Make Your Own Compound Bow from PVC Pipe

Have you ever wanted to make your own compound bow for fun or even fishing? [New creative DIY] shows us how in their YouTube video. Compound bows are very powerful in comparison to their longbow grandparents, relying on the lever principle or pulleys. meaning less power exertion for the same output.

Compound bows can be really sophisticated in design using pulleys and some exotic materials, but you can make your own with a few nuts and bolts, PVC pipe, string and a tyre inner tube. The PVC pipe can be melted into shape using a heat source such as a portable stove or even a blow torch, and once you have shaped your bow you will want to put a small piece of pipe at both ends with a nut and bolt. Then you can use rubber to give the flexibility your bow needs to shoot arrows, using the tyre inner tube cut to the right size. A piece of string for the ends of your arrows to rest on is then all you need, attach this to either end of your pipe and you should have a DIY PVC compound bow ready for shooting arrows. Alternatively you could always make a recurve bow out of skis.

–Update [Leithoa] in the comments has pointed out this is neither a bow nor a compound and that they are often confused. This is actually a slingshot, of sorts.–
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Hackaday Prize Entry: Archelon ROV Explores the Ocean

Acendtech Robotics is a 4H robotics club located in Freehold, NJ, and their centerpiece project is the Archelon, an underwater drone they built out of PVC pipes. It’s also a Hackaday Prize entry designed to monitor marine traffic, the seabed, piers, jetties, and other underwater constructions.

The Archelon uses eight thrusters constructed out of bilge pumps that have been hacked to add a propeller, leaving the motor sealed safely inside.

The ROV’s motors are controlled by an Arduino Mega along with two motor driver boards, each board driving two pairs of DC motors. There’s also a robot claw rotated by another modified bilge pump, opened and closed by a waterproof servo. The on-board electronics including a Teensy 3.2 are sealed inside a 1/2″ acrylic tube sealed with rubber o-rings and custom-milled stainless steel endcaps. Connected to the Teensy are the ROV’s cameras as well as an ATTiny88, which in turn control the motors.

Students working with the Archelon learn not only the technical aspects of building a ROV like assembly and programming, but also its mission, learning how to take test samples of agar to study pollutants in the maritime environment.

Holman is Your Phone’s Best Friend

Let’s get something straight right up front: this isn’t much of an electronics project. But it is a very artistic 3D printing project that contains some electronics. [Sjowett] used an off-the-shelf class D amplifier with BlueTooth input to create a simple BlueTooth speaker with a subwoofer. As you can see from the pictures, woofer is exactly the term to use, too.

The clever mechanical design uses 3D printing and common metric PVC pipe. That’s a great technique and resulted in a very clean and professional-looking build. If you don’t have easy access to metric pipe, you could print the pipes, but it will take longer and might not look quite as good.

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Build Your Own High Power Air Cannon Out Of PVC

[NightHawkInLight] a.k.a. [Ben] recently built an awesome high power air cannon out of PVC pipe. PVC air cannons are great, and everyone should build one of these at some point in their life, but what really makes this build exceptional is the valve. [Ben] created a piston valve for this cannon that can be built with parts sourced from your local home supply store. Anyone can build this thing, and everyone should.

Instead of using a ball valve or other such contrivance to dump air directly from a reservoir into the chamber of this PVC air cannon, [Ben] is using a much more clever design. This is a barrel sealing PVC air cannon, with a moving piston sealed against a rubber hose clamp in the barrel. Adding air through the fill valve moves the piston forward, allowing air to leak into the reservoir. The air supply is then disconnected, and the trigger released causing the piston to move backward. This releases all the air in the reservoir into the barrel instantaneously, resulting in faster ping pong balls and potatoes.

The original trigger for this high power PVC air cannon used a simple ball valve for the trigger. [Ben] didn’t like this solution – it was hard to open and somewhat unergonomic. The ball valve trigger has since been replaced with a valve from a sprinkler system, giving this high power PVC air cannon a fancy brass trigger. It looks awesome, and can kill a watermelon from twenty yards. What more could you want in a high power PVC air cannon?

You can check out the videos for this build – including a guide for the clever piston valve – below.

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Make a PVC Drill Press

There are two types of people in this world: people who think that PVC is only suitable for plumbing, and people who don’t even know that you can use PVC to carry water. Instructables user [amjohnny] is clearly of the latter school. His PVC Dremel drill press is a bit of an oldie, but it’s still a testament to the pipefitter’s art. And you can watch it in action in the video embedded below.

Things we particularly like about this build include the PVC parallelogram movement, springs around tubes to push the Dremel head back up, and the clever use of a T-fitting and screw plug to hold the press in its lowest position. We wonder how one could add a depth stop to this thing. No matter, we love watching it work.

Anyway, this is just one hack of many that emphasizes the importance of a drill press in basically anyone’s life, as well as the ease of DIY’ing into one. If you’re in the PVC-haters camp, but have some scrap wood and drawer slides or plastic offcuts lying around, you have the makings of a rudimentary press — a welcome tool in the shop.

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Hackaday Links: March 12, 2017

The world’s first public installation of a solar roadway caught fire or something.

Hey hardware nerds in the UK! Nottingham is having its first monthly hardware meetup. This get together is being put together by [Spencer], creator of the extremely popular RC2014 Homebrew Z80 computer kit. The meetup is free, and it’s happening this Tuesday.

[danjovic] sent in a link to this YouTube channel of a guy building stuff out of PVC sheets and CA glue. There’s a lot of stuff in here from a PVC tripod to instructions on how to get PVC sheets out of PVC pipe. Small warning: this is PVC, and it will kill you instantly, for reasons we can’t yet determine. Additionally, he’s heating PVC, which means cancer for your yet-unborn great-grandchildren. How it both kills you while still allowing you to breed is beyond our comprehension. That’s how bad PVC really is.

NASA has updated their available software catalog. If you want to go to Saturn, you first have to go to Venus three times. Here’s a tool that packs batteries. You should build a router for the interplanetary Internet.

[jlbrian7] is Breaking Android over on

Last week, we had a Raspberry Pi Hack Chat with [Roger Thornton], the principal hardware engineer at Raspberry Pi. We talked about the hardware that goes into the Raspberry Pi (and the new Pi Zero W), and gave away a few Pi Zero Ws to a few people on that had great ideas for a project. One of the winners of a free Raspberry Pi Zero W was [arsenijs] for his Raspberry Pi Project. This is a really great project that uses a Raspberry Pi and Raspberry Pi accessories. It’s pushing the envelope of what a Pi can be, and a free Raspberry Pi Zero W couldn’t have gone to a more worthy project.

What are you doing the weekend of March 31st? We’re going to New Jersey for the Vintage Computer Festival East. This is one of the better cons we go to. Maybe this year we’ll organize a trip to the pinball museum in Asbury Park.

PVC Submersible ROV

[mark.brubaker.1] and his crew decided to make a submersible for a school project using PVC pipes as a frame. It has two motors on the back to provide forward thrust and steering as well as a horizontal mounted motor in the middle of the PVC chassis to provide up and down thrust. They used regular motors which they waterproofed by inserting them inside a case full of plumbers wax. We’re not sure how long this will hold at the bottom of the ocean, but it works fine for a school project in the pool. Here’s the instructions on how to make one.

The build is completely analog, the controller is a board with three switches which individually control the different motors. So if you want to turn left, you fired up the right motor. For right you do the opposite and fire up the left motor. Up and down, well, you get the picture. If you have a swimming pool, lake or some water body nearby and you’re looking for a weekend project with your kids, this is a great tip. It’s not an Arduino controlled robot fish, but it’s a first step in that direction; you can later on use the frame to improve on the design and add some electronics.

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