[Eric] has an Atwater Kent 55C AM radio from the early 1900’s. He’s been trying to restore the radio to proper working condition. His most recent pain has been with the rectifier tube. The tube is supposed to have a complete vacuum inside, but that’s not the case here. When the tube is powered up, it glows a beautiful violet color. It may look pretty, but that’s indicative that gas has leaked into the tube. It needed to be replaced.
[Eric] had a tube that would serve as a good replacement, but it’s plug didn’t fit the socket properly. He was going to have to use this old broken tube to make an adapter. Rather than just tearing the old tube apart, he decided to have some fun with it first. He hooked it up to a variac, an ammeter, and a volt meter. Then he slowly increased the voltage to see what would happen. The result was visually stunning.
The tube starts out with the same violet/blue glowing [Eric] experienced previously. As the voltage increases, it gets more and more intense. Eventually we start to see some green colors mixing in with the violets. [Eric’s] reaction to this unexpected result is priceless. As the tube gets increasingly hot, the anode starts glowing an orange-red color. Finally, the filament starts to crackle like a sparkler before the tube just gives up and completely fails.
After the light show, [Eric] moves on to replacing the tube. He begins by tapping on the old tube’s socket with the end of a screwdriver. After much tapping, the glass starts to come lose from the socket. After a bit of wiggling and twisting the tube finally came free from the socket. [Eric] luckily had an unused octal socket that fit perfectly inside of the old socket. All he needed to do to build his adapter was to connect the four pins from the old adapter to the proper pins on the octal socket. Piece of cake.
…Or so [Eric] thought. After testing some new tubes with a tube tester, he realized he had soldered all four pins incorrectly. On top of that, he had super glued the adapter together. He eventually got the two pieces apart. This time he removed all of the unused pins from the octal socket so he wouldn’t get it wrong. Another run on the tube tester confirmed that everything looked good. After plugging the tube into the radio, it worked just as expected
If you need fabrication rather than repair, we’ve got you covered there as well. Check out [Charles Alexanian’s] process for making new vacuum tubes in his garage. Now if you just have too darn many of them around, you can always decorate your pad with ’em.
Continue reading “Vacuum Tube Repair After a Spectacular Failure”
We’ve seen pick and place tools in the form of tweezers, mechanical pencils adapted to aquarium pumps, but never as a 3D printed tool optimized for standard blunt-nose needles in a comfortable, ergonomic shape.
[Zapta] created this 3D printed SMD hand picker to populate a few boards. The tool is mostly 3D printed parts that come together for an airtight enclosure. The needles are the standard eBay affair, with the smallest he could find easily lifting 0402 and 0603 components from their tape reel. There’s also the option to switch over to larger needles for bigger components.
There are files available for two versions of this vacuum picker – one with a hole in the handle for those of us who would rather connect this thing directly to a modified aquarium pump, and one for the geniuses among us who use a foot pedal and pneumatic valve to release the tiny part. Other than the pump, the only a few bits of tubing are required to turn this bit of 3D printed plastic into a useful tool.
Experimentation with the unusual nature of things in the world is awesome… especially when the result is smokey glowing plasma. For this relatively simple project, [Peter Zotov] uses the purchase of his new vacuum pump as an excuse to build a mini vacuum chamber and demonstrate the effect his mosfet-based Gouriet-Clapp capacitive three-point oscillator has on it.
In this case, the illumination is caused due to the high-frequency electromagnetic field produced by the Gouriet-Clapp oscillator. [Peter] outlines a build for one of these, consisting of two different wound coils made from coated wire, some capacitors, a mosfet, potentiometer, and heat sink. When the oscillator is placed next to a gas discharge tube, it causes the space to emit light proportionate to the pressure conditions inside.
For his air tight and nearly air free enclosure, [Peter] uses a small glass jar with a latex glove as the fitting between it and a custom cut acrylic flange. With everything sandwiched snugly together, the vacuum hose inserted through the center of the flange should do its job in removing the air to less than 100 Pa. At this point, when the jar is placed next to the oscillator, it will work its physical magic…
[Peter] has his list of materials and schematics used for this project on his blog if you’re interested in taking a look at them yourself. Admittedly, it’d be helpful to hear a physicist chime in to explain with a bit more clarity how this trick is taking place and whether or not there are any risks involved. In any case, it’s quite the interesting experiment.
[Ben Krasnow] is tackling the curious Crookes Radiometer on his Applied Science YouTube channel. The Crookes Radiometer, a staple of museum gift shops everywhere, is a rather simple device. A rotor with black and white vanes rotates on the head of a needle. The entire assembly is inside a glass envelope. The area inside the glass is not at a hard vacuum, nor is it filled with some strange gas. The radiometer only works when there is a partial vacuum inside.
The radiometer’s method of operation was long misunderstood. Sir William Crookes and James Clerk Maxwell both believed that the vanes moved due to the pressure of the photons hitting the vanes. If that were true though, the radiometer would spin in the opposite direction it normally does when held near a light source. It was eventually discovered that the system is a thermodynamic one. [Ben] proves this by cooling down the radiometer’s glass with a can of freeze spray. The radiometer immediately begins spinning backwards, with no light source present.
From there [Ben] mounts the rotor of a radiometer inside his vacuum chamber, which many will recognize as the chamber from his DIY electron microscope. As expected, the vanes don’t spin at a hard vacuum. In fact, [Ben] find the vanes spin fastest when the pressure is about 7 mTorr.
Continue reading “[Ben Krasnow] Shows us How a Crookes Radiometer Works”
If you’re building a pick and place machine, or even just a vacuum pen, you’ll need some way to pick up tiny part. This means something that sucks, aquarium tubing, and everything that goes with that. A few months ago, [Wayne] found an interesting device called a Micro Blower that will blow small amounts of air from a small, lightweight device. A few modifications later, and he had a piezoelectric vacuum pump for picking up tiny parts.
The Micro Blower [Wayne] found is available on Mouser for about $45, but this device blows. To turn it into something that sucks, he would need to find a way to block up the input side of the pump so it could draw a vacuum. Eventually settling on mounting the blower inside a stack of foam board, [Wanye] glued on a 20 gauge needle and was able to suck up 0603 SMD parts.
The new piezoelectric sucker is extremely light, and the power draw is very reasonable: 18V and 20mA. This would be a great device to mount to a certain pick and place machine without having to run vacuum lines through the mechanics of a motion platform. Video below.
Continue reading “Piezo Vacuum Pump for Lightweight Pick and Place”
[Niklas] told us about his newest art project that he is calling a Pneumatic Sponge Ball Accelerator. This isn’t a home workshop type of project, it is a full fledged art exhibit displayed at the Tschumi Pavilion in Groningen / The Netherlands. One-thousand black sponge balls move from a big glass ball-reservoir bubble to another via a 150 meter long track of clear plastic tubing. The balls move up to an impressive 4 meters a second. Admirers of the installation can operate the machine and its airflow from outside the pavilion by pressing their hand up to a touch sensor installed on the wall of the exhibit.
All of the ball movement is powered by an ordinary home vacuum. Since it would be a short display if all the balls traveled in one direction, ending up in just one of the glass bubbles, [Niklas] came up with a simple yet functional valve that reverses the flow of air in the tube. This is done by a rotatable disk with two holes in it. Depending on its position, it connects one of the two bubble to the vacuum, leaving the other vented to outside atmosphere. Since the vacuum side of the path is low pressure and the ambient atmosphere is relative high pressure, the air travels towards the vacuum bringing the foam balls with it. No balls get sucked into the vacuum because the outlet tube is at the top of each bubble.
Find two videos after the break, they are well worth watching.
Continue reading “Another Ball Sucking Machine Leaves You Wanting More”
The best career choice anyone could ever make – aside from the richest astronaut to ever win the Super Bowl – is the designer of the kinetic art installations found in science centers that roll billiard balls along tracks, around loops, and through conveyors in a perpetual display of physics and mechanics. [Niklas Roy] isn’t quite at that level yet, but he has come up with a new twist on an old idea: a machine that literally sucks balls from a ball pit into transparent tubes, sending them whizzing around the installation space.
The installation consists of eighty meters of plastic tubing suspended in the staircase of Potocki Palace in Kraków. Electronically, the installation is extremely simple; a PIR sensor turns on a vacuum cleaner whenever someone is in the ball pit. This sucks balls up through a hose, around the space, and into a bin suspended over the pit. Pull a lever, and the balls stored in the bin are dispensed onto the person vacuuming up thousands of balls below.
Image source, with video below.
Continue reading “This Machine Sucks Balls”