[Steven Dufresne] of Rimstar.org is at it again with another very functional science experiment. This week he’s showing us how he made a large electrostatic motor, also known as a Corona Motor.
A Corona motor makes use of a cool
phenomenon called the Corona discharge, which is the ionization of a fluid
(in this case, air) surrounding a conductor that is energized. He’s done other high voltage experiments that take advantage of this, like his Ion Wind propelled Star Trek Enterprise!
The motor works by using an even number of electrodes on the motor, each electrically charged; positive, negative, positive, negative, etc.
Because each electrode is the opposite charge, they want to repel each other — but since the cylinder is electrically insulated, the charges have no where to go — instead the cylinder begins to rotate as the charges attract back and forth — when a positive charge on the insulation meets a negatively charged electrode, the charge is removed by ionization (creating the corona effect), and the cycle continues. The direction of rotation is determined by the angle of the electrodes. The motor can get going pretty fast but doesn’t have that much torque or power.
Conductive ink or paint is lots of fun. It opens up tons of possibilities for flexible and unique circuits — unfortunately, it’s pretty expensive. [Brian McEvoy] shows us how to make your own for cheap, and it works great!
He started trying to formulate his own recipe after playing with other Instructable guides and commercially available paint, and what he found is it’s really not that complex! Graphite powder, acrylic paint, and a jar with an airtight seal — seriously, it’s that simple! But, like any engineer worth their salt (he calls himself the 24 Hour Engineer), he had to do some tests to compare his formula.
In a detailed experiment he compares his formula to the commercially available Wire Glue, and two other recipes using Elmer’s Glue-All and graphite, and Titebond III with graphite. The results? Acrylic paint and graphite produce the most conductive material — and the cheapest!
For projects requiring a bit more juice, the mass production of those small rectangular lithium ion batteries for cell phones, cameras and other electronics are extremely useful — the problem is, how do you mount them, short of soldering the terminals in place? With a bit of perfboard of course!
[Jason] came up with this idea when he was trying to figure out a way to mount small lithium cells for a battery fuel gauge for another one of his projects. He found if you use good quality perfboard you can use a 90 degree male pin header to contact the terminals, and a strip of female pin header as a kind of battery stop at the other end. This allows you to very snugly squeeze the battery in place — you may need to adjust the length of the male pins though in order to fine tune the fit!
Now you can add a nice wire terminal, solder up the connections, and there you have it, an easy to make, extremely useful battery holder!
Got some empty plastic bottles in your recycling bin or cluttering up your desk? Then you’ve got a large portion of the material you need for building your own Wimshurst machine like [Thomas Kim] did. This demonstration and build video is one of the many treasures of his YouTube channel. He shows the machine in operation and then spends several real-time minutes showing how he made the heart of it using plastic bottles, the conductive brush from a laser printer, discarded CDs, and a bunch of copper wire. As a bonus, he removes the conductive material and paint from a CD with a homemade taser. As a super special bonus, there’s no EDM soundtrack to this video, just the sounds of productivity.
The Wimshurst machine is an electrostatic generator that slightly predates the Tesla coil. It works by passing a charge from one spinning disk to another disk spinning in the opposite direction. When the charge reaches the collecting comb, it is stored in Leyden jars. Finally, it gets discharged in a pretty spark and the cycle begins anew. Once you’re over shocking your friends, use your Wimshurst machine to make an electrostatic precipitator.
Until recently, watches have been entirely mechanical where each wheel, gear, and mechanism representing a milestone in our understanding of precision manufacturing and timekeeping.
Today it is nearly impossible to find watchmakers to service or repair vintage mechanical pocket and wristwatches, so we have to do it ourselves. Learn to repair vintage mechanical watches. You can do this and we’ll show you how.
GoPro cameras come out of the box with a huge set of features. Most people will be satisfied, or possibly even overwhelmed by the available options, but if you’re able to do some of these hacks, you’ll be able to expand your camera’s capabilities even more. They can, however, void your warranty, so as with most hacking, do these at your own risk.
Finally somebody has found a good use for all those old CRT computer monitors finding their way to the landfills. [Steven Dufresne] from Rimstar.org steps us through a very simple conversion of a CRT computer monitor into a high-voltage power supply. Sure you can make a few small sparks but this conversion is also useful for many science projects. [Steve] uses the monitor power supply to demonstrate powering an ionocraft in his video, a classic science experiment using high voltage.
The conversion is just as simple as you would think. You need to safely discharge the TV tube, cut the cup off the high voltage anode cable and reroute it to a mounting bracket outside the monitor. The system needs to be earth grounded so [Steve] connects up a couple of ground cables. One ground cable for the project and one for a safety discharge rod. It’s really that simple and once wired up to a science project you have 25kV volts at your disposal by simply turning on the monitor. You don’t want to produce a lot of large sparks with this conversion because it will destroy the parts inside the monitor. The 240K Ohm 2 watt resistor [Steve] added will help keep those discharges to a minimum and protect the monitor from being destroyed.
Yes this is dangerous but when you’re working with high-voltage science experiments danger is something you deal with correctly. This isn’t the safest way to get high-voltage but if you have to hack something together for a project this will get you there and [Steve] is quite cautious including warning people of the dangers and how to safely discharge your experiment and the power supply after every use. This isn’t the first high-voltage power supply that [Steve] has constructed; we featured his home-built 30kV power supply in the past, which is a more conventional way to build a HV power supply using a doubler or tripler circuit. Join us after the break to watch the video.