MDF CNC

DIY MDF CNC Machine Is Small And Solid

June 7, 2015 by 21 Comments

In the world of hobby-level CNC cost and simplicity are usually the name of the game. Using inexpensive and easily found materials makes a big difference in the feasibility of a project. [FreeRider] had built a CNC router before but it was big, flexible and not as accurate as he wanted. He set off to design his own table top router, influenced from other designs found on the ‘net, but also keeping the costs down and ease of build up.

The machine frame is made from 3/4″ MDF and was cut on [FreeRider’s] first router, the JGRO. Notice how all the holes are counterbored for the many bolt heads. It is clear that much attention to detail went into the design of this machine. Aluminum angle act as linear rails on which v-wheel bearings travel. Skate bearings support 5/16″ threaded rod used as lead screws. Lead nuts are tapped HDPE blocks and seem to be doing a satisfactory job with minimal backlash.

[FreeRider] says his new machine is capable of 60 inches per minute travel, double that of his old machine. Since the new machine is stiffer, he’s able to route aluminum and has successfully made some brackets out of 1/8″ plate. He reports the dimensional accurate to be about 0.002-0.003 inches. For more inexpensive MDF-based CNC machines, check out this drawer slide bearing one or this one that uses a drill for a spindle.

Better VGA On The STM32F4

June 7, 2015 by 26 Comments

[Cliff] is pushing VGA video out of a microcontroller at 800×600 resolution and 60 frames per second. This microcontroller has no video hardware. Before we get to the technical overview, here’s the very impressive demo.

The microcontroller in question is the STM32F4, a fairly powerful ARM that we’ve seen a lot of use in some pretty interesting applications. We’ve seen 800×600 VGA on the STM32F4 before, with a circles and text demo and the Bitbox console. [Cliff]’s build is much more capable, though; he’s running 800×600 @ 60FPS with an underclocked CPU and most (90%) of the microcontroller’s resources free.

This isn’t just a demo, though; [Cliff] is writing up a complete tutorial for generating VGA on this chip. It begins with an introduction to pushing pixels, and soon he’ll have a walkthrough on timing and his rasterization framework.

Just because [Cliff] has gone through the trouble of putting together these tutorials doesn’t mean you can’t pull out an STM Discovery board and make your own microcontroller video hacks. [Cliff] has an entire library of for graphics to allow others to build snazzy video apps.

Monitoring Power With A 555

June 7, 2015 by 12 Comments

[Diederich] is running a Raspberry Pi loaded up with Pimatic, a great home automation server that does just about anything you can throw at it. One thing it doesn’t do is monitor electricity and gas directly from the meter – you’re going to need hardware for that. [Diederich] stepped up to the plate and built that hardware using just a 555 timer. The total cost of adding this to his Pimatic setup was less than a dollar.

The 555 can be used as a timer, a trigger, and a bunch of them can be cobbled together into a CPU. [Diederich] isn’t using some fancy logic here; he’s just using the 555 as a Schmitt trigger with a phototransistor and his electricity meter. The output of the 555 is connected to the GPIO of the Raspberry Pi, and a Python script ties into Pimatic.

It’s a neat solution that only costs a dollar, and using the 555 has a few advantages: the 555 makes it possible to use long and thin wires back to the Pi, which means [Diederich]’s Pi doesn’t have to be located right next to his meter.

Accessing A PBX Through Voice Channels

June 7, 2015 by 9 Comments

[Alessandro] is an unlucky VoIP PBX administrator that frequently has to deal with very, very dumb network policies. Often times, he’ll have to change something on his setup which requires him to go out to his client’s location, or ask a client to use Teamviewer so the appropriate change can be made from behind a firewall.

This isn’t the solution to the problem. It will, however, fix the problem. To get around these firewalls, [Alessandro] is using the voice channels he already has access to for changing configurations on his VoIP boxes.

The implementation of this uses the AX.25 amateur radio modules that can be found in just about every Linux distro. This, and an Alsa loopback device, allows [Alessandro] to access a terminal over a voice-only network. Is it a hackey kludge? Yep. Is it just a little bit dumb? So are the network policies that don’t allow [Alessandro] to do his job.

This build isn’t too dissimilar than a bunch of modems from the old BBS days, albeit with vastly more powerful software. [Alessandro] says you’re only going to get about 38400bps out of this setup, but it beats begging for help for remote access.

Mad Max Inspired Flamethrower Ukulele

June 7, 2015 by 21 Comments

The new Mad Max movie is getting a lot of buzz, and a few people are calling it a modern classic. There’s a flamethrower guitar in the movie, which means it’s time for cosplay accouterments. Our ‘ol buddy [Caleb] loves flamethrowers and poofers, so hacking together a Doof Warrior inspired flamethrowing ukulele was natural for him.

The fuel for this uke is a can of butane actuated with a caulking gun. This setup is actually pretty clever; by removing the locking tab on the caulking gun, butane is released when the gun’s trigger is squeezed, but stops when the trigger is released. The igniter is a simple grill igniter is used to light the gas.

[Caleb] is rather famous for his flamethrowing creations. His life-size fire-breathing piranha plant uses a similar setup to shoot fire.

Video below.

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Hackaday Prize Entry: 3D Printed Parametric Motrs

June 6, 2015 by 8 Comments

If you’re building something that moves, chances are you’ll be using an electric motor. There are tens of thousands of different motors out there, each with their own properties, speeds, torque, and sizes. How do you pick the right motor? Most of the time it’s a highly educated guess, but [Solenoid] has a better idea: just 3D print a motor designed by a calculator that will give you the properties you need

This entry for The Hackaday Prize is just a web-based calculator for motor designs that takes torque, speed, size, or form factor as an input and spits out a complete motor design. Sure, you’ll need to wind coils on a 3D printed frame, but this calculator removes the need to calculate inductance, coil capacitance, and all the other bits needed to construct an efficient motor.

While actual products made in the millions will still be using off the shelf motors, this project is perfect for one-offs. If you want to motorize a telescope mount, this project will design a motor given the power and resolution per steps required. If you want to build a wind turbine, this calculator will put blades right on the outrunner of a brushless motor. It’s a great project, and something we can’t wait to see the results of.

The 2015 Hackaday Prize is sponsored by:

Crowdfunding Follies: Debunking The Batteriser

June 6, 2015 by 144 Comments

It’s not on Kickstarter yet, but this product is already making its media debut, with features in all the tech blogs, an astonishing amount of print outlets, and spouted from the gaping maws of easily impressed rubes the world over. What is it? It’s the Batteriser, a tiny metal contraption that clips over AA, C, and D cells that reclaims the power trapped inside every dead battery. Yes, every dead battery you’ve ever thrown away still has up to 80% of its power remaining. Sounds like complete hogwash, right? That’s because it is.

[Dave Jones] put together a great video on the how comes and why nots of the Batteriser, and while doing so gives a great tutorial for debunking a product, heavily inspired by [Carl Sagan]’s Baloney Detection Kit. The real  debunking starts by verifying any assumptions, and the biggest fault of the Batteriser campaign is claiming 80% of a battery’s power is unused. Lucky for us, [Dave] has tons of tools and graphs to demonstrate this is not the case.

To verify the assumption that battery-powered devices will brown out after using only 20% of a battery’s available power, [Dave] does the most logical thing and looks at the data sheets for a battery. After using 20% of available power, these datasheets claim these batteries should be around 1.3V. Do devices brown out at 1.3V? Hook it up to a programmable power supply and find out.

It turns out every battery-powered device [Dave] could find worked perfectly until around 1.1V. Yes, that’s only 0.3V difference from 1.4V claimed by the patent for the Batteriser, but because of the battery discharge curve, that means 80% of the power in a normal device is already being used up. The premise of the Batteriser is invalid, and [Dave] demonstrates it’s a complete scam.

If a through debunking of the Batteriser’s claims wasn’t enough, [Dave] goes on to explain how it may actually be dangerous. The positive terminal of a battery is also the metal can, while the negative terminal is just a tiny nib of metal seperated from the rest of the battery by a gasket. Since the Batteriser is made of metal and serves as the ground for the boost converter circuit, it’s very, very close to shorting through the branding and logo emblazoned on a mylar wrapping each battery is shrouded with. One tiny nick in this insulator, and you have a direct short across the battery. That’s going to turn to heat, and there’s a lot of energy in a D cell; a failure mode for the Batteriser is a fire. That’s just terrible product design.

Video below.

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