Farmo technology is not intended to replace human oversight but can allow much more frequent monitoring and provide historical insights for analysis.
By Farmo

Water Rat (Trough and Tank Sensor)

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GST included.
  • Description
  • Specs
  • Design Background
  • Farmo's Water Rat (patent pending) is the world's easiest to set up tank and trough water sensor on the market. It comes with a Telstra NB-IoT SIM card inside so you can just throw it in a trough, or tether it to a tank, and start getting low water level alerts on your phone or computer right away. When it's floating in a trough, cattle will inspect the Water Rat then quickly leave it alone once they realise they can't push on it (and break it) like a fixed object.

    good design award

    30 Day Free Trial: Sometimes you just need to see it, to believe it.
    Try the Water Rat on your farm, with your animals, for 30 days. If for any reason, you are not happy, return it to us free of charge for a full refund. Full details here.

    How it works:

    The Water Rat looks simple but has some smart technology inside including an accelerometer tilt sensor to detect movement, an NB-IoT chip to send data, and GPS to report location. When the water level reaches a low point, the Water Rat tilts over and sends an alert. When the water level rises another alert is sent to let you know the water is OK again.

    Data is sent via NB-IoT which is the long-range, low-cost version of 4G for IoT devices. The signal for NB-IoT travels further than 3G/4G, so if your mobile phone has any reception on site, then NB-IoT devices will work there. Additionally, NB-IoT transmit on a lower frequency than cellular mobile so penetration through buildings and cement tanks is better.

    When you receive your Water Rat jump online to activate your subscription which covers the data, dashboard and alerts for a year. 

    Monitoring stock water can be made more efficient by technology and allow much more frequent observations. However, human oversight can never be replaced when animal welfare is at stake.

    Installation Instructions [download]

    Product Data Sheet [download]

  • Sensor Details

    • 9-axis accelerometer
    • GPS 
    • NB-IoT Telstra certified module
    • 14,000 mAh Li/SOCl2 non-rechargable battery for long-term use
    • 1.8m tether rope not included (purchase here)

    Data Subscription

    • Each Water Rat requires a Farmo subscription.
      Includes Farmo dashboard and alerts.
    • Visualise data and set alerts on your PC, laptop or phone.
    • Display when water level above or below your trigger point.
    • Set custom alerts via email (free) or SMS (10c each).
    • Send alerts to different people at different times as required.

    Application areas

    • Stock water troughs
    • Water tanks
    • Agricultural, Household, Industrial, Smart City, Ag-tech
    • Flood detection

    Care and maintenance

    • Tank or trough should be free of objects that could catch, hold or prevent the Water Rat tilting.


    • All Farmo products include a 12 month warranty as standard.

  • We know from experience that a fixed trough sensor has to be incredibly strong to resist the force of a 1-tonne bull. So for the Water Rat we used a different idea of strength inspired by the Ping Fu quote: Bamboo is flexible, bending with the wind but never breaking, capable of adapting to any circumstance."
    i.e. If an object is floating, it has no resistance to the force applied to it. The most an angry bull can do is nudge the Water Rat around with its nose.

    Secondly, a fixed sensor requires tools and skills resulting in a permanent or semi-permanent installation. Farms may have more than fifty troughs used in rotation, so that requires a lot of sensors. With Water Rat the idea is that you can just pick up and move the sensor when you move the mob.

    Finally for tanks, reaching the bottom and tilting is not ideal so we use the simplest possible solution in the form of a tether that attaches to the Water Rat and to the side of the tank. The length of the tether determines the depth at which the Water Rat will tilt over and alert. Most farmers set this up for 50% full or empty, but it's up to you.

    The Water Rat was not our first attempt to monitor water levels in troughs. We went through a few iterations of fixed-in-place models which we thought at the time were pretty good. However, during installation one day, we received the feedback that the sensor was OK but a lot of customers would struggle with the lengthy and complex installation. One customer told us: "It would be great if we could just throw it in the water". We agreed, that would be great. We considered it for a while and had to try it out. That's when we started thinking about the Water Rat.

    Some photos along the way

    The fixed in place model
    fixed in place

    The first floating PVC pipe version
    WR poly pipe

    3D print that was too floaty in the base

    Folded aluminium keel solved the flotation problem

    Lots and lots of field testing

    A 3D print of the final shape for more testing...3d printed model

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