What better way to introduce absolute beginners to the enchanting world of electronics than to show them some finished products and projects designed and fabricated by students like them! The journey was embarked by inaugurating the event using the Inauguration Lamp-a patented project by CEDT, NSIT. Participants were briefed about its working and its commercial applications and feasibility. Following this, a recorded video of Prof. Dhananjay V. Gadre was played in which he welcomed all and emphasized on the DIY concept. Next in line, a series of projects were demonstrated by senior mentor, Nikhilesh Prasannakumar along with the underlying principles being discussed. This activity captivated the audience and awe-inspired them. Post project demonstration, a variety of experiments were performed which illustrated the use of speaker as a microphone, application of motor as a generator, use of LED as a sensor and working of a peltier module.
Nikhilesh Prasannakumar demonstrating projects and experiments
After a break of 15 minutes, the session resumed and was headed by Riddhi Luthra and Apoorva Mahajan( 3rd Year, ECE, NSIT) in which participants got acquainted with Printed Circuit Boards (PCBs) and got a glimpse of what exactly they would achieve at the culmination of the two-day long workshop. The discussion began with the idea of building electronic circuits on a simple breadboard. Those who were new to it, were introduced to this most fundamental electronic circuit prototyping board. The temporary and unreliable connections, the heavy weight of the breadboard, its non-usability in portable projects paved way for the need of PCBs. Printed Circuit Boards along with being durable, light in weight, ensure firm and stable connections and can be made custom-sized. The participants were informed about the PCB design software: EAGLE CAD used to design layouts.
After an insight into the world of PCBs, the participants were informed about the intricacies involved in fabricating a PCB using the most convenient home-made method known as Toner- Transfer Method. Starting from the sanding of the 1.6 mm thick copper clad boards (with 36 microns of copper) to remove the oxide layer, the various processes involved in the PCB fabrication were explained in detail. An illustrative power point presentation aided in visualising the processes better.
The Toner-Transfer Method
The PCBs are made using copper clad boards which are essentially copper sheets laminated onto non- conductive substrates (Epoxy resin, FR4). The Toner-Transfer method involves the transfer of ink/toner from the print of the circuit on a glossy paper onto the copper clads. This transfer is done using an ironing press by applying uniform heat and pressure. After that, the paper is removed gently with the help of water. The excess copper (not underneath the ink) is then etched off the board using FeCl3 solution. After that the ink is removed using a scrub and the exposed copper tracks are prevented from oxidation using an acrylic film spray. The vias are drilled and components are soldered on the board. The flowchart of the various steps involved is shown below.
The students were divided into two groups and while one group departed for lunch, the other one commenced with the fabrication process. After an hour, the groups switched their activities.
Participants were provided with a copper clad and board layout print each and a team of about 30 mentors assisted them at each stage of the process. The key points to be kept in mind while performing each step and the precautions to be taken were discussed. Also, the consequences of any step being carried out wrongly were informed. The boards were verified by the mentors before the participants proceeded to the next stage.
The day concluded with all the participants scrubbing their etched boards and covering them in a thin film of acrylic spray to prevent further oxidation. Few were even through with the drilling and soldering process and had got their boards tested.