Boost Converter Functionality At Rock-Bottom Prices

March 27, 2017 by 16 Comments

Linear voltage regulators are pretty easy to throw into a project if something in it needs a specific voltage that’s lower than the supply. If it needs a higher voltage, it’s almost just as easy to grab a boost converter of some sort to satisfy the power requirements. But if you’re on a mission to save some money for a large production run, or you just like the challenge of building something as simply as possible, there are ways of getting voltages greater than the supply voltage without using anything as non-minimalistic as a boost converter. [Josh] shows us exactly how this can be done using a circuit known as a charge pump to drive a blue LED.

One of the cool things about AVR microcontrollers is that they can run easily on a coin cell battery and source enough current to drive LEDs directly from the output pins. Obviously enough, if the LED voltage is greater than the voltage of the power supply, this won’t work. That is, unless you have a spare diode and capacitor around to build a charge pump.

The negative charge pump works by charging up a capacitor that is connected to an AVR pin, with the other side between the LED and a garden-variety diode to ground. That results in a roughly (VCC – 0.7) volt difference across the capacitor’s plates. When the AVR pin goes low, the other side of the capacitor goes negative by this same amount, and this makes the voltage across the LED high enough to light up. Not only is this simpler than a boost converter, but it doesn’t need any bulky inductors to work properly.

Will this work for any load? Am I going to start any fires by overdriving the LED? Luckily, [josh] answers all of these questions and more on the project page, and goes into some detail on the circuit theory as well. Granted, the charge pump doesn’t have the fine control over the power supply that you can get out of a buck or boost converter (or any switch-mode power supply). But it does have good bang-for-the-buck.

MRRF 17: Laser Resin Printers

March 26, 2017 by 19 Comments

The Midwest RepRap Festival is the best 3D printer con on the planet. In the middle of Indiana, you’ll find the latest advances for CNC hot glue guns and the processes that make squirting filament machines better, more accurate, and more efficient. There’s more to 3D printing than just filament-based machines, though, and for the last few MRRFs we’ve been taking a look at resin-based machines.

While most of the current crop of resin printers use either DLP projectors or LCDs and a big, bright backlight [Mark Peng]’s Moai printer uses a 150 mW laser diode and galvos. This is somewhat rare in the world of desktop 3D printers, thanks in no small part to the ugliness between Formlabs and 3D Systems. Still, it’s a printer that looks fantastic and produces prints that are far beyond what’s possible with a filament-based machine.

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Turn That Pi Zero Into A Streaming Camera, Step-by-Step

March 26, 2017 by 30 Comments

What makes [mwagner1]’s Raspberry Pi Zero-based WiFi camera project noteworthy isn’t so much the fact that he’s used the hardware to make a streaming camera, but that he’s taken care to document every step in the process from soldering to software installation. Having everything in one place makes it easier for curious hobbyists to get those Pi units out of a drawer and into a project. In fact, with the release of the Pi Zero W, [mwagner1]’s guide has become even simpler since the Pi Zero W now includes WiFi.

Using a Raspberry Pi as the basis for a WiFi camera isn’t new, but it is a project that combines many different areas of knowledge that can be easy for more experienced people to take for granted. That’s what makes it a good candidate for a step-by-step guide; a hobbyist looking to use their Pi Zero in a project may have incomplete knowledge of any number of the different elements involved in embedding a Pi such as basic soldering, how to provide appropriate battery power, or how to install and configure the required software. [mwagner1] plans to use the camera as part of a home security system, so stay tuned.

If Pi Zero camera projects catch your interest but you want something more involved, be sure to check out the PolaPi project for a fun, well-designed take on a Pi Zero based Polaroid-inspired camera.

Hackaday Links: March 26, 2017

March 26, 2017 by 39 Comments

PoC||GTFO 14 is now out. It’s a 40 MB PDF that’s also a Nintendo Entertainment System ROM, and a Zip archive. Pastor Laphroaig Screams High Five To The Heavens As The Whole World Goes Under. Download this, but don’t link – host it yourself. Bitrot will be the end of us all.

[Photonicinduction] is back. The guy best known for not starting an electrical fire in his attic has been working through some stuff recently. He got married, went to India, and he’s going to try to blow a five thousand amp fuse. Good on him.

There’s a certain segment of the Internet that believes the Raspberry Pi Zero doesn’t exist. The logic goes something like this: because I can’t buy a Ferrari right now, Ferraris don’t exist. Now there’s a new and improved website that checks if the Pi Zero and Pi Zero W are in stock: thepilocator.com. It checks a dozen or so online stores for the Pi Zero and Pi Zero W. Guess what? They’re mostly in stock.

[bxcounter] built a PC case and holy crap this thing is incredible. This case is made out of Paulownia wood, and is made up out of fifty pieces held together with magnets. This thing is hand-carved and looks fantastic. Inside is a Mini-ITX motherboard, an i3, a Gigabyte ITX-sized 1060, and an SSD. It’s no powerhouse, but then again it’s not overkill, either. This is a fantastic addition to any battlestation.

As most hackerspaces do, the Omaha Maker Group had a storage problem. Previously, members used plastic totes someone picked up as surplus, but these totes were in short supply. Banker’s Boxes are a better idea, but how to store them? A box case. This ‘bookcase for boxes’ holds 21 standard Banker’s Boxes and only uses two full sheets of MDF in its construction.

MRRF 17: True Color 3D Printing

March 26, 2017 by 43 Comments

3D printing has evolved to a point where dual extrusion isn’t really that special anymore. A few years ago, a two-color frog print would have been impressive, but this isn’t the case anymore. The Midwest RepRap Festival is all about the bleeding edge of what 3D printers are capable of, and this year is no exception. This year, we were graced with a few true multicolor filament-based 3D printers. The biggest and best comes from [Daren Schwenke] and the rest of the Arcus3D crew. This printer is a full color, CMYKW mixing printer that’s able to print in any color imaginable.

The extruder assembly, suspended from the top of the printer
The bizarre mixing hotend, powered by a brushless motor

The electronics for this printer are, to say the least, very weird. The controller board is BeagleBone Black plus a CRAMPS running Machinekit. The hotend is bizarre, feeding six PTFE tubes into a weird water-cooled assembly that mixes and squirts filament out of the nozzle with the help of a small brushless motor. Thanks to a clever design, the end effector of the hotend weighs only about 150 grams – about the same as any other delta printer out there – and this printer is able to move very fast.

Over the last year, we’ve seen a lot of improvements in the state of multi-material and multi-color extrusion for 3D printers. At last year’s Maker Faire NY, Prusa’s i3 quad extruder made an appearance alongside the ORD Solutions RoVa4D printer. These are two completely different approaches to multicolor 3D printing, with the RoVa mixing filament, and the Prusa merely extruding multiple colors. Both approaches have their merits, but mixing extruders are invariably harder to build and the software stack to produce good prints isn’t well-defined.

Even though we’re still in the early years of full-color filament-based printing, this is still an awesome result. In a few years, we’ll be able to look back on [Daren]’s efforts and see where our full-color 3D printers came from – open source efforts to create the best hardware possible.

[Daren] has been working on this printer for a while, and he’s been uploading all his project updates to hackaday.io. You can check out the build log here.

Oscillating Fan Controller Used As Relay

March 26, 2017 by 10 Comments

The most brilliant hacks we see aren’t always the thousand-dollar, multi-year projects spanning every facet of engineering. Rather, the most ingenious projects are ones that take an everyday thing and use it in a simple but revolutionary way. By that measure, it’ll be hard to top [Robert]’s latest hack which uses the controller board from an everyday oscillating fan to build a three-way remote-controlled relay board.

Most oscillating fans have a speed selector switch. What that does might be somewhat different between different types of fan, but in general it will select either a smaller portion of the fan’s motor to energize or switch in a resistor which will have the same speed-lowering effect. [Robert]’s fan had little more than a triple-throw switch on the control board, so when he decided the fan wasn’t worth keeping anymore, he was able to re-purpose the control board into a general-use relay. As a bonus, the fan could be controlled by infrared, so he can also remote control whatever he decides to plug into his new piece of equipment.

While this simple hack might not change the world, it may give anyone with an old fan some ideas for other uses for its parts. If you want to do a little more work and get the fan itself running again, though, it is possible to rebuild the whole thing from the ground up as well.

CNC Turns Empty Cans Into Action Figures

March 26, 2017 by 27 Comments

[apollocrowe] at Carbide 3D (a company that does desktop CNC machines) shared a project of his that spent years being not-quite-there, but recently got dusted off and carried past the finish line. His soda can robot action figures were originally made by gluing a paper design to aluminum from a soda can, but [apollocrowe] was never really able to cut the pieces as reliably or as accurately as he wanted and the idea got shelved. With a desktop CNC machine to take care of accurate cutting, the next issue was how to best hold down a thin piece of uneven metal during the process. His preferred solution is to stick the metal to an acrylic wasteboard with hot glue, zero high enough and cut deep enough to account for any unevenness, and afterwards release the hot glue bond with the help of some rubbing alcohol.

Assembly involves minor soldering and using a few spare resistors. A small spring (for example from a retractable pen) provides the legs with enough tension for the figure to stand by itself. The results look great, and are made entirely from a few cents worth of spare parts and recycled materials. A video of the process is embedded below, and the project page contains the design files.

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