Water-dosing coffee maker augmentation

[Arthur Benemann] has the worst part of making coffee licked. His add-on for a drip coffee maker fills the water to the proper levels for you, saving the drudgery of rinsing out the carafe, carefully filling it to the appropriate level, then pouring it into the machine without getting everything wet. This isn’t limited to a full pot, but is user selectable by the cup based on how many times in a row you hit that red button. One LED gives feedback on the selected mode, then the device uses a washing machine water valve to turn on the tap for the appropriate amount of time. We’re a little bit leery of connecting homebrew hardware to the water pipes in our house. Make sure you’ve done a good job of debugging so that an infinite loop doesn’t flood you out.

Attitude control for a really big rocket

If this is meant for a model rocket it must be the biggest we’ve ever seen. [Scott] and [Trevor] took on the task of building a rocket attitude control system after reading about some research on the topic. But that researcher only tested the theories using simulations so they set out to build their own. The prototype above has a tank of compressed Nitrogen which can hold up to 3000 PSI. You can begin to understand why this needs to be used with a big rocket. The pressurized gas is connected through a regulator to four valves which feed nozzles around the circumference of the fuselage. An Arduino takes readings from a gyroscope and actuates the gas valves via a relay board.

You can check out the test rig in the video after the break. The prototype is suspended horizontally from a wire and its orientation held at one position by the system. There’s also a paper (PDF) if you’re interested in the equations that went into the stabilization control. This system would have been right at home on that huge sugar rocket we saw back in October.

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Aquarium water exchanger

If you want happy fish you’re going to need to do regular aquarium maintenance. Part of this is exchanging a portion of the tank’s water on a regular basis. [Bill Porter] came up with a water exchanger that means less manual labor, but makes the process just a bit more complicated.

So, what he would do before is fill a few buckets from the aquarium and dump them down the toilet. Then mix up a few buckets of salt water and add them back to the aquarium. This meant carrying several trips worth of heavy, dripping buckets through the house. What he has now is a gravity fed system into the orange bucket with a bilge pump to evacuate the old water from that bucket into the kitchen sink. The bilge can then be used to circulate water through the aquarium and the bucket, while filling with a hose from the kitchen sink and mixing in salt and chemicals. Less trips, no drips, but you’ve got to know what you’re doing with all of those valves.

We love seeing aquarium hacks like [Bill's], or cooling the tank lights while heating the water, or just a fancy lighting setup in general. So if you’ve got some of your own, don’t forget to send in a tip about them.

Water-blob launcher

This rifle-shaped water cannon looks great and packs a big punch. We guess you could say that it’s a water balloon launcher, but the balloons are torn off and drop like the wad from a shotgun shell when fired. So we think this launches water blobs, or orbs, or something along those lines.

[Wolf] built it using PVC and some brass fittings that allow for the injection of compressed air. There’s a slick valve system that he developed which we don’t get a great look at in the build pictures. Fortunately, there’s an animated GIF that shows the various stages. Using his valve there’s no need for any electrical system like a lot of other pneumatic launcher systems use.

Just like the water-filled ping-pong gun, you’ve got to be careful with this thing. As you can see in the clip after the break there’s lethal force behind these projectiles. Especially when [Wolf] swaps out the water balloons for big steel darts.

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Build a confetti cannon for your next party

[Scott] built a confetti canon to spice up the party. It’s pneumatic and re-purposes a fire extinguisher as the air tank. He had a refillable extinguisher that used water instead of chemical retardant. After emptying the water and ensuring all of the pressure had been release he swapped the hose and nozzle for a sprinkler solenoid valve. Securing the extinguisher’s actuator lever with a pipe clamp holds the internal valve open, leaving the solenoid to control the pressure release. This way the canon can be fired electronically, or manually.

This type of solenoid valve is a popular choice with pneumatic canons. We suppose you could even adapt this for use as a T-shirt cannon.

[Thanks BoBeR182]