Massive Wood Joints With Chainsaw Mortiser

mortise-tenonOne common joinery method used in wood working is the mortise and tenon. A mortise is basically a hole in a piece of wood and the tenon is another piece of wood cut to tightly fit in that hole. The tenon is usually secured in place with either glue or a wooden pin or wedge.

The folks over at [WayOutWest] were building a fence and needed a way to cut a bunch of mortises in 4×4 inch posts to accept 2×6 inch rails. Although they had a chainsaw, trying to cut a mortise with it by hand turned out to be super dangerous because the chainsaw would kick up every time the tip of the blade touched the wood. The team had some parts kicking around so they made a fixture to hold the chainsaw as it is plunged into the 4×4’s.

The contraption’s frame is made from an old scaffolding stand and the slides are just pipes inside of pipes. The chainsaw is bolted to the slide and a lever moves it forward and back. A second lever moves the piece of wood getting mortised up and down so that the mortise can be cut to any width. This is a pretty ingenious build that only cost a little effort and will end up saving a bunch of time mortising countless fence posts.

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FPGA Based Ambilight Clone

The Philips Ambilight – a bunch of rear-facing RGB LEDs taped to the back of a TV – is becoming the standard project for anyone beginning to tinker with FPGAs. [DrX]’s is the best one we’ve seen yet, with a single board that reads and HDMI stream, makes blinkey lights go, and outputs the HDMI stream to the TV or monitor.

[DrX] is using an FPGA development board with two HDMI connectors – the Scarab miniSpartan6+ – and a strand of WS2801 individually addressable RGB LEDs for this project. With a bit of level shifting, driving the LEDs was easily taken care of. But what about decoding HDMI?

Most of the project is borrowed from a project that displays a logo in the corner of a 720p video stream. The hardware is the same, but for an Ambilight clone, you need to read the video stream and process it, not just write to it. By carefully keeping track of the R, G, and B values for each pixel along with the pixel clock,  the colors along the edge of a display can be averaged. It’s not as difficult or as memory-intensive as building a frame buffer; nearly all of the picture data is thrown out when assembling the averages around the perimeter of the display. It does work, though.

After figuring out the average color around the perimeter of the display, it’s just a simple matter of driving the LEDs. Tape those LEDs to the back of a TV, and there’s an Ambilight clone, made with an FPGA.

[DrX] has a few videos of his project in action. You can check those out below.

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Hacklet 44 – Teardowns

Just about every hacker, maker and tinkerer out there received their early education the same way: A screwdriver in one and a discarded bit of electronics in the other. There is no better way to find out how something works than cracking it open and examining each piece.  In recent years, teardown videos have become popular on YouTube, with some of the great examples coming from users like [EEVblog], [mikeselectricstuff], and [The Geek Group]. This week’s Hacklet is all about the best teardown projects on Hackaday.io!

copierWe start with [zakqwy] and his Savin C2020 Teardown. Photocopiers (and multifunction machines) are the workhorses of the modern office. This means there are plenty of used, abused, and outdated photocopiers available to hackers. [Zakqwy] got this monster when it started misbehaving at his office. Copiers are a venerable cornucopia of motors, gears, sensors (lots and lots of breakbeam sensors) and optics. The downside is toner: it’s messy, really bad to breathe, and if you don’t wear gloves it gets down into the pores of your skin, which takes forever to get out. [Zakqwy] persevered and found some awesome parts in his copier – like an  Archimedes’ screw used to transport black toner.

wemoNext up is [Bob Blake] with Belkin WeMo Insight Teardown. [Bob] wanted a WiFi outlet, but wasn’t about to plug something in to both his power grid and his network without taking it apart first. [Bob] did an awesome job of documenting his teardown with lots of great high resolution photos – we love this stuff! He found a rather well thought out hardware design. The Insight has 3 interconnected PCBs inside. The power switching and supply circuits are all on one board. It includes slots and the proper creep distances one would expect in a design that will be carrying 120V AC mains power. A small daughter board holds an unknown chip – [Bob] is guessing it is the power sensing circuitry. A third board a tucked in at the top of the module holds the main CPU, a Ralink/MediaTek RT5350F SoC, RAM, and the all important WiFi antenna.

 

x-ray[Drhatch] took things into the danger zone with an X-ray Head Teardown. We’re not sure if [Drhatch] is a real doctor, but he does have a Heliodent MD dental X-ray head. Modern X-ray machines are generally radiation safe if they’re not powered up. Radiation isn’t the only dangers to worry about though – there are latent charged capacitors and cooling oils which may contain nasty chemicals like PCBs, among other things. [Drhatch] found some pretty interesting design decisions in his X-ray head. The tube actually fires through the cylindrical high voltage transformer. This means the transformer acts as a beam collimator, focusing the X-ray beam down like a lens. He also found plenty of lead shielding. Interestingly there are two thickness of lead in the housing. Shielding close to the tube is 1 mm thick, while shielding a bit further away is only 0.7 mm thick.

 

3phaseFinally, we have [danielmiester] with Inside a 3ph AC Motor Controller(VFD). [Daniel] tore down a Hitachi Variable-Frequency Drive (VFD) with the hopes of creating a frequency converter for a project. These high voltage, high power devices have quite a bit going on inside, so the conversion became a teardown project all its own. VFDs such as this one are used in industry to drive high power AC motors at varying speeds efficiently. As [Daniel] says, the cheaper ones are ” just really fancy PWM modules”. Handling 1.5 kW is no joke though. This VFD had a large brick of power transistors potted into its heat sink. The controller board was directly soldered to the transistors, as well as the rectifier diodes for the DC power supply. [Daniel] was doing some testing with the unit powered up, so he built a custom capacitor discharge unit from 3 C7 Christmas lights. Not only did they keep the capacitors discharged, they provided an indication that the unit was safe. No light means no charge.

Not satisfied? Want more teardown goodness? Check out our freshly minted Teardown List!

That’s about all the time we have for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

wooden wood lathe

Mini Wood Lathe Made Of….. Wood?

When someone says ‘wood lathe’ the average person would think of a lathe used for turning pieces of wood into ornate shapes. But what if that lathe was also made of wood. Would that be a wood wood lathe? Instead of wondering the answer to that very unimportant question, young 15 year-old [laffinm] decided to actually build a wood wood lathe from plans he found in a magazine.

As you would expect, a 15 year-old’s budget is certainly not going to be very large. [laffinm] started by gathering plywood scraps left over at construction sites. The lathe bed, head stock, tail stock, tool rest and motor mount are all made from 3/4″ plywood. The tool rest and tail stock have knobs that allow loosening of each part so that they can be moved to any location on the bed.

Out back, [laffinm] made his own live center for the tail stock out of a chuck and bearing assembly that he pulled from an old drill. The tail stock supports were drilled out to fit the bearings which were epoxied in place. The live center and tail stock combination supports the right side of the work piece that is being turned on the lathe.

In the end the lathe came out pretty darn well. We here at Hackaday love projects that make use of recycled parts and this project sure does that as most of the parts were scavenged or obtained for free with the only exceptions a v-belt and some nuts and bolts. If you’d like to see the build process in detail, [laffinm] has a very complete Instructable with 3 build videos, the first of which you can find after the break.

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The Raspberry Pi Action Camera

Action cameras like the GoPro, and the Sony Action Cam are invaluable tools for cyclists and anyone else venturing into the great outdoors. These cameras are not really modifiable or usable in any way except for what they were designed for. [Connor] wanted a cheaper, open-source action camera and decided to build one with the Raspberry Pi.

[Connor]’s Pi action cam is built around the Raspberry Pi Model A+ and the Pi camera. This isn’t a complete solution, so [Connor] added a bluetooth module, a 2000 mAh battery, and a LiPo charger.

To keep the Pi Action Cam out of the elements, [Connor] printed an enclosure. It took a few tries, but eventually he was able to mount everything inside a small plastic box with buttons to start and stop recording, a power switch, and a USB micro jack for charging the battery. The software is a script by [Alex Eames], and the few changes necessary to make this script work with the hardware are also documented.

This was the most intensive 3D printing project [Connor] has ever come up with, and judging by the number of prints that don’t work quite right, he put a lot of work into it. Right now, the Pi action cam works, but there’s still a lot of work to turn this little plastic box into a completed project.

Lego Flip-dot Display

We don’t need to mention that flip-dot displays are awesome. They use no power except in transitions, are visible on even the brightest of days, and have a bit of that old-school charm. So then it stands to reason that the flip-dot display that [AncientJames] made out of LEGO is awesome-plus. Heck, it even spells out “awesome”.

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Audio Algorithm Detects When Your Team Scores

[François] lives in Canada, and as you might expect, he loves hockey. Since his local team (the Habs) is in the playoffs, he decided to make an awesome setup for his living room that puts on a light show whenever his team scores a goal. This would be simple if there was a nice API to notify him whenever a goal is scored, but he couldn’t find anything of the sort. Instead, he designed a machine-learning algorithm that detects when his home team scores by listening to his TV’s audio feed.

goal[François] started off by listening to the audio of some recorded games. Whenever a goal is scored, the commentator yells out and the goal horn is sounded. This makes it pretty obvious to the listener that a goal has been scored, but detecting it with a computer is a bit harder. [François] also wanted to detect when his home team scored a goal, but not when the opposing team scored, making the problem even more complicated!

Since the commentator’s yell and the goal horn don’t sound exactly the same for each goal, [François] decided to write an algorithm that identifies and learns from patterns in the audio. If a home team goal is detected, he sends commands to some Phillips Hue bulbs that flash his team’s colors. His algorithm tries its best to avoid false positives when the opposing team scores, and in practice it successfully identified 75% of home team goals with 0 false positives—not bad! Be sure to check out the setup in action after the break.

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