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Help! Load Cell with Leobodnar board

Discussion in 'Sim Racing Hardware' started by Bitacaia, Jun 5, 2017.

  1. Bitacaia

    Bitacaia

    Messages:
    27
    Ratings:
    +14
    Hi,
    I have recently made a DIY Hydraulic Handbrake, but unfortunately it stop working (need to make an autopsy). So i decided to attach a load cell (the same used in the Fanatec CSP V1) to the Handbrake using the Leobodnar board "BU0836-LC".

    Example of the loadcell:
    https://www.aliexpress.com/item/FRE...lgo_pvid=4ec473f6-c5ee-4aca-8e33-a879bd92ad54

    But unfortunately I cannot have any reaction in Windows when I connect the board. I tried to connect in the normal analog ports, no result... I tried to connect to the Loadcell amplifer port, no result...
    NOTE: the board is working, just the analog axis doesn't move, although it detects something connected.
    To check if the loadcells are working, I attach them to the my pedals, and they work...
    I even played with the wires position, inverting in all combination possible, with no result...
    I have no idea what can i do next...

    So, the question:
    With this specific Loadcell, is mandatory to have a Amplifier? Or, i can connect directly to the analog ports?
    So, please help me with this problem!!!

    Tiago Viana
     
  2. winet

    winet

    Messages:
    34
    Ratings:
    +9
    Your Fanatec load cell is not compatible with the Bodnar board . You would need to use a standard load cell with 4 wires.
     
  3. Bitacaia

    Bitacaia

    Messages:
    27
    Ratings:
    +14
    So, update about the problem.

    I will use basic language because i don't understand much about electronics.

    The problem is: The load cell from Fanatec or "toilet scale" only uses 3 wires. But the load cell amplifier requires a 4 wires connection. (called Half Bridge)
    So, is require to connect something between to transform it 3 to 4. Leo Bodnar offers a PCB with this function. But it will cost me 20€ to have it at my door.

    I found on the internet some alternatives to the LB board.
    One requires a setup with 2 LC (already tried and it works, but i need to have a extra LC hanging around, doing nothing).
    The other, some how, i connect 2 1k Ohm resistor. Unfortunately i could find a good tutorial with this setup. I found 2 setups, but it didn't work.

    I will keep posting my challenges!

    Tiago Viana
     
  4. 3ller

    3ller

    Messages:
    85
    Ratings:
    +20
    i think you can use the load cells stacked in parallel and you will have 2 times the capacity so a 100 kg load cell, give it a try.
     
  5. Bitacaia

    Bitacaia

    Messages:
    27
    Ratings:
    +14
    Hi!
    So, good news. I solve all the problems. In one forum i read that i needed to use 1k ohm resistor, but didn't work.
    So, luckily i had some 10k ohm resistor around, and it worked. So, no need to have two LC connected. I will make a schematic of this, for people with interest on this subject.

    Note: my knowledge of electronics, don't allow me to explain why 1k isn't good and 10k is... so, don't expect me to answer any complex question... :)