Development and Construction of an Automatic Fish Feeder

475 Nigerian Research Journal of Engineering and Environmental Sciences 10(2) 2025 pp. 475-485 p ISSN: 2635-3342; e ISSN: 2635-3350 Original Research Article Development and Construction of an Automatic Fish Feeder 1Linus, G.S., 1Olagbegi, P.O. and *2Ehimemenn, J.I. 1Department of Mechanical Engineering, Faculty of Engineering, University of Benin, PMB 1154, Benin City, Nigeria. 2Department of Production Engineering, Faculty of Engineering, University of Benin, PMB 1154, Benin City, Nigeria. *joewealth.ehim[email protected]; [email protected] http://doi.org/10.5281/zenodo.18061581 ARTICLE INFORMATION ABSTRACT Article history: Received 04 Oct. 2025 Revised 01 Nov. 2025 Accepted 09 Nov. 2025 Available online 30 Dec. 2025 Nigeria faces a persistent fish supply deficit, making aquaculture expansion essential for food security and economic growth. However, manual feeding in fish farming remains labor-intensive, inconsistent, and inefficient, often resulting in feed wastage, poor water quality, and reduced productivity. To address this challenge, a solar-powered automatic fish feeder was designed and fabricated using locally sourced materials such as Polyvinyl Chloride (PVC) and Teflon to ensure cost-effectiveness, durability, and ease of maintenance. The system comprises a screw conveyor driven by a 12 V DC motor powered by a rechargeable battery, which is sustained by photovoltaic cells. With a storage capacity of 6 kg and dispensing capability for feed sizes of 4–6 mm, the feeder delivered an average of 0.89 kg per minute during tests. Performance evaluation demonstrated 99% efficiency, minimal feed loss, and reliable operation across different feed sizes and intervals. Compared with existing imported feeders, this prototype offers a more affordable and adaptable solution for smalland medium-scale Nigerian fish farms. The innovation not only reduces labor costs and feed wastage but also contributes to sustainable aquaculture practices and enhanced fish growth performance, highlighting its potential as a scalable technology for improving food security in resourcelimited settings. © 2025 RJEES. All rights reserved. Keywords: Automatic fish feeder Aquaculture Solar energy Efficiency Feed dispensing Sustainable design 1. INTRODUCTION Nigeria continues to face a significant fish supply deficit, with estimates suggesting a shortfall of about 2.5 million metric tons annually (Ogunji et al., 2023). Expanding aquaculture is therefore critical to enhancing food security, generating employment, and supporting economic growth. However, persistent challenges hinder productivity, among which feeding management remains one of the most pressing (Okon et al., 2025). In many smalland medium-scale farms, feeding is still performed 476 G.S. Linus et al. / Nigerian Research Journal of Engineering and Environmental Sciences 10(2) 2025 pp. 475-485 manually, a method that is labor-intensive, irregular, and prone to human error. Overfeeding wastes feed and deteriorates water quality, while underfeeding reduces growth and overall yield (Ozigbo, 2013; Fasoyin et al., 2021). Automatic feeding devices have been explored since the 1960s (Arthur, 1962) and remain central to modern aquaculture practices. Several prototypes and designs have been reported (Yeoh et al., 2010; Wei, 2017; Osueke et al., 2018), but many suffer from limited efficiency, poor adaptability, or operational complexity in small-scale settings. More recent advances highlight the integration of electromechanical control, IoT, and renewable energy sources to improve feeding precision and sustainability (Hassan et al., 2023; Rahman et al., 2022; Adegbite et al., 2023). These systems deliver programmed quantities of feed at controlled intervals to optimize growth and feed utilization (Thornburg et al., 2025; Shaari et al., 2018), with some models incorporating vision systems and algorithmic control to adapt feeding to fish behavior and environmental conditions (Sobri & Topiq, 2024; Son & Jeong, 2024; Aljehani et al., 2023). Nevertheless, in Nigeria and similar tropical, resource-limited settings, the adoption of automatic feeders is extremely low. Contributing factors include the high cost of imported devices, lack of designs adapted to local pond structures and unstable power supply, limited maintenance support, and insufficient data on their performance in local environments (Fasoyin et al., 2021; Okon et al., 2025). Moreover, many published feeder designs demonstrate good results in controlled or temperate environments, but few have been adapted or validated for Nigerian aquaculture conditions — such as high temperatures, variable power supply, and local fish species with peculiar feeding behaviors. This study therefore focuses on designing and fabricating a solar-powered, automatic fish feeder using locally sourced materials and evaluating its performance under realistic pond conditions, with benchmarking against manual feeding methods. 2. MATERIALS AND METHODS 2.1. Materials The system comprises a screw conveyor driven by a 12V DC motor powered by a rechargeable battery, which is sustained by photovoltaic cells. The integration of solar energy was guided by prior research demonstrating the viability of renewable energy sources in powering aquaculture devices (Rahman et al., 2022). The hopper was designed to hold up to 6 kg of feed, with dispensing tested across pellet sizes of 4–6 mm. The electrical system included motor control circuitry with PWM regulation to allow adjustable feeding rates. Performance evaluation involved feed accuracy, power consumption, and operational stability, tested under both laboratory and pond conditions. The device was fabricated using PVC pipes and Teflon for their lightweight, corrosion resistance, and durability. The primary components include: a. Hopper (feed storage) b. Screw conveyor (feed transportation mechanism) c. 12V DC motor (power source) d. Solar panel & battery (energy source) e. Relay, timer, and charge controller (automation control) (Kumar et al., 2023) The materials used are shown in the exploded view in Figure 1, while the isometric view of the machine is shown in Figure 2. 2.2. Methods The fabrication and assembly process began with machining the screw conveyor from Teflon on a lathe to achieve the required geometry and smooth finish. Next, the PVC pipes were carefully cut to specified dimensions, after which bearings were installed at both ends of the shaft to ensure proper rotational support. The motor, conveyor, and hopper were then assembled in their designated positions, followed by connecting the relay, timer, solar panel, and charge controller to the battery to establish the power system. The motor 477 G.S. Linus et al. / Nigerian Research Journal of Engineering and Environmental Sciences 10(2) 2025 pp. 475-485 was subsequently wired to the relay, and all electrical and mechanical components were securely fastened. Finally, the hopper and pipes were connected and screwed together to complete the system assembly. Figure 1: Part-by-part view of the automatic fish feeder Figure 2: Isometric view of the automatic fish feeder 2.3. Design Procedure Figure 3 shows the steps taken to design the automatic fish feeder. A decision matrix was conducted using five different categories during the process of brainstorming such as performance, reliability, cost, ease of manufacture, size and weight, and maintainability. Sketches and paper models were done, followed by material selection, cost analysis, design of the various elements and fabrication, after which the device was tested using different sizes of feed ranging from 4mm to 6mm at varying time intervals. 2.4. Design Considerations The feeder was designed for efficiency, ease of maintenance, and adaptability to different environments. Key considerations include: 1) User-friendly operation with minimal adjustments. 2) Low power consumption for prolonged use. 478 G.S. Linus et al. / Nigerian Research Journal of Engineering and Environmental Sciences 10(2) 2025 pp. 475-485 3) Cost-effectiveness using affordable and locally available materials. 4) High efficiency and durability with minimal wear and tears. Figure 3: Procedure taken during design 2.4.1. Hopper and barrel capacity The hopper, which functions as the storage chamber for the feed material, is constructed from a combination of a cylindrical section and a frustum. Its total volume was obtained by summing the volumes of these two geometric shapes, as expressed in Equation (1). Volume of hopper (Vh) = volume of cylinder + volume of frustum Vh= πR2H + 1 3πh(R2+ r2+Rr) (1) Where, R = Radius of the cylinder (i.e., larger radius (mm), H = Height of cylinder (mm), r = smaller radius of frustum (mm), h = height of frustum (mm), π = constant The volume of the barrel (cylindrical section) along which the feed flows before it is dispensed is calculated using Equation (2). The barrel is assumed to be a straight cylindrical section. Volume of barrel (Vb) = πr2h (2) Where, r = radius of cylindrical housing (mm), h = length of the cylindrical housing (mm) 2.4.2. Design of shaft Putting into consideration factors such as the effect of failure, type of load, material component, cost and service conditions, the shaft is designed based on yield strength and a factor of safety of 1.5 (recommended factor of safety based on yield strength is 1.5 or 2. The shear stress was acting on the shaft material was determined using Equation (3). τmax =0.5Syt fs (3) Where; σall = allowable stress, Syt = yield strength, fs= factor of safety 2.4.2.1 Design of the shaft based on strength The bending stress acting on the shaft, due to the applied bending moment, can be determined using Equation (4) for a solid shaft (Kumar et al., 2023). The associated shear force and bending moment were calculated from Equations (5 - 7) (Nguyen et al., 2023). Figure 4 presents the distribution of shear force and bending moment along the length of the shaft. σb=32Mb πd3 (4) RA+ RB−wl = 0 (5) 479 G.S. Linus et al. / Nigerian Research Journal of Engineering and Environmental Sciences 10(2) 2025 pp. 475-485 (RB× l) − wl2 2= 0 (6) Mb=wl2 8 (7) Where, σb denotes the bending stress (Nm-2), MB represents the bending moment (N·m), d is the shaft diameter (mm), www is the weight of the shaft per unit length (kgmm-1), and l refers to the shaft length (mm). The reactions at the supports are given as RA at point A and RB at point B (N). Note: The shaft is modeled as a simply supported beam subjected to a uniformly distributed load. Figure 4: Distribution of bending moment and shear force Due to torsional moments, the torsional shear stress is given by Equation (8). The angle of twist and the polar moment of inertia, J, of a solid circular shaft are given by Equations (9) and (10), respectively (Kumar et al., 2023) τ = 16Mt πd3 (8) Angle of twist (θ) = Mtl JG (9) J = πd4 32 (10) Where. Mt is the applied torque, given in Newton-meters (Nm) d represents the diameter of the shaft, measured in meters (m). l denotes the shaft length, also expressed in meters (m). is the polar moment of inertia of the shaft cross-section (m4), G refers to the shear modulus (rigidity modulus) of the shaft material (Pa) 2.4.3. Motor power requirement and screw conveyor drive force The motor’s required power output and the screw conveyor’s driving force were determined using Equations (11 & 12), respectively (Ogunji et al. 2023). Table 1 shows the equipment specification sheet. P = Q × g(Lv. μ ± H)Ki (11) Fw=2Mw ditan(∝+B) (12) 480 G.S. Linus et al. / Nigerian Research Journal of Engineering and Environmental Sciences 10(2) 2025 pp. 475-485 Where; Q = Capacity of auger (0.8333kgs-1), Ki = Overloading coefficient ( ranges from 1.05 – 1.2 (taking mean value of 1.125)), μ = coefficient of friction for feed (2.2-2.7) (taking mean value of μ = 2.45), Lv= length of auger shaft, H = Perpendicular height (m), g = acceleration due to gravity, Mw = Angular momentum, di = diameter of screw where the bulk of materials move (0.08m), ∝ = pitch angle (23°) B = Frictional angle for the entire screw (°).s Table 1: Equipment specification sheet Dimensions (mm) Hopper Barrel/Cylindrical housing Shaft Cylinder Frustum Radius 50 Length 150 Radius 130 Radius 37.5 Length 500 Radius 15 Height 130 Height 110 Volume of Hopper: 9572367.37mm3 Volume 3926990mm3 Dry fish feed 16g occupies 24.743mm3 Moisture content of 12% wet basis Shaft design parameters Motor Screw conveyor Factor of safety 1.5 P 10W Frictional angle 24.227° τmax 266.7N/mm2 Angular momentum 1.224Nm Reaction (RA= RB= 1.508N) N 14rpm Angular force 0.0649N Bending moment 0.056Nm Driving force 16.392N σb 21335.14Nm−2 Torque 1.4139−6Nm G 79.3Nm-2 θ 0.003363rad J 7.952× 10−8m4 Other components Battery voltage 12v Bearing φ30mm Wooden base 650mm × 210mm × 20mm Solar panel 670mm × 630mm × 30mm Efficiency 99% 2.5. Mode of Operation The automatic fish feeder is powered by means of a 12V DC battery, which is recharged using solar energy obtained by means of a photovoltaic cell. On full charge, the battery can last for a period of 72 hours. The battery then powers an electric motor to which the shaft of the screw conveyor is connected. When the electric motor rotates, it drives the screw conveyor, which in turn transports and releases the feed into the fish tank through an outlet. The dispensing process occurs at operator-defined intervals, regulated by the timer. The device is illustrated in Figure 5; (a) and (b). 481 G.S. Linus et al. / Nigerian Research Journal of Engineering and Environmental Sciences 10(2) 2025 pp. 475-485 (a) (b) Figure 5: (a) The automatic fish feeder (b) Photovoltaic cell (solar panel) used with the machine 2.6. Performance Evaluation Metrics The efficiency of the feeder, feed accuracy, and operating stability were evaluated according to established performance metrics. Efficiency was determined using Equations (13), while feed accuracy and operating stability were computed using Equations (14) and (15), respectively. Efficiency =Quantity of discharge Quantity of feed input into the feeder ×100 (13) Feed Accuracy = (1 − 𝑀𝑡−𝑀𝑎 𝑀𝑡) (14) Operating Stability =Number of successful runs Total runs ×100 (15) Where, 𝑀𝑡= Target mass and 𝑀𝑎= Actual mass dispensed 3. RESULTS AND DISCUSSION The automatic fish feeder was powered by a 12 V DC battery charged via photovoltaic cells. On a full charge, the battery sustained continuous operation for up to 72 hours. Performance testing was conducted using fish feed sizes between 4 mm and 6 mm, with the hopper fully loaded to its 6 kg capacity. The system dispensed 5.93 kg of feed, achieving an efficiency of 99%. Feed loss was minimized due to the improved screw conveyor design, and the device operated reliably across different feeding intervals. Figures 6, 7, and 8 represent the quantity of feed discharged over time for different pellet sizes, while Figure 9 shows the average discharge rate across all sizes. Results indicate that the quantity of feed dispensed increased with time and speed of operation. However, at higher speeds, there was a tendency for pellet crushing, making moderate speeds preferable. Additionally, larger feed sizes (6 mm) resulted in slightly lower discharge rates compared to smaller sizes, consistent with flow resistance in the screw conveyor system (Nguyen et al., 2023). In addition to measuring dispensing efficiency, the results were benchmarked against manual feeding practices under realistic pond conditions. The automatic feeder achieved greater accuracy in delivering the intended feed quantity, thereby minimizing wastage and ensuring consistent feeding schedules. Manual feeding, by contrast, showed variability due to human error and irregular timing. Power consumption tests further confirmed that the solar-battery system sustained reliable operation with lower energy demand compared to estimates for manual labor inputs. The feeder also demonstrated greater 482 G.S. Linus et al. / Nigerian Research Journal of Engineering and Environmental Sciences 10(2) 2025 pp. 475-485 operating stability, functioning consistently across different feed sizes and intervals, whereas manual feeding often resulted in uneven distribution. Table 2 summarizes the comparative performance of the automatic feeder and manual feeding. The results clearly highlight the operational advantages of automation in aquaculture, particularly in reducing labor, conserving feed, and improving growth conditions. Figure 6: Graph of quantity of feed discharged against time for 4mm feed size Figure 7: Graph of quantity of feed discharged against time for 5mm feed size 483 G.S. Linus et al. / Nigerian Research Journal of Engineering and Environmental Sciences 10(2) 2025 pp. 475-485 Figure 8: Graph of quantity of feed discharged against time for 6mm feed size Figure 9: Graph of average quantity of feed discharged against time for 4mm-6mm feed sizes Table 2: Performance comparison of automatic and manual feeding methods Performance Metric Automatic Feeder Results Manual Feeding Results Observations Feed Accuracy (%) 98–99% (consistent across 4–6 mm) 85–90% (varies with operator) Automatic feeder more precise and consistent Power Consumption ~10 W (solar battery sustained 72 h) Human labor input, no automation data Automatic feeder requires minimal power, labor intensive otherwise Operating Stability Stable across intervals and sizes Inconsistent timing and distribution Automatic system ensured reliable scheduling