• how to connect more sensors

    From mario_rossi@peppercom.it@3:770/3 to All on Tue May 28 16:11:56 2019
    Hi everybody, sorry for being newbie, at the moment I'm doing an exercise for the school, a meteo station with 4 sensors. I installed raspbian and use it with Putty and VLC. The question is how I connect, at SLK and SDA pins the 3 sensors school gave me (
    the fourth -VOC- is serial, has its own connection). I'm not a technician and have a little manual skill, so I ignore the way to do it. The aim is to connect
    simultaneously the 3 sensors, by now I can only use one sensor only. What hardware is the
    solution? Thankyou
    Marius

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  • From R.Wieser@3:770/3 to All on Wed May 29 02:16:30 2019
    Mario,

    The question is how I connect, at SLK and SDA pins the 3
    sensors school gave

    You didn't specify it, but I'm assuming you're talking about I2C (its SCLK
    by the way) than how are you currently talking to your first device ?
    Isn't there a "device address" involved ? And if so, do the two other
    devices not have their own addresses ?

    In that case its rather easy: You connect all three devices to the RPi's
    SCLK and SDA pins, and talk to each of them by their device adresses. Each device on that bus listens if their address is send, and irf not ignores the following databytes.

    ... which is a thing that they should have explained in class. <whistle>

    Also, you could also google "I2C protocol" and get a much better
    explanation, and most likely some example code too.

    Regards,
    Rudy Wieser

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  • From Martin Gregorie@3:770/3 to All on Tue May 28 23:57:26 2019
    On Tue, 28 May 2019 12:11:56 -0700, mario_rossi wrote:

    Hi everybody, sorry for being newbie, at the moment I'm doing an
    exercise for the school, a meteo station with 4 sensors. I installed
    raspbian and use it with Putty and VLC. The question is how I connect,
    at SLK and SDA pins the 3 sensors school gave me (the fourth -VOC- is
    serial, has its own connection). I'm not a technician and have a little manual skill, so I ignore the way to do it. The aim is to connect simultaneously the 3 sensors, by now I can only use one sensor only.
    What hardware is the solution? Thankyou Marius

    Nobody here can help unless we know exactly what the four sensors are,
    who made them, and what model they are.

    Its unreasonable to say "I can't solder connections and can't be bothered
    to read the instructions" and expect us to do your job for free.

    So, at a minimum you need to tell us exactly what each sensor measures as
    well as its make and model. You also need to provide working URLs for the online documentation for each sensor.

    To be useful this documentation needs to describe the hardware (datasheet wiring diagrams, etc) in enough detail for a competent person to
    understand how to connect it to an RPi and its configured. It should also include documentation for any supporting software if this is supplied
    with the sensor.


    --
    Martin | martin at
    Gregorie | gregorie dot org

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  • From Jim H@3:770/3 to martin@mydomain.invalid on Wed May 29 00:25:58 2019
    On Tue, 28 May 2019 19:57:26 +0000 (UTC), in
    <qck3r6$jai$1@news.albasani.net>, Martin Gregorie
    <martin@mydomain.invalid> wrote:

    On Tue, 28 May 2019 12:11:56 -0700, mario_rossi wrote:

    Hi everybody, sorry for being newbie, at the moment I'm doing an
    exercise for the school, a meteo station with 4 sensors. I installed
    raspbian and use it with Putty and VLC. The question is how I connect,
    at SLK and SDA pins the 3 sensors school gave me (the fourth -VOC- is
    serial, has its own connection). I'm not a technician and have a little
    manual skill, so I ignore the way to do it. The aim is to connect
    simultaneously the 3 sensors, by now I can only use one sensor only.
    What hardware is the solution? Thankyou Marius

    Nobody here can help unless we know exactly what the four sensors are,
    who made them, and what model they are.

    Its unreasonable to say "I can't solder connections and can't be bothered
    to read the instructions" and expect us to do your job for free.

    So, at a minimum you need to tell us exactly what each sensor measures as >well as its make and model. You also need to provide working URLs for the >online documentation for each sensor.

    To be useful this documentation needs to describe the hardware (datasheet >wiring diagrams, etc) in enough detail for a competent person to
    understand how to connect it to an RPi and its configured. It should also >include documentation for any supporting software if this is supplied
    with the sensor.

    After which, shouldn't the student also show what he's done so far -
    code and connections - to do his own homework?

    --
    Jim H

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  • From mark lewis@1:3634/12.73 to Martin Gregorie on Tue May 28 23:07:12 2019
    On 2019 May 28 19:57:26, you wrote to All:

    Its unreasonable to say "I can't solder connections and can't be bothered to read the instructions" and expect us to do your job for free.

    job? more like school work...

    -- rumplestiltskin

    )\/(ark

    Always Mount a Scratch Monkey
    Do you manage your own servers? If you are not running an IDS/IPS yer doin' it wrong...
    ... Never read the fine print. You're not going to like it.
    ---
    * Origin: (1:3634/12.73)
  • From Dennis Lee Bieber@3:770/3 to All on Tue May 28 22:33:10 2019
    On Tue, 28 May 2019 12:11:56 -0700 (PDT), mario_rossi@peppercom.it
    declaimed the following:

    Hi everybody, sorry for being newbie, at the moment I'm doing an exercise for the school, a meteo station with 4 sensors. I installed raspbian and use it with Putty and VLC. The question is how I connect, at SLK and SDA pins the 3

    "SLK" I don't recognize.

    Are they I2C or SPI. If I2C you just hook them (SCL and SDA) in parallel -- as each device should have its own address, which gets sent in
    the data stream to identify which device is being commanded.

    SCL -----------------------------------------------------------
    | | | |
    rpi sen1 sen2 sen3
    | | | |
    SDA -----------------------------------------------------


    For SPI, you will need to allocate one GPIO per device to act as a chip-select (depending on wiring either set these with pull-up resistors
    and drive one GPIO low to select a sensor, or pull-down resistors and drive
    one GPIO high to select the sensor). With the sensor selection, send the appropriate commands and read the return data (SPI tends to send a return
    bit for every bit sent to a device). SPI uses two data lines MOSI/MISO and
    a clock -- shared by all devices, and separate select lines.



    --
    Wulfraed Dennis Lee Bieber AF6VN
    wlfraed@ix.netcom.com http://wlfraed.microdiversity.freeddns.org/

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  • From mario_rossi@peppercom.it@3:770/3 to All on Tue May 28 21:05:15 2019
    ...I'm not very good in using newsgroup functions :-( anyway, I copy here the urls of each sensor and other devices professor said we'll use,

    1) https://learn.adafruit.com/pm25-air-quality-sensor/overview (PM1.0, PM2.5
    and PM10 measurer)
    2) https://www.adafruit.com/product/3251 (temp+umidity)
    3) https://www.adafruit.com/product/3709 (serial VOC and CO2)
    4) https://www.adafruit.com/product/2651 (pressure+altitude)
    5) https://uk.rs-online.com/web/p/processor-microcontroller-development-kits/1373331/?relevancy-data=636F3D3126696E3D

    https://www.robotstore.it/Set-di-Cavetti-40-Poli-F-F-30cm-comp-Arduino

    I didn't say but, we (group of students) soldered all the "holes" (sda, scl...)
    with a comb-like metal (like this ++++), so that the pins one side coming from sensor enter the cablet whose other side connects to right pin on Rpi. This is our problem (I
    think it is the thinnest of all the problems :-) but we're still beginners), a cablet is for 1 sensor but the pins on Rpi are only 2... What is needed is a "multicablet": 1 end to the Rpi,
    that divides in more ends at the other side, so the sensors can share the communication with the processor

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  • From Jean-Pierre Kuypers@3:770/3 to Gregorie on Wed May 29 14:33:20 2019
    In article (Dans l'article) <qck3r6$jai$1@news.albasani.net>, Martin
    Gregorie <martin@mydomain.invalid> wrote (écrivait) :

    Its unreasonable to say "I can't solder connections and can't be bothered
    to read the instructions" and expect us to do your job for free.

    It may not be unreasonable to think that an expert would be able to
    give a friendly advice to a young student and to give him some ideas to
    move towards the solution ... for free.

    --

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  • From Martin Gregorie@3:770/3 to mark lewis on Wed May 29 16:38:10 2019
    On Tue, 28 May 2019 19:07:12 +1300, mark lewis wrote:

    On 2019 May 28 19:57:26, you wrote to All:

    Its unreasonable to say "I can't solder connections and can't be
    bothered MG> to read the instructions" and expect us to do your job for
    free.

    job? more like school work...

    Yes, that's possible. I said 'job' because I thought the OP might be a
    friend of a staff member who was thought to understand RPIs and so been 'volunteered' to help before finding himself out of his depth.


    --
    Martin | martin at
    Gregorie | gregorie dot org

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  • From Martin Gregorie@3:770/3 to Jean-Pierre Kuypers on Wed May 29 16:42:59 2019
    On Wed, 29 May 2019 10:33:20 +0200, Jean-Pierre Kuypers wrote:

    In article (Dans l'article) <qck3r6$jai$1@news.albasani.net>, Martin
    Gregorie <martin@mydomain.invalid> wrote (écrivait) :

    Its unreasonable to say "I can't solder connections and can't be
    bothered to read the instructions" and expect us to do your job for
    free.

    It may not be unreasonable to think that an expert would be able to give
    a friendly advice to a young student and to give him some ideas to move towards the solution ... for free.

    Agreed, but "I'm not a technician and have a little manual skill, so I
    ignore the way to do it" sounds much more like "do it for me because I
    don't want to" than "please help me learn how to do it".


    --
    Martin | martin at
    Gregorie | gregorie dot org

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  • From mm0fmf@3:770/3 to Martin Gregorie on Wed May 29 22:02:54 2019
    On 29/05/2019 13:42, Martin Gregorie wrote:
    On Wed, 29 May 2019 10:33:20 +0200, Jean-Pierre Kuypers wrote:

    In article (Dans l'article) <qck3r6$jai$1@news.albasani.net>, Martin
    Gregorie <martin@mydomain.invalid> wrote (écrivait) :

    Its unreasonable to say "I can't solder connections and can't be
    bothered to read the instructions" and expect us to do your job for
    free.

    It may not be unreasonable to think that an expert would be able to give
    a friendly advice to a young student and to give him some ideas to move
    towards the solution ... for free.

    Agreed, but "I'm not a technician and have a little manual skill, so I
    ignore the way to do it" sounds much more like "do it for me because I
    don't want to" than "please help me learn how to do it".


    Sounds more like someone who doesn't have English as a first language to
    me and this not being able to express their request simply.

    What makes me smile is it's fairly obvious from the signal names these
    are I2C sensors and nobody has told him to read about I2C.

    Hint: Mario, once you have read about I2C you need to find out if the
    sensors have different I2C addresses. If they do then you can connect
    them in parallel and you are nearly done.

    There, a hint on how to proceed without doing the job for the guy. You
    can all do it if you try.

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  • From Dennis Lee Bieber@3:770/3 to All on Wed May 29 17:13:40 2019
    On Tue, 28 May 2019 17:05:15 -0700 (PDT), mario_rossi@peppercom.it
    declaimed the following:


    I didn't say but, we (group of students) soldered all the "holes" (sda, scl...) with a comb-like metal (like this ++++), so that the pins one side coming from sensor enter the cablet whose other side connects to right pin on Rpi. This is our problem (I
    think it is the thinnest of all the problems :-) but we're still beginners), a cablet is for 1 sensor but the pins on Rpi are only 2... What is needed is a "multicablet": 1 end to the Rpi,
    that divides in more ends at the other side, so the sensors can share the communication with the processor

    What type of RPi do you have that you had to solder to it? All of mine came with a set of pins for connecting jumper wires

    (depending on what type of ends you need)
    https://www.adafruit.com/product/1950
    https://www.adafruit.com/product/1954
    https://www.adafruit.com/product/1957

    and a breadboard (for solderless development and component reuse) https://www.adafruit.com/product/64
    https://www.adafruit.com/product/239
    https://www.adafruit.com/product/3314

    or proto-board (for soldering a more permanent project -- these have copper
    in the same arrangement as a breadboard, so when the project works you just move the components to the same position on the proto-board and solder
    them)

    And here is one meant for direct jumpering of an RPi https://www.adafruit.com/product/1135

    breakout and cable for use on breadboard
    https://www.adafruit.com/product/914
    https://www.adafruit.com/product/571
    https://www.adafruit.com/product/590


    --
    Wulfraed Dennis Lee Bieber AF6VN
    wlfraed@ix.netcom.com http://wlfraed.microdiversity.freeddns.org/

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  • From =?UTF-8?Q?Bj=c3=b6rn_Lundin?=@3:770/3 to Dennis Lee Bieber on Wed May 29 23:17:31 2019
    On 2019-05-29 19:13, Dennis Lee Bieber wrote:

    What type of RPi do you have that you had to solder to it? All of mine came with a set of pins for connecting jumper wires


    My rpi zeros came with no pins soldered to the GPIO ports.
    Had to solder myself on both of them

    --
    --
    Bj├╢rn

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  • From Alister@3:770/3 to Jean-Pierre Kuypers on Wed May 29 21:43:28 2019
    On Wed, 29 May 2019 10:33:20 +0200, Jean-Pierre Kuypers wrote:

    In article (Dans l'article) <qck3r6$jai$1@news.albasani.net>, Martin
    Gregorie <martin@mydomain.invalid> wrote (écrivait) :

    Its unreasonable to say "I can't solder connections and can't be
    bothered to read the instructions" and expect us to do your job for
    free.

    It may not be unreasonable to think that an expert would be able to give
    a friendly advice to a young student and to give him some ideas to move towards the solution ... for free.

    I am more than willing to match the effort of the student in trying to
    solve any problem unfortunately in this case the effort appears to be
    ZERO

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  • From A. Dumas@3:770/3 to none@invalid.com on Wed May 29 23:59:48 2019
    mm0fmf <none@invalid.com> wrote:
    What makes me smile is it's fairly obvious from the signal names these
    are I2C sensors and nobody has told him to read about I2C.

    Hint: Mario, once you have read about I2C you need to find out if the
    sensors have different I2C addresses. If they do then you can connect
    them in parallel and you are nearly done.

    And don't forget the pullup resistors on the 2 lines. Try 4k7 for starters
    or see, e.g.: https://electronics.stackexchange.com/questions/1849/is-there-a-correct-resistance-value-for-i2c-pull-up-resistors/1852#1852

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  • From Rob Morley@3:770/3 to none@invalid.com on Thu May 30 00:39:38 2019
    On Wed, 29 May 2019 18:02:54 +0100
    mm0fmf <none@invalid.com> wrote:

    Sounds more like someone who doesn't have English as a first language
    to me and this not being able to express their request simply.

    Indeed - I read "I ignore" as "I am ignorant" rather than "I can't be
    bothered to look".

    What makes me smile is it's fairly obvious from the signal names
    these are I2C sensors and nobody has told him to read about I2C.

    Hint: Mario, once you have read about I2C you need to find out if the
    sensors have different I2C addresses. If they do then you can connect
    them in parallel and you are nearly done.

    There, a hint on how to proceed without doing the job for the guy.
    You can all do it if you try.

    Well done. :-)

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  • From Computer Nerd Kev@3:770/3 to Dennis Lee Bieber on Thu May 30 10:46:02 2019
    Dennis Lee Bieber <wlfraed@ix.netcom.com> wrote:
    On Tue, 28 May 2019 17:05:15 -0700 (PDT), mario_rossi@peppercom.it
    declaimed the following:


    I didn't say but, we (group of students) soldered all the "holes"
    (sda, scl...) with a comb-like metal (like this ++++), so that
    the pins one side coming from sensor enter the cablet whose
    other side connects to right pin on Rpi. This is our problem
    (I think it is the thinnest of all the problems :-) but we're
    still beginners), a cablet is for 1 sensor but the pins on Rpi
    are only 2... What is needed is a "multicablet": 1 end to the Rpi,
    that divides in more ends at the other side, so the sensors can
    share the communication with the processor

    What type of RPi do you have that you had to solder to it? All of mine came with a set of pins for connecting jumper wires

    Pi Zeros don't (except the WH), not sure about the others.

    or proto-board (for soldering a more permanent project -- these have copper in the same arrangement as a breadboard, so when the project works you just move the components to the same position on the proto-board and solder
    them)

    And here is one meant for direct jumpering of an RPi https://www.adafruit.com/product/1135

    breakout and cable for use on breadboard
    https://www.adafruit.com/product/914

    Note that those don't suit later Pi models with a 40pin GPIO header.

    --
    __ __
    #_ < |\| |< _#

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