Paraffin Oil and Water Dot Matrix Display

In preparation for Makerfaire, [hwhardsoft] needed to throw together some demos. So they dug deep and produced this unique display.

The display uses two synchronized peristaltic pumps to push water and red paraffin through a tube that switches back over itself in a predictable fashion. As visible in the video after the break, the pumps go at it for a few minutes producing a seemingly random pattern. The pattern coalesces at the end into a short string of text. The text is unfortunately fairly hard to read, even on a contrasting background. Perhaps an application of UV dye could help?

Once the message has been displayed, the water and paraffin drop back into the holding tank as the next message is queued up. The oil and water separate just like expected and a pump at the level of each fluid feeds it back into the system.

We were deeply puzzled at what appeared to be an Arduino mounted on a DIN rail for use in industrial settings, but then discovered that this product is what [hwhardsoft] built the demo to sell. We can see some pretty cool variations on this technique for art displays.

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Everyman’s Turbomolecular Pump

What can you do with a very good vacuum pump? You can build an electron microscope, x-ray tubes, particle accelerators, thin films, and it can keep your coffee warm. Of course getting your hands on a good vacuum pump involves expert-level scrounging or a lot of money, leading [DeepSOIC] and [Keegan] to a great entry for this year’s Hackaday Prize. It’s the Everyman’s Turbomolecular Pump, a pump based on one of [Nikola Tesla]’s patents. It sucks, and that’s a good thing.

The usual way of sucking the atmosphere out of electron microscopes and vacuum tubes begins with a piston or diaphragm pump. This gets most of the atmosphere out, but there’s still a little bit left. To get the pressure down even lower, an oil diffusion pump (messy, but somewhat cheap) or a turbomolecular pump (clean, awesome, and expensive) is used to suck the last few molecules of atmosphere out.

The turbomolecular pump [DeepSOIC] and [Keegan] are building use multiple spinning discs just like [Tesla]’s 1909 patent. The problem, it seems, is finding a material that can be made into a disc and can survive tens of thousand of rotations per minute. It’s a very, very difficult build, and a mistake in fabricating any of the parts will result in a spectacular rapid disassembly of this turbomolecular pump. The reward, though, would be great. A cheap turbomolecular pump would be a very useful device in any hackerspace, fab lab, or workshop garage.

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Programmable Pump Keeps Its Stick On The Ice

Need to water your plants? Pump some coolant on a mill? Fill a watermelon with booze? Never fear, because the third greatest Canadian behind [Alan Thicke] and [Bryan Adams] is here with the solution to all your problems! It’s a cordless pump for desktop CNC, repair, and horticulture that automates daily chores and pumps out exact amounts of liquid.

[Chris], [AvE], Bright Idea Workshop, or, ‘that guy that records videos in his shop’ is rather well-known around these parts; we’ve seen him make an $80,000 gold-plated cutting fluid pot, a copper laminate desk, and recharge his cell phone with a car and a pencil. He’s very, very good at futzing around in his shop and the dialog is the closest YouTube will ever get to Click and Clack the Tappet Brothers, albeit without wheezing laughter.

The Kickstarter is for a rechargeable cordless pump, controlled by a microcontroller, that dispenses liquids of varying viscosity onto the item of your choice. It’s perfect for adding cooling to a drill press, watering plants, or something or everything involving beer.

Details on the pump are a little sparse, but given the liquid never touches the pump we’re putting money on some type of peristaltic pump. Add volume measurement, programmable flow rate adjustment, a timer, and dispensing programmable volumes of liquid, and you’ve got something useful.

Thanks [Scott] for the tip.

Making the Dune “Pain Box” a Reality

If you are unfamiliar with Dune, then you may not know what the pain box is. The pain box is a fictional device that produces an excruciating burning sensation without causing any actual damage. [Bryan] has been working on a project to duplicate this effect in the real world. It sounds like he may be on the right path by using the “thermal grill illusion”.

The thermal grill illusion is a sensory trick originally demonstrated back in 1896. The trick is made up of two interlaced grills. One is cool to the touch, and the other is warm. If the user touches a single grill, they won’t experience any pain because neither temperature is very extreme. However if the user places their hand over the interlaced grills simultaneously they will immediately experience a burning heat. This usually causes the person to pull their hand away immediately. It’s a fun trick and you can sometimes see examples of it at science museums.

The thermal grill illusion sounded like the perfect way to make the pain box a reality. [Bryan] has set specific constraints on this build to make it more true to the Dune series. He wants to ensure the entire package fits into a small box, just big enough to place an adult hand inside. He also wants to keep safety in mind, since it has the potential to actually cause harm if it were to overheat.

[Bryan] has so far tried two methods with varying success. The first attempt involved using several thermoelectric coolers (TECs). [Bryan] had seen PCBs etched a certain way allowing them to radiate heat. We’ve seen this before in 3D printer surfaces. He figured if they could become hot, then why couldn’t they become cold too? His idea was very simple. He etched a PCB that had just two large copper pours. Each one branched out into “fingers” making up the grill.

Each side of the grill ultimately lead to a flat surface to which a TEC was mounted. One side was cold and the other was hot. Heat sinks we attached to the open side of the TECs to help with performance. Unfortunately this design didn’t work. The temperature was not conducted down to the fingers at all. The back side of the PCB did get hot and cold directly under the TECs, but that wouldn’t work for this illusion.

The latest version of the project scraps the PCB idea and uses small diameter copper tubing for the grill. [Bryan] is working with two closed loop water systems. One is for warm water and the other is for cold. He’s using an aquarium pump to circulate the water and the TECs to actually heat or cool the water. The idea is that the water will change the temperature of the copper tubing as it flows through.

While the results so far are better than the previous revision, unfortunately this version is having problems of its own. The hot water eventually gets too hot, and it takes over an hour for it to heat up in the first place. On top of that, the cold water never quite gets cold enough. Despite these problems, [Bryan] is hopefully he can get this concept working. He has several ideas for improvements listed on his blog. Maybe some Hackaday readers can come up with some clever solutions to help this project come to fruition.

Peristaltic Pump Moves Fluids Uphill Both Ways

Here’s a skill we should all probably have for after the apocalypse—the ability to build a cheap peristaltic pump that can transport highly viscous fluids, chunky fluids, or just plain water from point A to point B with no priming necessary. That’s exactly what [Jack Ruby] has done with some fairly common items.

He started with a springform cake pan from a thrift store, the kind where the bottom drops out like that centripetal force ride at the carnival. He’s using 2″ casters from Harbor Freight mounted to a block of wood. The casters go round and squeeze fluid through the hose, which is a nice length of heat-resistant silicone from a local homebrew shop. He’s currently using a drill to run the pump, but intends to attach a motor in the future.

[Jack]’s write-up is very thorough and amusing. Stick around to see the pump in action as well as a complete tour. You can also pump colored goo if you’re out of beer materials.

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The Flow Of Time Draws On A River

river

You would think Hackaday would see more projects from public art exhibitions. They really do have everything – the possibility to mount electronics to just about anything in a way that performs interesting but an ultimately useless function. So far, though, [Richard Schwartz’s] Flow of Time is on the top of a very short list of public art installations we like.

The idea behind the build is a German phrase that means something similar to ‘time trickles away’. [Richard]’s project implements this by printing the current time onto the surface of a flowing river in [Richard]’s native Innsbruck.

The build uses five micro piezo pumps to dispense food coloring from a bridge. Every minute, an Arduino pumps this food coloring in a 5×7 pixel digit to ‘write’ the time onto the surface of a river.

Surprisingly, [Richard]’s installation doesn’t require much upkeep. The pumps only use about 70ml of food coloring a day, and the entire device – including the Raspi WiFi webcam – is solar powered with a battery backup.

You can see a video of the time printing on a river below.

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Raspberry Pi automates your tomato farm

rpi-tomato-farming

Check out the tomato plants [Devon] grew using a monitoring system he built himself. It’s based around a Raspberry Pi. As far as grow controllers go it falls a bit short of full automation. That’s because the only thing it can actuate is the black water line seen hovering above the plants. But [Devon’s] work on monitoring and collecting sensor data should make it easy to add features in the future.

The moisture sensors pictured above monitor the soil in which the plants are growing. But he also has temperature and light sensors. These are very important when growing from seed and could be used in conjunction with a heating mat for plants that require higher soil temperatures (like pepper plants). The tomatoes are also pretty leggy. Now that he’s monitoring light levels it would be good to augment the setup with a grow light. A long term goal could even be a motorized bed which could raise the plants right up to the bulbs so they don’t reach for the light.

Don’t let the stars in our eyes distract you though. He’s done a ton of work on the project both with the physical build, and in plotting the data collected by the system. Great job!

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