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    Re: Active low transmitter question

    Excellent, voltage divider it is then.




    Yes I do fit into that category (mildly at present), will look at at a backup with Zenner.
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    Re: Active low transmitter question

    I never thought of that, great idea, cheers Richard.

    What do you think the best way to drop the 12v from the sensor output to 3.3v into the pic, would the voltage divider be ok/work?
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    Re: Active low transmitter question

    Ok - Instead of a schematic (can't find all components in menu I need to make drawing), have decided to talk through each section of the project as there isn't really that much to it if that's ok?,...
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    Re: Active low transmitter question

    "what relay ? specs ?"

    Hi Richard - I haven't got around to choosing one as yet.

    I need a relay activated by the pic (3.3v) via a transistor/mosfet to switch an alarm sounder on (fairly loud...
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    Re: Active low transmitter question

    Thanks again peterdeco1 - If there's two parts to order from, I'm the guy who orders the wrong one (but not in this case thanks to you).
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    Re: Active low transmitter question

    Thanks for the reply peterdeco1 - So would that be the same wiring / resistor configuration as the 2N7000 (see link diagram) a straight swap in other words?
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    Re: Active low transmitter question

    As an aside. Has anyone used a 2N7000 Mosfet attached to a 3.3v pic output to drive a relay?

    The schematic (link below) is exactly what I want to do from a pic output pin rather than the Receiver...
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    Re: Active low transmitter question

    Hi Richard / Everyone

    OK - So I managed to get a call into the salesman today and he said:

    First off the video. The module in the video is a Bravo module, very similar to the Gamma module (the...
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    Re: Active low transmitter question

    Just to help me - Data sheet says:



    Ok - This is my understanding / misunderstanding of how these things work - Please tell me which of these statements is correct / incorrect so that I can...
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    Re: Active low transmitter question

    Ok, ignoring the video and the different device and back onto this one.


    How do I mimic a 'single momentary' button press to ground on Transmitter Input pin1 using a pic instead of a button? do...
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    Re: Active low transmitter question

    Sorry guys another question from me.

    The demo video shows a lady pressing a push button to ground on Tx Input pin1, which on the Rx latches an led on, so:

    How do I mimic a 'single' button press...
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    Re: Active low transmitter question

    Hi Ioannis - I came across this short instructional / demo video for anyone else who's interested in this topic, simple video but shows Tx/Rx in action. It's not the exact same model as the ones I've...
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    Re: Active low transmitter question

    Thanks for that Ioannis - I think 3.3v is the best option here.

    I would love given time to learn how to send data with the LoRa module and pic but that's for the future and a lot more learning my...
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    Re: Active low transmitter question

    'No. Only when there is a state change. We said that.'

    Yes you did Ioannis, I'm just trying to understand the mechanism here.

    'You should care only for your logic state. And maybe your voltage...
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    Re: Active low transmitter question

    'the state will remain high till Vin is less than or equal vil where its guaranteed to go low'

    So switching Vin LOW (from pic) causes a Tx?

    And

    Transmitter will continue to Tx until Vin goes...
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    Re: Active low transmitter question

    'a high state is maintained until vil is reached'

    Ok, cheers, so:

    If an input pin on the transmitter is internally held HIGH and you put an external HIGH onto that pin (from the pic) no Tx...
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    Re: Active low transmitter question

    'you might want to send a heartbeat to indicate tx link is active and working'

    Good idea.

    'why the tx once only obsession ?'

    Not an obsession, I'm just trying to understand the mechanism...
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    Re: Active low transmitter question

    So to make the transmitter Tx once only, the way to do it is just have one pin state change - High to Low or Low to High?
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    Re: Active low transmitter question

    Hi Richard

    I got the idea of a Tx being initiated from the Data sheet 'When configured as transmitter: Pins 3, 4, 7, 8, 9, 11, 12, 13 Inputs are internally pulled high, active low'

    But as you...
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    Re: Active low transmitter question

    Ok - So the transmitter will always Tx twice, on a button press to ground, then open contacts (if using a button). Or a transition from HIGH to LOW to High if using a pic GPIO pin to cause a Tx,...
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    Re: Active low transmitter question

    http://www.rfsolutions.co.uk/downloads/1623336683DS-GAMMA-12.pdf

    Ioannis / Richard - Hopefully I've uploaded a link to the RF Module (PDF was too large to upload directly).

    It looks like there...
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    Re: Active low transmitter question

    9057

    Here's the Rx schematic. When an Rx is received it outputs 5v onto the corresponding pin, which will then be read by the pic.

    My question now is (and this should have been the question all...
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    Re: Active low transmitter question

    "what is your doubt ?

    the data so far indicates no need for pullups , the schematic shows none.

    a pic pin when configured as output will never "float" its either high or low when set"


    Hi...
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    Re: Active low transmitter question

    Hi Ioannis - Looking back at the thread I've done a pretty miserable job of it so far certainly information wise and I apologise to everyone.

    *I think it would be best to have the Data sheet of...
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    Re: Active low transmitter question

    Thanks for your help mpgmike, anyone else have any thoughts on this?
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