BFO Metal Detector Project

 Here is an old project from 2013 when I was still an undergrad at Purdue in ECE 306. The project objective was to combine what we had gone over in the lab course of the semester. I can't remember what all sorts of things we had gone over now, but I do have a lab manual somewhere. I may include it later, but it's not terribly important what we went over specifically in the lab. The main point I'm trying to get at is that rather than the standard full semester's worth of predefined labs, the last month of the semester was dedicated to a project of our(teams of two students) choosing.

Somehow or another, my partner and I decided to make a beat frequency oscillator metal detector. There's all sorts of information about this stuff that you can search up on the internet. I remember referring to this Talking Electronics website an awful lot. I guess I should mention Charles D. Rakes and Colin Mitchell because both are somehow related to the website/information on it.

At any rate, I wanted to include some photos of the project.

The Metal Detector

The metal detector was made from a wooden dowel rod and a wooden plate. I don't remember exactly how many copper windings were made, but to make the Faraday shield I used a aluminum tape. Overall, I think the whole project cost less than $20.00.

The Circuit

 The only interesting thing worth mentioning about the circuit photo is that I used a pill bottle to wrap copper wire around which can be noticed at the top center above the breadboard. For some reason, I remember being rather proud of how symmetrical the circuit was after I had built it for the third iteration.

Here is, for the most part, the finished project on my desk at home measuring... something. Most likely the sound it would make if I had included a headphone jack.

The project on my desk

 The end results for the project were also pretty good. If I remember correctly, the detector could detect metallic objects around 2 inches (about 5 cm) under the my desk. I think I have a video of our success in the lab somewhere, but it's probably super embarrassing so I don't think I'll post it. This project was a lot of fun and I think I finished the course with an A.