Ultrasonic sensor-based automatic control volume sprayer for pesticides and growth regulators application in vineyards

A study was conducted to design a sensor-based control volume sprayer for vineyard cultivation. The study aimed to develop cluster-specific pesticide and growth regulator application systems with improved penetration and minimum off-target losses, thus saving chemicals and overall cost. For the determination of design values of the control volume unit, physical properties (cluster length, width, and level of compactness) of grape clusters from seventeen major genotypes selected from vineyard research farm ICAR-IARI New Delhi were studied. For the design of the grape cluster detection unit, two different types of sensors, i.e., ultrasonic sensor (HC SR-04) and infrared proximity sensor (B0115NCT4U), were evaluated for their ability to detect the target (grape cluster) and the response time. The design of the spraying unit for the control volume sprayer also involved selecting suitable nozzles and operational parameters. The developed sprayer was evaluated for application of plant growth hormone (Gibberellic acid), and the performance was assessed in terms of droplet size, chemical application per cluster, cluster and berry growth characteristics, sprayer application rate, uniformity coefficient, and application time. The data on the physical properties of grape clusters revealed a maximum cluster length and width of 24.00 +/- 0.91 cm and 18.80 +/- 0.15 cm, respectively. The ultrasonic sensor had a comparatively higher sensing range, beam angle, and lower price than the infrared sensor. The spray uniformity for the hollow cone and flat fan nozzle varied significantly for the operating pressure range of 2-4.5 kg.cm(-2). The developed sprayer consisted of a 3D printed control volume unit, ultrasonic sensor, two flat fan nozzles, microcontroller (Atmega 328P), relay switch, voltage converter, spray tank of 16-liter capacity, and 12 VDC battery. In case of developed sensor-based control volume sprayer, 30% and 35.48% saving in chemical use and application time, respectively, were observed compared to the conventional dipping method. The PGR application method has significant interaction with cluster length and berry growth as the main effect; however, failed to show a significant interaction with cluster width. Maximum cluster growth (16.89 +/- 1.72 mm) was observed in PGR application with a developed sprayer.