Do-It-Yourself Metal Detectors (Part 6)

 (Metal detectors were first developed for military purposes.)

If you're interested in do-it-yourself metal detectors you've come to the right place. Here's more from Arizona gold miner and metal detector builder G.T. Blocker:

The Oscilloscope

"Those dreaded aliens are attacking...we can see it on our oscilloscopes!"

Metal Detectors
Gold Concentrates
Gold Pans
"In every crappy movie since the first 'B' science fiction film was made, special effects artists realized that they could make cheap and spooky, alien-looking 'squiggles' using an oscilloscope (I'm guilty too!). A generation or two or three has since watched some of these old films and more modern versions with similar themes with the same absorption and mystification."

"The aliens are coming! Why? Because our trusty o-scope says so."

Despite All the Fancy Knobs

"An oscilloscope does two things: it shows voltage vertically and frequency horizontally on a screen. It doesn't matter if you're using a laptop computer with the right software or a dedicated, $2,000+ o-scope... that's pretty much it despite all the fancy knobs. By the way, for most metal detector designs, a fast laptop with the appropriate software and add-on probes will work just fine." 

(O-scope display.)

"Watching the o-scope's wave forms can tell you a great deal about what's going on inside a metal detector. This is especially true if you're building your own coil."

Cool Machines

"Don't let the o-scope intimidate you. With just a bit of online research the mysteries of the oscilloscope will dissolve before your very eyes. O-scopes are pretty cool machines. They can make the entire build of your 'do-it-yourself' metal detector project a heck of a lot easier."

"Best keep a good lookout, however. That o-scope of yours just might find an alien transmission...(or not!)."

My Favorites

You know, as a kid growing up in the 1950s and early 1960s, I can't tell you how many of those "B" sci-fiction movies I saw in my hometown theater. Nearly every one of those flicks had an o-scope in at least one or more scenes, as G.T. correctly points out.

My favorite "B" sci-fi films of all time? The original "The Thing" (1951) and "Them" (1954). Scary visitors from outer space and atomic mutants...what kid of that era couldn't get excited about those things?

("Watch the skies...keep watching the skies." Final scene of "The Thing." )

If you liked this post, you may want to read: "Do-It-Yourself Metal Detectors (Part 5)"

(c)  Jim Rocha (J.R.)  2013

Questions? E-mail me at


  1. I bought an el-cheapo detector with a gift certificate and have enjoyed the heck out of it. just coin shooting the local baseball fields etc. I'm an electronics technician, and I know I'd be hard pressed to build one better than the el-cheapo without spending more money and a lot more time than I have to spare. Though, these last few posts have me thinking I might give it a shot. Good posts J.R. & G.T., thanks.

    BTW; "The day the Earth stood still" is one of my favorites and I still love "The Twilight Zone".....good stuff.


  2. When it comes to detectors I guess what works! Yep, "The Day the Earth Stood Still" is one of the best of that era and genre...but I don't consider it a "B" quality flick. Has great actors, story, and production values. Thanks for commenting Bo, J.R.


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