The Grid Dip Meter: Forgotten Instrument

It used to be a major rite of passage for a hardware hacker to acquire an oscilloscope. Until recently, new instruments were rarely in normal people’s budgets, so you probably made do with a used scope. Now, there are lots of inexpensive options, especially if you include low-end PC scopes and “scope meters.” Digital meters are also now inexpensive (often free at some major stores), along with signal generators, frequency counters, and even logic analyzers.

But there is one piece of test equipment you don’t see as often as you used to and its a shame, because it is a very versatile piece of kit. Admittedly, if you aren’t doing wireless work, it might not be high on your wish list, but if you do anything with RF, it is not only a versatile tool, but a good value, too. What’s it called? That depends. Historically, they went by the name “Grid Dip Oscillator” or GDO. Sometimes you’d hear it called a “Grid Dip Meter” instead. However, modern versions don’t have tubes (and, thus, no grid) so sometimes you hear them now called dip meters or maybe just dippers.

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3D Printed Desklamp Follows Tesla For Cordlessness

If not for [Nikola Tesla], we’d be pretty behind when it comes to electricity. So to pay homage to one of the greatest inventors, [David Choi] decided to make his very own wireless Tesla Desk Lamp!

As expected, [David’s] a big fan of [Nikola], and has always been inspired by his life and experiments — in particular he loves wireless power. Ever since he saw a Tesla Coil light up a bulb from a distance he was smitten. He even named his cat Tesla.

The funny thing is, [David] actually failed physics in high school, but a few years later decided to pursue it as a career while attending Wesleyan University. It didn’t stop when he graduated, he also studied electronic design in his spare time — which is where he learned about resonance.

Wanting to apply what he had learned he has created a very unique wireless desk lamp. Don’t let the pictures fool you; it’s actually 3D printed! It uses one of those retro “vintage” light bulbs, which has it’s power transmitted to it wirelessly by a 6.5MHz signal. It was relatively easy to get the wireless part right, because once he had calculated the number of coils he needed, all he had to do was 3D model the track for the copper to go in.

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