Author: Reaz Wasifur Rahman

This is an audio amplifier that takes a small AC input signal from 3.5mm Audio Jack and powers up a 8 ohm speaker through a series of signal and power amplifier. The design includes two signal amplifier circuit, followed by a power amplifier. It operates on a 12V dc source. Each amplifier is simulated in Multisim- all the DC operating points and transient analysis is performed by Multisim and confirmed by manual calculations using SparkView and a four channel Oscilloscope.

PROJECT DESCRIPTION

This project investigates the fusion of hydro-kinetic energy generated by a series of in-pipe water turbines and electric energy gained from a series of solar panels. This combined energy source is applied to break down rainwater into hydrogen and oxygen form. This micro energy unit could be a potential resolution to the energy crisis in developing countries by producing energy from natural elements such as rainfall and/or sunlight.  In my research, I have studied and tested my hypotheses correlating the production of hydrogen and oxygen with different varying constructional components. In my model, I used a water turbine setup at the bottom of rain gutters that had a direct access to the rainwater collected on the rooftop of a building. The kinetic energy generated by the vertical flow of rainwater through the pipe causes the water turbine to rotate which in turn generates electrical energy. This hydrokinetic energy source is combined with a series of solar panels to produce enough electrical power to accomplish the hydrolysis reaction.  In my laboratory experiments, my micro-model consisted of a 3 V solar panel, a 3 V motor with the water turbine, and a 3 V hydrogen fuel cell.

Image: A complete simulation of the project designed in Autodesk Inventor 2015

Image: A motor attached to water turbine (designed via Autodesk Inventor 2015)

Image: Prototype Prepared for Engineering Research Competitions

Image: A solar panel designed in Autodesk Inventor Professional 2015

Image: In-pipe water turbine designed in Autodesk Inventor 2015

Image: A prototype of a water turbine made in Brooklyn Tech Robotics Workshop

This project was born out of necessity. My Bluetooth speaker stopped working all on a sudden. I opened up the speaker, found the PCB and noticed that the 5V DC jack is broken and as a result, it’s not charging anymore.

I spent some time studying the PCB, tracing the PCB routes and realized that the DC jack was designed to get power from a continuous supply and it charges a 3.7V(1200 mAh) Li-Po battery. The battery is then connected to all the components on the printed circuit board. I decided to remove the battery, extend the power wires from the speaker and directly solder them to a 5V continuous DC supply. Although the speaker lost its portability due to this redesigned model of the power circuit, I was able to fix it without buying any additional component. Plus, my use of the speaker is almost always stationary.

Image: exposed PCB after opening the speaker