Transfer multiple voltage measurement wireless

Discussion in 'The Projects Forum' started by mrbond, Sep 4, 2016.

  1. mrbond

    Thread Starter New Member

    Sep 4, 2016
    3
    0
    Hi,

    I need some help with my project.
    I have not worked considerably with electronics since I graduated 20 years ago, but I hope to start again now.

    My project is as follows:

    I need to measure voltage on up to one hundred locations. Each transmitter must send an uniqe ID and the measurement result once, or severla times every 24 hours.
    It is not important how often the result it transmitted as long as it consumes minimal current.
    The results needs to be transmitted wireless to a receiver or several receivers if the distance is to long for one receiver.
    From the receiver the result will be sendt to a web page.

    As a receiver I can use a computer like Rasberry pi, Arduino or similar. Other ideas are also welcome.

    My first challange is to get the transmitter sendt an uniqe and the measurement result.
    Can anyone please give me any tips or directions on how to start ?
     
  2. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,802
    832
    First, how many bits are needed to distinguish 100 different locations?

    Second, what is the voltage range being detected?

    Third, what accuracy do you need to identify the voltage at?

    Once these are answered, one can begin to develop a communications protocol.

    (These are serious questions; not rhetorical ones)
     
  3. mrbond

    Thread Starter New Member

    Sep 4, 2016
    3
    0
    Thank you for a prompt reply,

    If we use 8 bit, we can get 256 locations. Then we dont need to expand in the future :)
    Voltage range is 10-14 volt
    Accuracy needs to be 1 volt, no decimal

    Cheers :)
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    You didn't specify the maximum distance for the wireless.
     
  5. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,802
    832
    So you need to transmit 2 bytes of data (1 byte and a nibble). Add a prolog byte. The voltage nibble could have the other nibble set to 0xF as an aid in validating data received.

    So your monitoring station needs to measure the voltage, map it from the ADC range to 0-16, and transmit wirelessly when polled (to prevent collisions). The master station will poll and parse the data received for a valid packet.

    The part of your requirements that is tricky is using repeater stations.
     
  6. mrbond

    Thread Starter New Member

    Sep 4, 2016
    3
    0
    Thanks for the replys,

    The range for wifi needs to be 200 merters +

    I have bought a raspberry pi 3 and some transmitters and receivers on ebay.
    They are in transit now.

    My challenge now is how to generate the two bytes that I need to send.
    Is it possible to use a analog to digital converter for the voltage? And add a uniqe ID in the second byte ?
    Can anybody give me a hint on how the first step can be done ? Transform the voltage to 2 byte of data ready for transmitting ?

    Thanks :)
     
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