[Ben Krasnow] Shows us How a Crookes Radiometer Works

[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.

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Piezo Vacuum Pump for Lightweight Pick and Place

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.

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Another Ball Sucking Machine Leaves You Wanting More

Pneumatic Sponge Ball Accelerator

[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.

Pneumatic Sponge Ball Accelerator

 

Find two videos after the break, they are well worth watching.

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This Machine Sucks Balls

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.

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Solder Sucker Meets Industrial Vacuum Pump

sucker

[borgartank] is starting a hackerspace with a few guys, and being the resident electronics guru, the task of setting up a half-decent electronics lab fell on his shoulders. They already have a few soldering stations, but [borgar] is addicted to the awesome vacuum desolderers he has at his job. Luckily, [bogar]’s employer is keen to donate one of these vacuum desolderers, a very old model that has been sitting in a junk pile since before he arrived. The pump was shot, but no matter; it’s nothing a few modifications can’t fix.

The vacuum pump in the old desoldering station was completely broken, and word around the workplace is the old unit didn’t work quite well when it was new. After finding a 350 Watt vacuum pump – again, in the company junk pile – [bogar] hooked it up to the old soldering station. Everything worked like a charm.

After bolting the new and outrageously large pump to the back of the desoldering station, [bogar] wired up a relay to turn on the pump with the station’s 24V line. Everything worked as planned, netting the new hackerspace a 18 kg soldering station.

A pick and place tool from medical equipment

neb

A vacuum tool is an invaluable tool if you’re working with tiny SMD parts, and even with tweezers you might have a hard time placing these nearly invisible components on their pads for soldering. One tool that’s really great for these parts is a vacuum pen, usually made from an old aquarium air pump. [Jon] may have found a much more suitable piece of equipment to scavenge for a vacuum pen build – a nebulizer.

Nebulizers provide asthmatics with low pressure, low volume air to atomize medication for inhalation. Inside the nebulizer is a small diaphragm pump, just like the small aquarium pump teardowns we’ve seen. In just five minutes, [Jon] tore his thrift store nebulizer apart and reversed the flow of air, turning something that blows into something that sucks.

After the suction part of the build was finished, [Jon] needed a way to pick up small components. He did this by blunting a large hypodermic needle and fastening it to the end of a Bic pen with heat shrink tubing. After drilling a small hole in the pen body, he had a very nice looking SMD vacuum pump.

Vacuum pressure bazooka

This vacuum pressure cannon is a design unlike any we’ve seen before. At first look it seems to have the components you see in a potato gun. But those use a combustion process to launch the projectile. This instead uses the sudden release of a vacuum.

About three minutes into the demo video below we get a look at the “ignition” system. It’s pretty scary in that a couple of really powerful springs are pulling a collar along the barrel toward your face. This is actually meant to dislodge the plug in the back which is holding vacuum in the barrel. The pressure difference causes a sudden inrush of air which shoots the 1.5 inch projectile out the front of the bazooka.

[Mr. Teslonian] built his own hand powered vacuum pump for loading the weapon. This was done with a pair of PVC pipes that fit inside of one another, and a plunger made from wood and leather. The PVC and wood projectile seals in the barrel using a skirt made from duct tape. After breech loading the projectile and plugging the back of the barrel, he layers aluminum foil over the business end and pumps up a high vacuum. His test firing is not from the shoulder, and he only gets one shot because the slug hit the target so hard it was destroyed. This thing really needs to be vehicle mounted!

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