Smarter-than-wood Saw Blade Makes Perfect Foldable Joints

[Andrew Klein] knows the pain of building drawers from plywood. It can be a pain to get all of the pieces measured and cut just right. Then you have to line them up, glue them together, and clamp them perfectly. It’s time-consuming and frustrating. Then one day it hit him that he might be able to make the whole process much easier using a custom saw blade.

The the video below, [Andrew] does a great job explaining how the concept works using a piece of paper. The trick is that the plywood must be cut in a very specific shape. This shape results in the plywood just barely being held together, almost as if it’s hinged. The resulting groove can then be filled with wood glue, and the plywood is folded over on itself. This folding process leaves no gaps in the wood and results in a strong joint. Luckily this special shape can be cut with a specialized saw blade.

This new process removes the requirement of having five separate pieces for a drawer. Instead, only four cuts are needed on a single piece of square plywood. The corners are then removed with a razor blade and all four sides are folded up and into place. [Andrew] shows that his prototype blade needs a little bit of work, but he’s so hopeful that this new invention will be useful to others. Continue reading “Smarter-than-wood Saw Blade Makes Perfect Foldable Joints”

Captain Hermano’s Mystery Box is Full of Puzzles

[Raffi] needed a birthday present idea but he wanted to do something extra special. He realized that a big part of gift giving is the anticipation and excitement of opening the present. In order to prolong this experience, [Raffi] built an electronic puzzle box. The box contains the final gift, but first a series of puzzles must be solved in order to open the box.

The project runs on an Arduino Mega. This is hooked up to several sensors, including a temperature sensor, GPS unit, and CO sensor. There is also an LCD screen and numeric keypad for user input and output. The project page contains a flow chart that shows all of the puzzles and their solutions. One of the more interesting puzzles requires the user to blow tobacco smoke into a tube. The CO sensor detects the smoke and unlocks the next puzzle.

Some of the puzzles require interacting with outside systems. For example, one puzzle requires the user to send an email to the fictional Captain Hermano’s email address. If the correct keyword is included in the email, the user will receive a reply with the code to enter into the box. Another puzzle requires the user to call a particular phone number and listen for another riddle. We’ve included the video demonstration below.

This isn’t the first puzzle box we’ve seen, but each one has its own special flair. This one is very well made and looks like a lot of care was put into it. We’ve seen another that uses only discrete components. We’ve seen yet another that uses Morse code. Continue reading “Captain Hermano’s Mystery Box is Full of Puzzles”

Acrylic enclosures use integrated clips to do away with fasteners

acrylic-clip-lock-enclosures

Here’s a design that lets you make acrylic enclosures without using fasteners. The red outline in the diagram above is a bit hard to make out. But look closely and you’ll realize that there is very little material which has been removed to form the clip. This uses the rigidity/flexibility of the material to form a spring that will hold a couple of pieces tightly together.

In a links post last year we looked at [Patrick Fenner’s] fantastic analysis of the strength of using kerf-bending to form several sides of a case out of one piece of material. He’s used that same analytic expertise to take a look into this design. He even suggests that making the cut on the hook-side a bit deeper will help improve the resilience of the part. If you have a laser cutter on hand and want to give this a try he’s posted the plans on Thingiverse.

Valentine’s puzzle box makes you work for what’s inside

valentines-puzzle-box

Here’s a new take on a gift box which has been locked from the inside. I doesn’t rely on GPS coordinates or a real-time clock to unfasten the latch. Instead, the box itself acts as a puzzle. You follow the visual and audio clues, turning the box along three axes in order to input the unlock code.

There are three different difficulty settings. The easiest uses the LED heart to indicate which direction to turn the box next. This is accompanied by a beep for correct or a longer tone for incorrect movements. On the medium setting you can only go by the tones, but once you screw up the lights will aid you in getting back to where you where when making the mistake. The impossible setting doesn’t use the lights at all.

[Matt] took inspiration from some reverse geocache projects featured here on Hackaday. He already had an STM32F3 Discovery board on hand which he received as a sample. It’s driving all of the electronics inside, with the on-board gyroscope as the input device. Don’t miss the video after the break to see how well the thing works.

Continue reading “Valentine’s puzzle box makes you work for what’s inside”

Box Maker extension for Inkscape

If you use Inkscape to lay out your laser cutter designs you might want to look into this box maker extension. Inscape is [Elliot’s] drawing software of choice since it’s easy to use, and it’s open source. After having to lay out the tabs for a box he decided it was worth his effort to develop a tool to do this automatically. The extension works inside of Inkscape, letting you start your projects with a set of automatically generated box sides.

The input window for the extension leaves you plenty of options for the joint design. In addition to the size of the box (inside or outside measurements can be selected), you need to enter the thickness of the material, the kerf size (how wide the cut will be), and how much clearance you want between the teeth. The width of the teeth is also configurable.

Our feature of a laser cut replacement case is what prompted [Elliot] to tip us off about his extension. That project used a web-based parts generator to do the joint design.

A mixer (re)built to travel

[Toby Cole] likes to mix tunes whenever he gets a chance. But the size of his DJ equipment made it a real bother to lug around with him. He does own a Behringer portable mixer but without cross faders it’s not really all that usable, and most of the other offerings don’t get good reviews. He ended up replacing the enclosure of a proper mixer in order to make it light and small. The growing availability of affordable laser-cut parts made this project possible.

Build Brighton, [Toby’s] local Hackerspace, has a laser cutter. So he knew that if he could figure out a smaller case design it would be a snap to get his parts made. He cracked open the heavy metal case on the KMX 100 mixer and found it had a ton of extra room inside. He designed all of the plates using a digital calipers to properly space the holes and text labels. These designs were combined with BoxMaker to produce the files the laser cutter needed. The first prototype was cut from cardboard, with the finished product cut from 3mm plywood.

Building better cases with a laser cutter

[Ryan] just got his Raspberry Pi, and what better way to add a new toy to your workbench than by building a case for it? Using a laser cutter and 3D printer, [Ryan] managed to make a case that is sure to be the envy of all the other tinkerers at his hackerspace.

The build started off with a piece of dark red acrylic in a laser cutter. After cutting the Raspberry Pi logo out of this acrylic, [Ryan] cut the same logo – a little bit larger – out of plywood. Because he was very careful to measure the kerf (or the width of the laser beam/saw blade/what have you), the wooded version of the Raspi logo fit snugly inside the acrylic cut out.

The sides of the enclosure are a single piece of plywood with a kerf bend, making for a very attractive rounded case. Finally, the Raspberry Pi is mounted on a Pi plate printed on a Ultimaker.

For as many builds we see using a laser cutter here on Hackaday, there’s surprisingly little information on exploiting the true potential of these machines with marquetry, intarsia, or fretwork. Enclosures are always cool, so if you have a very elegant laser cut box, send it in and we’ll put it up.