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TWS/RWS 434 RF Question — Parallax Forums

TWS/RWS 434 RF Question

ArchiverArchiver Posts: 46,084
edited 2000-10-24 07:54 in General Discussion
I'm building a wireless model rocket launcher and I am using a TWS/RWS 434
TX/RX in both the remote and the base unit. Both rx/tx pairs work fine on
their own, but when I try to transmit with both transmitters at the same
time the signal gets cancelled out or something and neither of the receivers
picks up a signal. Any help on a solution to this problem would be greatly
appreciated.

Mike

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Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-10-23 19:10
    I've not used these but I'd expect that the unit's can not receive while
    transmitting.

    Don't over look safety issues here!!!
    You'd hate to have a rocket launched up your nose due to the neighbor kid
    playing with his walkie-talkie!!...


    Original Message
    From: Michael Narwold [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=c9Oild9W6EUYM3hWpqS9NIm3LM677PzNtxu_MpXNYyk4nonUZ1lYrXonfLIi5O679fcyJW_ZPedw9g]mnarwold@h...[/url
    Sent: Monday, October 23, 2000 10:10 AM
    To: basicstamps@egroups.com
    Subject: [noparse][[/noparse]basicstamps] TWS/RWS 434 RF Question


    I'm building a wireless model rocket launcher and I am using a TWS/RWS 434
    TX/RX in both the remote and the base unit. Both rx/tx pairs work fine on
    their own, but when I try to transmit with both transmitters at the same
    time the signal gets cancelled out or something and neither of the receivers

    picks up a signal. Any help on a solution to this problem would be greatly
    appreciated.

    Mike

    _________________________________________________________________________
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  • ArchiverArchiver Posts: 46,084
    edited 2000-10-23 20:07
    Mike,

    Why not use a single transmitter with an encoder/decoder setup for controlling
    both receivers..? This should take care of the problem you're having with the
    operation of two separate transmitter/receivers in close proximity.

    As Michael Witherspoon mentioned earlier, it would help eliminate to possibility
    of the rocket up the nose occurrence as well by forcing each receiver to respond
    only when an address match is received.

    A single transmitter using an encoder/decoder scheme can control quite a few
    receivers.

    Regards,

    Bruce
    webmaster@r...
    http://www.rentron.com


    Original Message
    From: "Michael Narwold" <mnarwold@h...>
    To: <basicstamps@egroups.com>
    Sent: Monday, October 23, 2000 11:10 AM
    Subject: [noparse][[/noparse]basicstamps] TWS/RWS 434 RF Question


    | I'm building a wireless model rocket launcher and I am using a TWS/RWS 434
    | TX/RX in both the remote and the base unit. Both rx/tx pairs work fine on
    | their own, but when I try to transmit with both transmitters at the same
    | time the signal gets cancelled out or something and neither of the receivers
    | picks up a signal. Any help on a solution to this problem would be greatly
    | appreciated.
    |
    | Mike
    |
    | _________________________________________________________________________
    | Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
    |
    | Share information about yourself, create your own public profile at
    | http://profiles.msn.com.
    |
    |
    |
    |
    |
  • ArchiverArchiver Posts: 46,084
    edited 2000-10-23 23:54
    The reason I need two TX is taht I am sending a signal from the base that
    tells me whether the ignitor has a good connection and also after the launch
    to see in the ignitor fired. I am using two different addresses for each
    TX/RX pair, but it's not working how I expected it.


    >From: "Bruce" <breyno2@r...>
    >Reply-To: basicstamps@egroups.com
    >To: <basicstamps@egroups.com>
    >Subject: Re: [noparse][[/noparse]basicstamps] TWS/RWS 434 RF Question
    >Date: Mon, 23 Oct 2000 13:07:21 -0600
    >
    >Mike,
    >
    >Why not use a single transmitter with an encoder/decoder setup for
    >controlling
    >both receivers..? This should take care of the problem you're having with
    >the
    >operation of two separate transmitter/receivers in close proximity.
    >
    >As Michael Witherspoon mentioned earlier, it would help eliminate to
    >possibility
    >of the rocket up the nose occurrence as well by forcing each receiver to
    >respond
    >only when an address match is received.
    >
    >A single transmitter using an encoder/decoder scheme can control quite a
    >few
    >receivers.
    >
    >Regards,
    >
    >Bruce
    >webmaster@r...
    >http://www.rentron.com
    >
    >
    >
    Original Message
    >From: "Michael Narwold" <mnarwold@h...>
    >To: <basicstamps@egroups.com>
    >Sent: Monday, October 23, 2000 11:10 AM
    >Subject: [noparse][[/noparse]basicstamps] TWS/RWS 434 RF Question
    >
    >
    >| I'm building a wireless model rocket launcher and I am using a TWS/RWS
    >434
    >| TX/RX in both the remote and the base unit. Both rx/tx pairs work fine
    >on
    >| their own, but when I try to transmit with both transmitters at the same
    >| time the signal gets cancelled out or something and neither of the
    >receivers
    >| picks up a signal. Any help on a solution to this problem would be
    >greatly
    >| appreciated.
    >|
    >| Mike
    >|
    >| _________________________________________________________________________
    >| Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
    >|
    >| Share information about yourself, create your own public profile at
    >| http://profiles.msn.com.
    >|
    >|
    >|
    >|
    >|
    >
    >
    >
    >

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  • ArchiverArchiver Posts: 46,084
    edited 2000-10-24 00:13
    Mike,

    Using two transmitters in close proximity at the same frequency
    will cause interference. If you have only one transmitter operational
    at any given time, it can work. Operating both at the same time
    will not. This would require totally separate channels like you see
    with hobby airplane type RF remote control systems.

    If you can figure out a way to synchronize the two separate transmitters
    and have only "one" transmitting at a time, it will work. Even a short
    delay should get you in the ball-park.

    Bruce
    webmaster@r...
    http://www.rentron.com


    Original Message
    From: "Michael Narwold" <mnarwold@h...>
    To: <basicstamps@egroups.com>
    Sent: Monday, October 23, 2000 4:54 PM
    Subject: Re: [noparse][[/noparse]basicstamps] TWS/RWS 434 RF Question


    | The reason I need two TX is taht I am sending a signal from the base that
    | tells me whether the ignitor has a good connection and also after the launch
    | to see in the ignitor fired. I am using two different addresses for each
    | TX/RX pair, but it's not working how I expected it.
  • ArchiverArchiver Posts: 46,084
    edited 2000-10-24 07:08
    perhaps - assuming you have the rocket in visual range -
    you'd do better to have strobed LEDs [noparse][[/noparse]or zenon bike lite]
    to show the ignitor connection and post condition. Visually.

    I don't like the idea of having a transmitter working next
    to the firing receiver whatever the coding may be... too much
    room for error [noparse][[/noparse]I almost lost my life in a pyrotechnic
    accident 50 years ago so I know something about this :-) ].

    <><><>
    Date: Mon, 23 Oct 2000 17:54:19 EST
    From: "Michael Narwold" <mnarwold@h...>

    The reason I need two TX is that I am sending a signal from the base that

    tells me whether the ignitor has a good connection and also after the
    launch
    to see in the ignitor fired. I am using two different addresses for each

    TX/RX pair, but it's not working how I expected it.

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  • ArchiverArchiver Posts: 46,084
    edited 2000-10-24 07:54
    OK an other possible way to do this safely is to turn
    the launch pad transmitter on intermittently for a
    short time and DISABLE the launch pad _receiver_ just
    before till just after the transmitter has sent its
    information. Say .1 second before till .1 second
    after a .5 second transmitter pulse every two seconds.
    [noparse][[/noparse]assuming the decoders and filters work this fast].

    Then your pad receiver is active more than half the time
    with less than a second delay... anyhow this sort of
    reasoning can lead to somewhere workable and safe...

    I'd still prefer no transmitters near the firing receiver.

    <><><>
    Date: Mon, 23 Oct 2000 17:54:19 EST
    From: "Michael Narwold" <mnarwold@h...>

    The reason I need two TX is that I am sending a signal from the base that

    tells me whether the ignitor has a good connection and also after the
    launch
    to see in the ignitor fired. I am using two different addresses for each

    TX/RX pair, but it's not working how I expected it.
    End forwarded message

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    YOU'RE PAYING TOO MUCH FOR THE INTERNET!
    Juno now offers FREE Internet Access!
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