This is actually a somewhat old project of mine. I did it in the 12th std. as my final exam project.
I basically wanted to do something different. Most friends were just buying readymade kits and just soldering them together. Well I was no different, even I did the same! I got a Metal Detector kit for Rs. 80 ($2).
All was fine. I was feeling I had a unique project but as the submission date neared, I came to know that there were atleast 5 other people using the same kit. All the time I had been looking for something better to make and as I had been unable to think of something I had to buy this kit.
Finally I thought harder. Then in that week we had a practical where we were taught the use of a decade counter, a circuit that would count upto 9 with clock pulses at the input. It used an IC7490 as a counter and an IC 7447 as a driver for the 7-segment display we were using…
Now I thought that my metal detector gives high-low signals each time so I can get a counter to count them. Further getting two of these counters in series I can get it to count upto 99! So then thats what you have here in this video, its counting coins. Cool?
Video credits: Avinash Bangera — A friend of mine from 11th std.
Originally published at paramaggarwal.com.