Design of plant pest spraying machines using solar cell power

Plant pest spraying machines are now starting to develop using a variety of technologies ranging from diesel to electric power. However, this technology has problems such as limited fuel capacity in diesel engines and a lack of electricity demand for electric batteries. If the sprayed area is too large, the capacity for fuel and battery requirements is insufficient. In this study, we will explain how to apply solar cells to make a plant pest spraying machine so that when spraying will occur simultaneously the process of charging or charging the battery by solar power So that the need for battery capacity is met for spraying over a large area. The process of making this tool is done by assembling several components such as solar panels, SCC (solar charge controller), spray tanks and lithium batteries.


Introduction
Spraying is a very important job in a farm. Spraying pesticides has aim to protect plants from insect attack [1]. In spraying farmers usually use a hand operated spray pump or fuel. This conventional spraying causes casualties or tired toward the user because the construction is too heavy and impractical in hell. This motivates researchers to design and model a spray machine that uses solar power. In this design we have another objective to overcome the level of casualties in handling when doing spraying, to reduce the level of vibration when still using a fuel-operated spray pump, to produce an environmentally friendly spray machine due to fuel removal [2].
Nowadays, many non-conventional energy resources used daily, one of them is solar energy. Solar energy is available in natural unlimitedly. Indonesia is in equator, so the solar energy is quite high potential because the sun shines in the whole year. The sun shines about 6 to 8 hours per a day. Meanwhile the ideal length of time to produce electricity for solar panel is 4 to 5 hour per day. Pesticide sprayer using solar energy can save the cost more than previous sprayer or conventional sprayer. Principally, this solar-energy sprayer absorb solar energy using solar panel which contains photovoltaic cell, then the solar energy will be converted into electrical energy. The produced energy will be stored in a DC battery in a form of voltage afterword it will be used to work the DC pump of sprayer machine [3].

Research design
The research used some methods, those are study of literature, experiment, and observation., Afterward the researcher conducted planning or constructing some tools or equipment. Then the researcher conducted testing the tool and observed the parameter.

Research process
The following is the procedure in research as, The first step is to start, then the second step is to study the literature. At this stage the researcher collects data directly from reference journals and books related to solar cell-based spray machines. In the third stage, the researcher identified the problems in the field related to the spray machine, what are the constraints in agriculture, both in terms of time and cost. After knowing the problems in the field, the researchers tried to plan an appropriate sprayer in the field based on farmers' constraints so far. Then the fifth step is for the researcher to design a solar cell-based spray machine which is used as an alternative to solve the spraying problem in agriculture. Then the researchers purchased several components of the spray machine and solar cells, after which they made solar cell support equipment. after the equipment is complete the next step is to assemble a solar cell-based spray machine. The next step is testing the tools, while testing includes spraying time with a volume of 15 liters of water with three types of nozzles. the second test is to measure the discharge of water sprayed by each nozzle. when the test is successful it is continued for data collection and collection. if it does not work, a new design is planned. if the tool is successful and gets the data, the next step is data processing. Data processing is done by collecting all test data that is done with the help of Microsoft Office. Data processing can be presented in tables and graphs, then data analysis is carried out to determine the performance of the spraying machine, water discharge and how long it takes to spray. After the data analysis is complete, the researcher can draw conclusions. After knowing the conclusion, the research is considered complete. Figure 2 shows design of solar energy sprayer machine figured by software inventor. In the picture of this solar cell-based spray machine there are several components, including: Solar panels, spray tank, battery, nozzle, indicator battery, on-off switch, motor switch, dc pump, charger from home electricity. The volume of the tank is 15 liters, this tank is not made but is already available in the market under the brand Matsukawa Japan Technology.while the solar panels used have a size of 10 Wp. In the design of this tool is made simple because to facilitate the performance of users in the field.

The component of sprayer machine
a) Solar panel Solar energy is unlimited renewed environmentally friendly energy. One of the important components produced energy is solar panel. Solar panel has a function to change sun shining become electricity caused by attraction between electron in the silicon using photon of sun shining [2].

d) Battery
Electrical battery is a device which has function to storage the energy which is produced from solar panel. when the battery supplied electrical energy , positive terminal is a cathode and negative terminal is anode [4]. The type of battery used in this study is a lithium battery with serial number 18650 with a voltage value of 3.7 volts and a current value of 2400 MAh. This solar cell-based spray machine uses 6 batteries arranged in series and parallel which are attached to the holder.  Figure 6. Battery e) Nozzle Nozzle is a device to control the flow or characteristics of fluid flow (especially to increase the speed) when coming out (or coming in) closed pipe. Nozzle is often in form of pipe or tube with varying cross-sectional areas and can be used to direct or modify the flow of fluids (liquids or gases). Nozzles are often used to control flow rate, velocity, direction, mass, shape, and / or flow pressure.

Figure 7. Nozzle f) DC Pump
Pump is a tool used to move fluids mechanically system. In moving fluids, pump needs power to move mechanically system [2]. This pump has two canals; inlet and outlet.  Figure 9 shows a work series of solar cell-based sprayer machines which consist of 4 main parts, namely energy conversion, energy storage, DC drive and sprayers. The first unit of the system is called the energy conversion unit, in which there is a change in solar energy into electrical energy which is carried out on the solar panel with a photovoltaic effect. The current generated in the solar panel is DC (Dirrec Current). After the solar panel is connected to the SCC (Solar Charge Controller) which has functions to manage the incoming voltage on the battery so that the incoming voltage on the battery is constant and stable. The output from the solar panels is used to charge the battery [5]. Then enter the second unit, it is storage process. The power storage process uses a type of lithium battery with the serial number 18650. From the battery, it is then connected to a battery indicator which has functions to read several parameters such as voltage, current and resistance. After from the battery output, then it is connected to the DC pump. The DC pump is used to suck and drain the pesticide liquid in the tank. To activate the pump you can use a pump / motor switch. The pump rotation can be adjusted from the motor RPM switch; the goal is to produce a strong spray. Then enter the last part, namely the sprayer or sprayer. Spraying this pesticide liquid through a nozzle hole, this component functions to regulate and direct the flow rate of the pesticide liquid.  Figure 10 shows the final result of assembling a solar cell-based pest spray machine. The assembly process begins with the manufacture of a solar cell frame made of iron in which the solar panels are attached to the frame with rivets, then the frame and solar panels are attached to the top of the spray machine tank. The tilt of the solar panel can be adjusted using a support rod made of iron, the slope of the solar panel can be adjusted with an angle of 200, 300 and 400. Furthermore, the solar panel is connected to the SCC (solar charge controller) and the battery, so that the battery can be charged with voltage from solar panels. From the battery, it is connected to a pump which functions to suck the pesticide liquid mixed with water through the nozzle.

Calculation surface area on solar panel
To calculate the input power of the reaction intensity of solar radiation, we must first calculate the surface of the solar cell module. In which, the solar cell module has a length of 30 cm and a width of 21.3 cm. After found the length and width, you can calculate the PV area with the following formula.

Input power from intensity reaction of solar radiation
Input power is the power generated in an area of solar panels due to exposure to solar radiation. This input power is also often referred to as the energy produced by solar panels. The input power can be obtained from the multiplication of the panel area with the intensity of the sunlight.

Fill factor (FF)
Fill factor is important parameter for solar cell, it can be defined as maximum power output (ܸ ‫ݔ‬ ‫ܫ‬ ) is divided to the score of Voc and Isc [8].  The following table is a table of the results of testing tools to find out which sprayer takes 15 liters of water. In testing, it used 3 types of sprayer; sprayer 1, sprayer 2 and sprayer 3. Those three types of sprayer that distinguishes is the shape of the sprayer and its dimensions. The following table shows the duration of spraying.  Table 1 shows that the sprayer on a spray machine that takes the greatest time to spend 15 liters of water is sprayer 1 with duration 11 minutes 30 seconds. While the sprayer that requires the shortest times of spraying is sprayer 3 with duration 7 minutes 30 seconds. The duration of this spraying is influenced by the amount of each hole in the sprayer. The greater the number of holes in the sprayer, the greater the water come out so that the spraying time is shorter, and vice versa.  Table 2 shows the results of the flow rate test at the nozzle. The nozzle flow rate can be obtained from the ratio of the volume of water in the spray tank to the length of time required during spraying. In table 2 the smallest nozzle flow rate occurs in sprayer 1 with 1.33 liters per minute. While the largest nozzle flow rate occurs in sprayer 3 with 2.05 liters per minute.

Conclusions
The pest spraying machine based on the solar cell was successfully made. This system was developed in order to increase the working capacity of farmers by reducing the time and fatigue of the hands of a farmer in pumping the sprayer machine. The operation of this sprayer is very simple and environmentally friendly. The advantage of this tool is that it can charge the battery directly when spraying during the day.