Save water (and money) with IoT

The goal of this project is to test and improve an IoT (Internet of Things) application to enable farmers to save up to 30% water. In other words, I want to provide a tool to better manage soil irrigation in real time, save the cost of pumping while increasing your yield.

To achieve these results, I am using a promising technology: LoRaWAN. This technology is particularly interesting because it allows long-range transmissions (more than 10 km in rural areas) with very-low power consumption.

In the current experiment, two stations (nodes) are equipped with

  1. three Watermark tensiometric sensors, to measure the water content of the soil in kPa (6 Watermark sensors for the second station)

  2. one sensor for measuring soil temperature

  3. a rain gauge to count the drops delivered by the water-drip system.

  4. one sensor to measure air temperature, atmospheric pressure and humidity

  5. one sensor to measure the brightness (luminousity?)

  6. an IR sensor (in test phase) to measure the bud temperature)

On the second station, we added 3 additional tensiometric probes, 6 in all, positioned to observe the formation of the water bulb that will be formed with the arrival of heat and watering.

Every hour, the stations take the measurements and send them to the gateway, which processes the received data and transmits them to a remote server. A web interface will allow the farmer to view the status of their crop, from their smartphone, and in real time, from anywhere, such as during your breakfast.

Thus, it will be easier to choose the right moment to irrigate your soils, and to calculate the water needed.


We want more

I still wish to improve the project. Lanscape configuration plays an important role in data transmission. For example, a hill, a forest, the an elevation difference between the station(s) and the gateway, can interfere with data transmission.

A station too far from the gateway, taking also natural obstacles into account, will be unable to transmit data via the gateway. To remedy this problem, an additional gateway would be needed together with the necessary battery, solar panels and SIM card.

However, using LoRaWAN technology, it is possible to create a gateway-repeater with much-lower cost and with an extremely long battery life (in years) using only a 3000mA Lithium battery. In that way, we can make sure that the transmission of data is optimal with respect to the relief of the ground, with a cheaper device than an additional gateway.

Finally, I wish to make use of this coming summer to improve the stations, such that they will run during the following winter season, especially to monitor the temperature of the buds and on the consequences of late frost.

I want to acquire new sensors, ie, a pyranometer (to measure solar radiation), an anemometer (wind speed) and an infrared temperature sensor, to test the evapotranspiration of the plant.

IMPROVEMENT AND FINALISATION Electronic circuits are being replaced by a new and improved model:

  1. replacement of a circuit consuming too-much battery power

  2. modification of the programming of the microcontroller to improve the autonomy (58 minutes in sleep mode every 60 minutes).

  3. improved timing of measurements with a Real Time Clock (RTC)

  4. improvement of the power-supply mode of the tensiometric sensor, to have a more-precise result

  5. new custom PCB and smaller

  6. integration of the barometer and the luxmeter into the PCB

  7. Replacement of some connectors for easier mounting and connection of sensors

  8. Improved display of measurements on an LCD screen (display page-by-page)

  9. Using the SD card to save the module settings

Finally, I improved the web application (See rewards) with a more user-friendly display in the form of better graphics. This web application will need further development, especially for alarm management, when the soil condition has reached the critical threshold.

A FEW WORDS ON IRRIGATION SENSORS The Watermark ® tensiometric sensor calculates the water content of the soil in kpa. In other words, the suction force that the root must exert to extract water from the soil.

It is a robust and relatively inexpensive tool, which does not require any particular maintenance. It is easy to use and the measurements are precise. Its construction is adroit: a perforated cylinder made of stainless steel that supports a permeable membrane. Inside, there is a compact sand aggregate: the «granular matrix». At one end, a gypsum board and electrodes connected to two wires are placed to emerge on the surface of the ground. The gypsum board serves as a buffer against the differences in acidity and salinity of the soil, so that the electrical resistance operates between the electrodes which depend solely on the temperature of the soil.

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Why supporting me

Your support is important to me. It will allow me to provide farmers with a tool to better manage the irrigation of their fields, in real time, and thus save on the cost of pumping and save up to 30% water.

It will also allow me to finance the realization of a relay station to optimize the transmission of data when the configuration of the ground creates obstacles. Finally, it will allow me to finance the planned improvements, and for the rest, cover the expenses already incurred.

I also want to replace the current gateways for a much more powerful and certified one.

As I wrote, It will mainly allow me to finance new stations (at least part of them), with the aim of extending this solution to neighboring farmers, and thus create a working group to perfect and finalize the operation of the solution.

  • 3 Watermark probes (Sfr 45 .– per probes)
  • a station (+/- Sfr 100 .–)
  • a gateway (+/- Sfr 550 .–, incl 12V battery, solar panel, solar controller, concentrator, raspberry, antenna, etc.)

But also, it will allow me to cover some expenses:

  • purchase of components to realize the gateway-relay and thus dispense with a second expensive gateway
  • communication campaign aimed at people of the profession to make known the interest of this project (newsletter, mail, flyer, poster, announcements)
  • participation in the annual conference (2020) The Things Network, Amesterdam. (This conference is very important because it is presented very enriching workshops and conferences (I participated in the 2018 conference))
  • financing of the new and improved printed circuit board (PCB) and its components

To prevent late frost (March-April 2020):

  • purchase of components to monitor bud freeze
  • purchase of a pyranometer, to measure solar radiation
  • infrared probes to measure the temperature of the buds
  • Subsidiary purchases

To cover some expenses already incurred

  • purchase of a soldering oven to assemble the new stations
  • Financing the Watermark Reader to verify and validate soil moisture measurements
  • Financing of the new printed circuit board (PCB) and its components
  • and all the electronic equipment necessary for the realization of this project, modules (soldering iron, magnifying glass, pliers, modules, probes, electronic components, etc …), including subsidiary purchases
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