on the inside, and those items
    then re-radiate the energy in the infrared band.


    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

    Sorry -- ultrasonic sensors will reflect off the window itself. You'll pretty much have to fit the sensor (for almost anything except image
    processing type detection [this image differs from last image]) outside the window and run leads to the R-Pi (or whatever you use to process data).

    A PIR sensor /might/ be usable in daylight (they are commonly used for auto-activation motion detect security lights). They trigger on an IR
    source moving between segments in the sensor window. https://learn.adafruit.com/pir-passive-infrared-proximity-motion-sensor/how-pirs-work

    Ultrasonic ("PING)))" -- yes, the ))) is part of the name for some) sensors are more distance detection items than motion sensors, and may not
    have a great range. Some old Polaroid cameras used them for focusing -- but
    one has to account for the default focus being "infinity", and
    depth-of-field on those being deep enough that anything around 15+ feet was considered "infinity".

    https://www.parallax.com/product/ping-ultrasonic-distance-sensor/ (10ft
    range)
    https://learn.adafruit.com/ultrasonic-sonar-distance-sensors (suggests
    13ft, but recommends 8ft)


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  • From Computer Nerd Kev@3:770/3 to druck on Fri Dec 24 21:48:14 2021
    druck <news@druck.org.uk> wrote:
    On 23/12/2021 21:53, Chris Schram wrote:
    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

    Ultrasonic wont see through glass or the clear lid of an electronic box,
    (I did check to be sure). So it would need to be mounted externally, and
    then you have the problem of weather proofing.

    There are waterproof ones available, I bought one to use as a tank
    water level sensor and the sensor is completely sealed up. Then again
    the same applies to IR solutions, so one has to assume the OP just
    doesn't like electronics outside.

    I didn't see anyone mention mounting a laser pointing at a
    slightly-angled mirror outside which reflects the beam back to a
    light sensor. Just one more option, so long as it can be mounted
    at a height where people won't accidentally look into it.

    --
    __ __
    #_ < |\| |< _#
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  • From Chris Elvidge@3:770/3 to Dennis Lee Bieber on Fri Dec 24 22:19:45 2021
    On 24/12/2021 16:32, Dennis Lee Bieber wrote:
    On Thu, 23 Dec 2021 21:53:27 -0000 (UTC), Chris Schram <chrispam1@me.com> declaimed the following:


    I have played briefly with an old Radio Shack infrared motion alarm that
    otherwise works fine, but can't "see" through glass at all.

    Not really surprising -- it's one reason car and home interiors get warm when the sun shines on glass. Ultraviolet light passes through glass, gets absorbed by fabrics and what-have-you on the inside, and those items then re-radiate the energy in the infrared band.


    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

    Sorry -- ultrasonic sensors will reflect off the window itself. You'll pretty much have to fit the sensor (for almost anything except image processing type detection [this image differs from last image]) outside the window and run leads to the R-Pi (or whatever you use to process data).

    A PIR sensor /might/ be usable in daylight (they are commonly used for auto-activation motion detect security lights). They trigger on an IR
    source moving between segments in the sensor window. https://learn.adafruit.com/pir-passive-infrared-proximity-motion-sensor/how-pirs-work

    Ultrasonic ("PING)))" -- yes, the ))) is part of the name for some) sensors are more distance detection items than motion sensors, and may not have a great range. Some old Polaroid cameras used them for focusing -- but one has to account for the default focus being "infinity", and
    depth-of-field on those being deep enough that anything around 15+ feet was considered "infinity".

    https://www.parallax.com/product/ping-ultrasonic-distance-sensor/ (10ft range)
    https://learn.adafruit.com/ultrasonic-sonar-distance-sensors (suggests
    13ft, but recommends 8ft)



    I've got a Raspberry Pi B with a Pi Camera mounted and use the 'motion'
    package to record video when motion is detected - through a window.
    Video is not very high quality, but you don't need that.
    You could use inotify to watch the destination directory and email you
    when motion is recorded.


    --
    Chris Elvidge
    England
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From druck@3:770/3 to Chris Schram on Fri Dec 24 21:28:10 2021
    On 23/12/2021 21:53, Chris Schram wrote:
    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

    Ultrasonic wont see through glass or the clear lid of an electronic box,
    (I did check to be sure). So it would need to be mounted externally, and
    then you have the problem of weather proofing.

    ---druck
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Chris Elvidge@3:770/3 to Chris Elvidge on Sat Dec 25 00:16:26 2021
    On 24/12/2021 22:19, Chris Elvidge wrote:
    On 24/12/2021 16:32, Dennis Lee Bieber wrote:
    On Thu, 23 Dec 2021 21:53:27 -0000 (UTC), Chris Schram <chrispam1@me.com>
    declaimed the following:


    I have played briefly with an old Radio Shack infrared motion alarm that >>> otherwise works fine, but can't "see" through glass at all.

    Not really surprising -- it's one reason car and home interiors get
    warm when the sun shines on glass. Ultraviolet light passes through
    glass,
    gets absorbed by fabrics and what-have-you on the inside, and those items
    then re-radiate the energy in the infrared band.


    Could ultrasonic be the way to go? That's a technology I've yet to play
    with. It would be used in some sort of RasPi or Arduino configuration.

    Sorry -- ultrasonic sensors will reflect off the window itself.
    You'll
    pretty much have to fit the sensor (for almost anything except image
    processing type detection [this image differs from last image])
    outside the
    window and run leads to the R-Pi (or whatever you use to process data).

    A PIR sensor /might/ be usable in daylight (they are commonly used
    for
    auto-activation motion detect security lights). They trigger on an IR
    source moving between segments in the sensor window.
    https://learn.adafruit.com/pir-passive-infrared-proximity-motion-sensor/how-pirs-work


    Ultrasonic ("PING)))" -- yes, the ))) is part of the name for some)
    sensors are more distance detection items than motion sensors, and may
    not
    have a great range. Some old Polaroid cameras used them for focusing
    -- but
    one has to account for the default focus being "infinity", and
    depth-of-field on those being deep enough that anything around 15+
    feet was
    considered "infinity".

    https://www.parallax.com/product/ping-ultrasonic-distance-sensor/ (10ft
    range)
    https://learn.adafruit.com/ultrasonic-sonar-distance-sensors (suggests
    13ft, but recommends 8ft)



    I've got a Raspberry Pi B with a Pi Camera mounted and use the 'motion' package to record video when motion is detected - through a window.
    Video is not very high quality, but you don't need that.
    You could use inotify to watch the destination directory and email you
    when motion is recorded.



    I've just tried it - yes it does work.
    The only problem is the email delay if your email program doesn't pick
    up quickly.

    Run this file from /etc/cron.d/inotify
    @reboot root /root/bin/inotify

    #!/bin/bash
    #/root/bin/inotify
    sleep 10
    inotifywait --quiet --recursive --monitor --event create \
    --timefmt "%A %Y-%m-%d %H:%M" --format "%T %e %w %f" \
    /home/pi/pics | \
    while read change; do
    mail -s "Motion video event" osmc@osmc-3plus.local <<<"$change"
    done


    --
    Chris Elvidge
    England
    --- SoupGate-Win32 v1.05
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  • From David Higton@3:770/3 to Chris Schram on Sat Dec 25 20:07:33 2021
    In message <sq31e8$1dhv$1@gioia.aioe.org>
    Chris Schram <chrispam1@me.com> wrote:

    On 2021-12-23, Axel Berger <Spam@Berger-Odenthal.De> wrote:
    Chris Schram wrote:
    It would be used in some sort of RasPi or Arduino configuration.

    That might work, but it's a lot of hassle and complication. The doorbell already is an electric signal. Could you not use that directly?

    Heh! You don't know about my doorbell. It's a brass replica of an antique. You twist a knob on the outside of the door which spins a clapper against
    the bell on the inside. No electronics, or even electricity involved.

    OK, here's a suggestion for sensing the bell (which, I recognise, isn't
    what you asked for, but might be a good alternative).

    Sense the movement of the clapper by optical reflection.

    Either paint a white spot on it, or attach reflective tape, somewhere
    that a reflective sensor can see. You may find that you need two sensors
    so as to avoid the problem where the clapper comes to rest just on the threshold of one sensor, and, despite hysteresis, you might find it's
    changing state frequently and causing false triggers; if so, position a
    second sensor such that it can't possibly be on the threshold at the
    same time, and look for changes (in either direction) from both sensors.

    I'm still looking forward to hearing what you propose as the method to
    alert you, whatever the detector is.

    David
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