The new Agriculture Sensor Board extends the award-winning Waspmote platform by supporting the measurement of the following key parameters: air temperature, air humidity, soil temperature, soil moisture, leaf wetness, atmospheric pressure, solar radiation, trunk/stem/fruit diameter, wind speed, wind direction and rainfall. The board allows more than ten sensors to be connected at one time. Libelium’s CTO, David Gascón says “A Waspmote sensor network using the new board can measure irrigation effectiveness, crop growth and micro-climatic conditions as well as detect adverse weather events”.
Local variations in soil, drainage and evaporation can mean that irrigation is not uniformly effective. For example it is possible that, within a vineyard, some vine roots are too dry while others are waterlogged. If three soil moisture sensors are simultaneously placed at different depths the local water retention in the soil can be assessed. By measuring evapotranspiration it is possible to work out how much irrigation water is being actually absorbed by the plants. Using sensor data to automatically adjust irrigation to match local conditions conserves water and is equally applicable to vineyards, greenhouses and golf courses. Avoiding over-watering also helps prevent certain crop diseases including rot, fungi and bacteria which thrive in wet conditions.
Precision agriculture aims to optimise production by taking account of local soil and climatic variations. David Gascón says, “This new board enables vineyards to be controlled with a finer granularity than existing precision agriculture techniques”. He explains, “Accurate dendrometers, capable of measuring changes in diameter of a few micrometres, allow the measurement of water intake of individual vines from irrigation. Using a PAR (photosynthetically active radiation) sensor checks the conditions for photosynthesis”. The Agricultural Sensor Board is also highly applicable to greenhouses where the creation and control of microclimates is important to the growth of delicate crops such as exotic fruit. For mushroom farming, Waspmote’s Agricultural Sensor and Gas Sensor boards can be used together to measure and control soil moisture and temperature, CO2 level and air temperature.
The board also supports meteorological sensors such as air thermometer, hygrometer, anemometer, wind vane and rain gauges (pluviometer). If the temperature falls below a threshold, heating can be automatically started by the wireless sensor network. Meteorological sensors can trigger warnings in the event of adverse weather such as high wind or torrential rain. Waspmote does not need to monitor values continuously and can spend long periods in a power saving mode. However if wind exceeds a threshold the anemometer will send a signal to wake up the Waspmote board. In hibernate mode the board consumes just 0.7 microamperes current resulting in outstanding battery performance. Should continuous measurement be required, a socket enables the board to be powered by a solar panel also available from Libelium.
Agricultural sensor networks using Waspmote send data using ZigBee (using 2.4GHz, 868MHz, 900MHz frequencies). The radio range depends on undergrowth but can be up to 12 km for line of sight links or up to 6 km for non line of sight. Alarms can also be sent to the mobile phone network using Waspmote’s GSM/GPRS board.
Waspmote users – such as agricultural consultancies - can add value layers to the platform by using the open source API and programming environment. This enables the platform to be easily integrated with third party applications. It can also be extended by addition of different types of sensor.
Waspmote was chosen by Sensors Magazine as one of the most exciting new products at the recent Sensors Expo & Conference in Rosemont, Illinois. Libelium received a Sensors 2010 Best of Sensors Expo Award in the Data Acquisition Products category.