Hackaday Prize Entry: Collaborative Water Purification

Look over any description of a water treatment plant, and you’ll find a description that includes the words, ‘coagulation tanks’. What are these treatment plants coagulating? You don’t want to know. How are they doing it? With chemicals and minerals. Obviously, there’s something else that can be done.

For their Hackaday Prize entry, [Ryan], [designbybeck], [Clint], [Wanda] and [Maker Mark] are investigating electrocoagulation. It’s an alternative to a frothy brew of chemicals that uses electricity to pull pollutants out of the water.

Right now, the tests are much smaller in scale than the tens of thousands of gallons you’d find at a water treatment plant. In fact, the test rig is only a 16-ounce mason jar. While this isn’t large enough to precipitate pollutants out of a household water supply, it is big enough for a proof of concept.

The team is using two electrodes for this build, one aluminum, and one iron. These electrodes are connected via alligator leads to the electronics board they’ve built. This electronics board is basically just an H-Bridge (used so they can reverse the polarity of the field emitter and prevent a buildup of gunk on the electrodes) and a few connectors to a power supply. The results are encouraging; they have a few time-lapse videos of a mason jar of dirty water clearing up with the power of electricity. It’s a great project with some great documentation. The team already has a bunch of updates on their project and instructions on how to replicate their hardware. You can check out those videos below.

Continue reading “Hackaday Prize Entry: Collaborative Water Purification”

Cordless Water Pump!

A water pump is one of those items that are uncommonly used, but invaluable when needed. Rarer still are cordless versions that can be deployed at speed. Enter [DIY King 00], who has shared his build of a cordless water pump!

The pump uses an 18 volt brushed motor and is powered by an AEG 18V LiPo battery. That’s the same battery as the rest of [DIY King]’s power tools, making it convenient to use. UPVC pipe was used for the impeller — with a pipe end cap for a housing. A window of plexiglass to view the pump in motion adds a nice touch.

A bit of woodworking resulted in the mount for the pump and battery pack, while a notch on the underside allows the battery to lock into place. Some simple alligator clips on the battery contacts and the motor connected through a switch are all one needs to get this thing running.

Continue reading “Cordless Water Pump!”

Tear Gun Transmutes Emotions Into Firepower

Frustration is tough to deal with. When driven to the point of tears it’s sometimes a short step to lashing out irrationally. Focus in these situations helps, channeling your frustration into something useful. [Yi-Fei Chen] has done that — quite literally — by designing a gun that fires her shed tears.

The gun’s design manifested following a strenuous midterm presentation. Her insistent tutor drove her to tears as frustration clashed with the deep cultural values of her native Taiwan which prevented her from speaking up against authority.

A silicone cup resting against her cheek collects the tears which flow into a chamber of the gun to be frozen. Removing the safety slide preps the round to be fired by the pressure plate trigger on the gun’s rear. It’s simple and it works — tutors beware.

Continue reading “Tear Gun Transmutes Emotions Into Firepower”

Detecting Water With and Without Headaches

In Texas — at least around Houston — we don’t have basements. We do, however, have bilges. Both of these are subject to taking on water when no one is paying attention. A friend of mine asked me what I thought of an Instructable that showed how to make a water sensor using a few discrete components. The circuit would probably work — it relied on the conductivity of most water to supply enough current to a bipolar transistor’s base to turn it on.

It is easy to overthink something like this, so I told my friend he should go with something a little more old-fashioned. I don’t know the origin of it, but it is older than I am. You can make a perfectly good water detector with things you probably already have around the house. My point isn’t that you should (or shouldn’t) construct a homemade water sensor. My point is that you don’t always need to go to the high-tech solution.

Continue reading “Detecting Water With and Without Headaches”

How Hot is Your Faucet? What Color is the Water?

How hot is the water coming out of your tap? Knowing that the water in their apartment gets “crazy hot,” redditor [AEvans28] opted to whip up a visual water temperature display to warn them off when things get a bit spicy.

This neat little device is sequestered away inside an Altoids mint tin — an oft-used, multi-purpose case for makers. Inside sits an ATtiny85 microcontroller  — re-calibrated using an Arduino UNO to a more household temperature scale ranging from dark blue to flashing red — with additional room for a switch, while the 10k ohm NTC thermristor and RGB LED are functionally strapped to the kitchen faucet using electrical tape. The setup is responsive and clearly shows how quickly [AEvans28]’s water heats up.

Continue reading “How Hot is Your Faucet? What Color is the Water?”

Putting Sand, Water, and Metal into A 3D Print

[Adam] over at Makefast Workshop writes about some of the tests they’ve been running on their 3D printer. They experimented with pausing a 3D print midway and inserting various materials into the print. In this case, sand, water, and metal BBs.

The first experiment was a mixture of salt and water used to make a can chiller for soda or beer (the blue thing in the upper right). It took some experimentation to get a print that didn’t leak and was strong. For example, if the water was too cold the print could come off the plate or delaminate. If there was too much water it would splash up while the printer was running and cause bad layer adhesion.

They used what they learned to build on their next experiment, which was filling the print with sand to give it more heft. This is actually a common manufacturing process — for instance, hollow-handled cutlery often has clay, sand, or cement for heft. They eventually found that they had to preheat the sand to get the results they wanted and managed to produce a fairly passable maraca.

The final experiment was a variation on the popular ball bearing prints. Rather than printing plastic balls they designed the print to be paused midway and then placed warmed copper BBs in the print. The printer finished its work and then they spun the BB. It worked pretty well! All in all an interesting read.

Enjoy The Last Throes of Summer With a Nice Pool Automation Project

[Ken Rumer] bought a new house. It came with a troublingly complex pool system. It had solar heating. It had gas heating. Electricity was involved somehow. It had timers and gadgets. Sand could be fed into one end and clean water came out the other. There was even a spa thrown into the mix.

Needless to say, within the first few months of owning their very own chemical plant they ran into some near meltdowns. They managed to heat the pool with 250 dollars of gas in a day. They managed to drain the spa entirely into the pool, but thankfully never managed the reverse. [Ken] knew something had to change. It didn’t hurt that it seemed like a fun challenge.

The first step was to tear out as much of the old control system as could be spared. An old synchronous motor timer’s chlorine rusted guts were ripped out. The solar controler was next to be sent to its final resting place. The manual valves were all replaced with fancy new ones.

Rather than risk his fallible human state draining the pool into the downstairs toilet, he’d add a robot’s cold logical gatekeeping in order to protect house and home. It was a simple matter of involving the usual suspects. Raspberry Pi and Arduino Man collaborated on the controls. Import relay boards danced to their commands. A small suite of sensors lent their aid.

Now as the soon-to-be autumn sun sets, the pool begins to cool and the spa begins to heat automatically. The children are put to bed, tired from a fun day at the pool, and [Ken] gets to lounge in his spa; watching the distant twinkling of lights on his backyard industrial complex.