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This paper presents a low-cost printed circuit board (PCB) design technique and processes using ferric chloride (FeCl3) solution on a metal plate for a design topology. The PCB design makes a laboratory prototype easier by reducing the work piece size, eliminating the ambiguous connecting wires and breadboards circuit errors. This is done by manual etching of the designed metal plate via immersion in ferric chloride solutions for a given time interval 0-15mins. With easy steps, it is described on how to make a conventional single-sided printed circuit board with low-cost, time savings and reduced energy from debugging. The simulation and results of the printed circuit is designed and verified in the Multisim software version 14.0 and LeCroy WJ35A oscilloscope respectively. [ABSTRACT FROM AUTHOR]

Splitting of a dc voltage source with two capacitors has been the approach in generating 5-level output voltage with single- and three-phase full-bridge circuits and added bidirectional switch. Associated with this configuration is the problem of voltage imbalance between the splitting capacitors. In addition, the inverter output voltage magnitude is obviously limited to the value of the split input voltage source. Presented in this paper is a unit topology for single-phase 5-level multilevel inverter, MLI. It simply consists of a full-bridge circuit, a capacitor, charge-discharge unit and a dc source. The charge-discharge unit with the capacitor is the interface between the fullbridge and the dc source. The proposed unit cell can generate a 5-level output voltage waveform whose peak value is twice the input voltage value. For higher output voltage level, a cascaded structure of the developed unit cell is presented. Comparing the proposed inverter with CHB inverter and some recent developed MLI topologies, it is found that the proposed inverter configuration generates higher output voltage value, at reduced component-count, than other topologies, for a specified number of dc input voltages. For two cascaded modules, simulation and experimental verifications are carried out on the proposed inverter topology for an R-L load. [ABSTRACT FROM AUTHOR]

This research paper expounds microcontroller based binaural digital hearing aids for hearing-impaired people by making use of ATmega328 microcontroller and other circuitries to process the audio signal input by either increasing or reducing the gain level of input audio signal, filter background noise, frequencies compression, save battery power and minimize circuit by making use of the internal ADC of the microcontroller and two PMW pins of the microcontroller as DAC. Hearing impairment among the youths and adults nowadays are in the increase, due wrong use of phones of which every minute of the day someone's earphone is on listening to one type of music or the other. In other to solve the problem created so to say this research work was conceived and given birth to. The different stages of digital hearing aid are designed and then simulated first in Proteus software which then was implemented using PCB-board. The main components of this system were the audio input unit which consists of the microphone and its pre-amplifier, the microcontroller (ATmega328) which consists of the ADC, the DAC and the audio signal processing, the filter stage and control codes (frequencies compression codes, power saver codes, acoustic feedback control codes, signal level control and adaptive adjustment codes etc.), the power amplifier and volume control unit and then the earphones (output). The control codes were written in C language while Ardinuo Uno compiler was used to write the codes into ATmega328. The prototype has an overall system gain of 27dB and the power output of 32.5mW. The prototype was tested with a patient that has a hearing impairment and the patient was satisfactory with the device. [ABSTRACT FROM AUTHOR]

This paper elucidates a radio frequency (RF) based transmission and reception system used to remotely monitor and control the water Level of an overhead tank placed up to 100 meters away from the pump and controller. It uses two Radio Frequency transceivers along with a controller each installed at the overhead tank and the sump (reservoir). It is completely automated with the help of a PIC 16F877A micro controller which receives signals from the transmitter, interprets and effectively communicates the status of the water overhead tank and water pump mode to the user or operator via an integrated LCD display. Similarly, the control unit of the prototype performs automatic switching control of on and off on a single phase centrifugal water pump, 220volts, 0.5hp motor via a motor driver circuit (relay). It also incorporates a buzzer that beeps briefly when water level hits 100%, thus causing the pump to be switched off but when water level drops below 25%, the pump is then switched on. [ABSTRACT FROM AUTHOR]

This paper elucidates a single axis solar tracker system that automatically searches the optimum PV panel position with respect to the sun by means of a DC motor controlled by an intelligent drive unit that receives input signals from light dependent sensors. A prototype of the mechanical maximum power point tracker (MMPPT) was implemented with a motor size of 48W. The power supply unit consists of only supply source which is the AC mains. The sensor unit consists of six sensors. While five are fixed and adjacently aligned at 36° to each other (tracking sensors), the sixth one is movable as it is attached to the surface of the PV panel (feedback sensor). The control unit is divided into two parts: A priority voltage selector and a movement controller. The priority voltage selector comprises of cascaded comparators which compares the five voltage outputs from the sensors and selects the highest voltage (priority voltage). The movement controller compares the feedback voltage with the priority voltage and logically decides whether to move the motor clockwise or anti-clockwise. The solar panel is allowed to move from east to west and back forth with a maximum allowable angle of 180°. its movement is in only one axis. The prototype built carries the panel from eastward to westward tracking the sun movement from sun rise to sun set and then reset to face eastward as darkness sets in. The results obtained from the prototype MMPPT were used to compare with the results obtained from fixed panel under the same environmental conditions and at the same time interval of 30 minutes using the same type of PV panel. The result from MMPPT has a gain of 5.77% over its counterpart which is fixed panel. [ABSTRACT FROM AUTHOR]