Department of Electronic Engineering Research Projects 2007-2009

Design of a humidity controller for an incubator

¹S. Mangozho, ²V Kuno

¹Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare
2Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare; vkuno@hit.ac.zw

A humidity controller was designed for a child incubator system. This included a microcontroller, a variable impedance sensing circuit and a zero crossing detector circuit. The humidity sensing circuit and the zero crossing circuit were provided with an AC line voltage and both had outputs which were provided by the microcontroller. The humidity controller also included a semi conductor switch circuit which switches AC line voltages to an external electrical device, such as the dehumidifier at the zero crossing.

Design of a transformer protection system.

¹B Manuel, ²V. Kuno

¹Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare
²Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare; vkuno@hit.ac.zw

A transformer protection system was designed for protection of transformers against bursting as it runs out of transformer oil. This was necessitated by increased transformer oil drain by thieves. The systems use a PIC 16F84 microcontroller for monitoring the transformer temperature and oil depth. From this it decides using the program when to give a warning signal and then to finally switch off the transformer.

A microcontroller based child incubator control system.

¹T.Zitsanza, ²T.Pondani

¹Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare
²Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare; tpondani@hit.ac.zw

The purpose of the project was to replace the analogue hardwired child incubator control system with an intelligent control system which uses a PIC 16f877. The control system was able to control temperature, and humidity. This was done for Parirenyatwa Group of Hospitals.

An Agrimeter.

¹Artmore Nhara, ²S. Magidi

¹Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare
²Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare; smagidi@hit.ac.zw

An Agri meter was designed and prototyped. This is an instrument which is able to measure agricultural parameters. The one designed was able to measure soil temperature, PH and Humidity. Being portable it proved useful for modern day farmers and that it powered by 12 V battery.

Load Shedding Controller

¹B Manuel, ²S. Magidi, ³V. Kuno

¹Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare
²Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare; smagidi@hit.ac.zw
³Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare; svkuno@hit.ac.zw

A load shedding controller was designed. The load shedding affect individual households depending on their usage of electricity as opposed to the present system in which the whole area is shaded. Thus electricity can be cut for geyser supplies whilst it’s not for lights. Hence electricity can be supplied for lights and other low power devise such as computers and televisions, whilst the other households are only able to use heavy current devices such as cookers. The heart of the system is a PIC 16f877 microcontroller which get its inputs from the ZPC database and decide which individual household are to be shaded. This is done automatically.

Design and Implementation of a microcontroller based traffic light for a complex system

¹T. Zitsanza, ²S. Magidi

¹Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare
²Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare; smagidi@hit.ac.zw

Traffic flow is by nature a dynamic process, rendering static, fixed time signaling system inadequate. The main objective of the project was to design, simulate and implement a suitable algorithm for an intelligent traffic light controller. The system developed was able to sense the presence of vehicles within a range by setting appropriate duration for the traffic light signal to illuminate. The system can help solve the problem of traffic congestion. Controllers are interconnected with communication network, passing to each other traffic load information and getting synchronized. As a result, the duration of relative phases of each traffic cycles dynamic change. The simulation of the traffic signal system was done using MPLAB software. The new timing system that was implemented promises an improvement in the current traffic system and is feasible, affordable and readily implemented especially during peak hours

Electrosurgical Unit

¹A. Nhara ; ²S.Magidi

¹Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare
²Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare; smagidi@hit.ac.zw

An electrosurgical unit was designed and prototyped. This is a unit that replaces the surgical razor blades for the operation of patients. The unit stops excessive bleeding at the same time making effective operation to patients. The surgical cutting edge of the machine is electrically induced. It uses high frequency and high voltage and uses a spark generator which comprises a radio frequency power inverter and a transformer. When the machine is operating, the patient is sandwiched between two alternating potentials namely the pencil and the neutral plate. The patient lies on a neutral plate, whilst the operator performs the incision using the pencil. It uses the thermal effect. As water heats up when high frequency current pass through the cells, an opening is formed since the cell is in contact with the pencil burst or break up as water boil and expand.

Stepper Motor Control using PIC 16 F84

¹S. Mangozho; ²T. Pondani

¹Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare
²Department of Electronics Engineering, Harare Institute of Technology, Box Be 277, Belvedere, Harare; tpondani@hit.ac.zw

Micro stepping improves the efficiency of the system since the current in the motor windings is manipulated in a controlled manner rather than being turned ON and OFF abruptly. A micro stepping technique known as high torque alternatively varies the current in the windings of the stepping motor. High stepping is achieved by pulse width modulating one winding using the ECCP module and the duty cycle of the module is varied according to the cosine lookup table.