Posted by azelg2 on October 10, 2010 at 7:14 AM
The path to the selection of this project was not straightforward. To decide one, we brainstormed several ideas and there was also some inter-group conflict regarding the FYP choice. But there was agreement on one thing: that the project should be a challenging one and never before been done at NUST. Thinking along those lines, we seriously considered these three ideas (in chronological order) before settling on the current one:
1. Directional microphone using phased array
This is a system of microphones placed in a pattern of 1, 2, or 3 - dimensional arrays (in linearly increasing order of performance and exponentially increasing order of complexity). We intended to make a system to enable listening to a distant source of sound while rejecting other noise in its periphery. However, after extensive online literature and commercial product surveys, we decided that the result (in terms of SNR) achievable within our capability and budget would not be enough to enable sufficient voice clarity at an acceptable range.
2. Electromagnetic coil gun
After rejecting the mic array idea, we came up with another even more daring one: the electromagnetic coilgun. It is (not so closely) related to another, even more powerful system: the electromagnetic railgun
. In those, electromagnetically propelled projectiles weighing 7 kg have reached
speeds in excess of 3,000 m/s. By comparison, the most powerful sniper rifle's bullet speeds (weighing 0.05 kg) normally top out at around 1,500 m/s and normal handguns fire at ~500 m/s. Our minimum aim was a modest 100-200 m/s, still fast enough to seriously injure if it hit someone.
Before deciding on the project, we actually conducted practical feasibility experiments in the labs using 400V capacitors and motor winding coils. Though the tests were encouraging, upon further research, we calculated that to make a sufficiently powerful working gun, the costs of the required components (mostly the megajoule capacitors
and 1000V/400A SCR
's) would be too much for us, and so we had to abandon this idea as well.
This idea was originally floated by Mr. Abdul Afram
and was actually the first one we agreed upon. But before finalizing, we decided to explore the above-mentioned ideas.