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Thread: Wireless mesh or tree network, need advice.

  1. #1

    Wireless mesh or tree network, need advice.

    First things first, I am completely ignorant when it comes to wireless ( WiFi ) networks, I have a very loose grasp on terms like server, client, access point, etc. for the sake of this post, assume Iím a 5 year old.

    I have played around with Bluetooth modules, LoRa and Esp32 to some extent, but never more that point to point.

    I have a project in mind that would be an awesome tool for work if I could implement it.

    Basically, I have multiple machines, generally 6-16, that all have an auxiliary fueling system on them. They usually run on diesel, but have been upgraded to be more ďgreenĒ an are outfitted to run on natural gas.

    This system is quite finicky though, and requires constant supervision.
    A wireless mesh type network, that would simply monitor the on or off state of 4 indicator lamps, and report it back to either a web page or a dedicated teensy powered ď something with a screen ď would save hours of work and miles of walking.

    So the basic set up, say 12 nodes, all talking to 1 device, and simply sending a few bytes of data to indicate the unit number, and the status of 4 digital inputs.

    We have a fleet of around 30 pieces of equipment, but generally no more than 10-12 are in the same place.

    And the area that needs to be covered is never more than 100 yards.

    So my thought was, a Lora mesh network, feeding back to a central display. If I could somehow get all the data from all the nodes to show up on a cell phone or laptop, even better, but that might add more complication than itís worth.

    So I thought I would ask, to see what advice you all might have. Low power is not needed.

    Thanks
    Joe

  2. #2
    Senior Member+ Frank B's Avatar
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    If you want it really reliable, maybe think about GSM. It has the additional advantage that you can send a SMS to your cellphone.

  3. #3
    Frank, thanks for the reply. I don’t know much about GSM, had to look it up just to make sure.
    I’m guessing that it would need cell (phone) coverage to work?
    If that’s the case, that won’t work as 50% of the time we are working where there is poor to no coverage. If not though, that might be a good way of doing it.

  4. #4
    Senior Member+ Frank B's Avatar
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    Oh, in this case, loRa is better. Or WiFi.

  5. #5
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    For this purpose there are several paths:
    A. Build on LaRa. This requires LoRa transcievers and a microcontroller plus power supply and signal interface on all endpoints, plus a central with a microcontroller to display the data or convert them o be transmitted over internet.
    B. use Bluetooth. Yes. You write the devices are 100 yards away. Away from each other, or away from a central? What you need would be a pair of cheap bluetooth modules like HM-13 for each device, one on the remote and one on the central, both paired to each other. Very simply you could use serial to communicate data or even just use the built in features of a HM-13 to display the status of PIO signals. No microcontrollers and no additional software needed. A bit of signal interfacing to make the lamp signal compatible to the PIO input, power supply, some LEDs to reflect the status of the remote on the central. To extend the range of the HM-13, just add external antenna. Any cheap WiFi antenna could do, as Bluetooth is 2.4GHz like WiFi.
    C. use ESP8266. Each of them can act as access point and client, also they can be programmed to form a autoconfiguring mesh that transports data over a WiFi network to a webserver or act as webservers themselves. The displaying device could be a phone or tablet or even an other ESP connected to the network. This approch is very versatile and can be used to monitor even over very long distance, if you just add some cheap commercially available WWAN routers.

  6. #6
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    I forgot:
    to B. It is also possible to use one microcontroller, preferrably Teensy and only one HM-13 on the central to scan all the peripheral HM-13 modules.
    That way you could use one central antenna or use a homebrew dish antenna with the HM-13 in the feed position to cover a mile or more of distance.

    Important is the selection of the proper hardware. ESP32 may be more powerful, but it can not do mesh, while the simple ESP8266 can.
    Or with Bluetooth, you could use any generic module and do complicated additional microcontroller and protocol stuff, or use the HM-13 that has functions as central and peripheral, can transmit parallel IO directly without extrernal control, does automatic reconnect and is pairable to an other HM-13, has enough power and features different protocols.

  7. #7
    I have a nearly identical system setup in my house. A "base" monitors several "stations" for things like if my garage door is open, outside temp, etc. I use E44-TTL-100 modules. Each station has it's own ID. The base sends an info request to ID=1 gets a response, then sends an info request to station ID=2 and so on. Each station is programmed to only process incoming requests for it's ID. The base then processes each info packet and displays Door open/door closed etc.

    I also have buttons on the base that let me close a garage door. in this case, base sends info but with a flag. The appropriate station gets the request, sees the flag and triggers a relay to close the door.

    I wrote a lib for the E44 to make programming them easier.

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