Portable Pi Power Pack Makes For Petite Projects

April 9, 2019 by 24 Comments

Since the Pi Zero was released, there have been many attempts to add a power bank. Cell phone batteries are about the same size as a Pi Zero, after all, and adding a USB charging port and soldering a few wires to a Pi is easy. The PiSugar is perhaps the cutest battery pack we’ve seen for the Pi Zero, and it comes in a variety of Hats compatible with the Pi, capable of becoming a small display, a keyboard, or any other thing where a small, portable Linux machine is useful.

The core of this build is a small circuit board the size of a Pi Zero. Attached to this board is a 900mAh battery, and the entire assembly is attached to the Pi Zero with a set of two spring clips that match up with with a pair of pads on the back of the Pi. Screw both of these boards together, and you have a perfect, cableless solution to adding power to a Pi Zero.

But the PiSugar doesn’t stop there. There are also cases, for a 1.3 inch LCD top, a 2.13 inch ePaper display, an OLED display, a camera, a 4G module, and something that just presents the pins from the Pi GPIO header. This is an entire platform, and if you print these parts in white plastic, they look like tiny little sugar cubes filled to the brim with electronics and Linux goodness.

Yes, you’ve seen 3D printed Pi cases before, but nothing in the way of an entire platform that gives you a Pi Zero in an extensible platform that can fit in your pocket and looks like sweet, sweet cubes of sucrose.

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Arduino Drives Seventeen Stepper Motors, Carefully

April 9, 2019 by 27 Comments

It’s fair to say that building electronic gadgets is easier now than it ever has been in the past. With low-cost modular components, there’s often just a couple dozen lines of code and a few jumper wires standing between your idea and a functioning prototype. Driving stepper motors is a perfect example: you can grab a cheap controller board, hook it up to a microcontroller, and the rest is essentially just software. But recently [mechatronicsguy] wondered if even that was more hardware than was technically necessary to get the job done.

It’s not that he was intentionally looking to make things more complicated for himself, of course. His rationale was entirely economic; if you’re looking to drive a dozen or more stepper motors, even the “cheap” controllers can add up. So he started to wonder if he could skip the controller entirely and connect the stepper motor directly to the digital pins of an Arduino. Generally speaking this is a bad idea, but if you’re careful and are willing to take the risk, [mechatronicsguy] is living proof it’s possible

So what’s the trick to running a whopping seventeen individual stepper motors directly from the digital pins of an Arduino Mega? Well, to start with you’re not going to be running the beefy NEMA 17 motors like you might find in a 3D printer. [mechatronicsguy] is using the diminutive (and dirt cheap) 28BYJ-48, a light duty stepper used in many consumer products. Even with this relatively tiny motor, you need to crack open the case and cut a trace on the PCB to switch it from unipolar to bipolar.

Beyond that, you need to be careful. [mechatronicsguy] reports he’s had success running as many as ten of them at once, but realistically the fewer operating simultaneously the better. This is actually made easier due to the relatively poor specs of the 28BYJ-48 motor; its huge eleven degree step size means its not really susceptible to the same kind of slippage you’d get on a NEMA 17 when powered down. This means you can cut power to all but the actively moving motor and be fairly sure they’ll all stay where you left them.

With as popular as the 28BYJ-48 stepper is, there are several projects this “quick and dirty” method of interfacing could potentially work with. This small “barn door” star tracker is an obvious example, but we’ve also seen some very nice robotic arms built with these low-cost motors which could benefit from the technique.

Wireless Controllers For Retro Gaming

April 8, 2019 by 5 Comments

There’s no limit to the amount of nostalgia that can be minted through various classic platforms such as the NES classic. The old titles are still extremely popular, and putting them in a modern package makes them even more accessible. On the other hand, if you still have the original hardware things can start getting fussy. With modern technology it’s possible to make some changes, though, as [PJ Allen] did by adding wireless capabilities to his Commodore 64.

Back when the system was still considered “modern”, [PJ] tried to build a wireless controller using DTMF over FM radio. He couldn’t get it to work exactly right and ended up shelving the project until the present day. Now, we have a lot more tools at our disposal than analog radio, so he pulled out an Arduino and a few Bluetooth modules. There’s a bit of finesse to getting the old hardware to behave with the modern equipment, though, but once [PJ] worked through the kinks he was able to play his classic games like Defender without the limitations of wired controllers.

The Commodore 64 was incredibly popular in the ’80s and early ’90s, and its legacy is still seen today. People are building brand new machines, building emulators for them, or upgrading their hardware.

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A Laser Cutting 101

April 8, 2019 by 22 Comments

If you’ve worked with a laser cutter before, you might not find much new in [Maker Design Lab’s] recent post about getting started. But if you haven’t, you’ll find a lot of practical advice and clean clear figures. The write up focuses on a tube-style laser cutter that uses a gas-filled tube and mirrors. Some cheap cutters use a diode, and many of the same tips will apply to those cutters.

You can probably guess that a laser cutter can cut like a CNC and also engrave where the cut doesn’t go all the way through. But it can also mark metals and other surfaces by using a marking solution. If you’ve done CNC or 3D printing, the process is similar, but there are a few unique things to know, like the use of the marking solution.

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Reproducing Vintage Plastic Parts In Top-Notch Quality

April 8, 2019 by 16 Comments

Plastic is a highly useful material, but one that can also be a pain as it ages. Owners of vintage equipment the world over are suffering, as knobs break off, bezels get cracked and parts warp, discolor and fail. Oftentimes, the strategy has been to rob good parts from other broken hardware and cross your fingers that the supply doesn’t dry up. [Eric Strebel] shows us that’s not the only solution – you can replicate vintage plastic parts yourself, with the right tools.

In the recording industry there’s simply no substitute for vintage gear, so a cottage industry has formed around keeping old hardware going. [Eric] was tasked with reproducing VU meter bezels for a classic Neve audio console, as replacement parts haven’t been produced since the 1970s.

The first step is to secure a good quality master for replication. An original bezel is removed, and polished up to remove scratches and blemishes from 40+ years of wear and tear. A silicone mold is then created in a plywood box. Lasercut parts are used to create the base, runner, and vents quickly and easily. The mold is then filled with resin to produce the final part. [Eric] demonstrates the whole process, using a clear silicone and dyed resin to make it more visible for the viewer.

Initial results were unfortunately poor, due to the silicone and hardener used. The parts were usable dimensionally, but had a hazy surface finish giving very poor optical qualities. This was rectified by returning to a known-good silicone compound, which was able to produce perfectly clear parts first time. Impressively, the only finishing required is to snap off the runner and vents. The part is then ready for installation. As a final piece of showmanship, [Eric] then ships the parts in a custom laser-engraved cardboard case. As they say, presentation is everything.

With modern equipment, reproducing vintage parts like knobs and emblems is easier than ever. Video after the break.

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Duck And Cover With This WiFi “Geiger Counter”

April 8, 2019 by 10 Comments

There’s perhaps no sound more recognizable than the frantic clicking of a Geiger counter. Not because this is some post-apocalyptic world in which everyone is personally acquainted with the operation of said devices, but because it’s such a common effect used in many movies, TV shows, and video games. If somebody hears that noise, even if it doesn’t really make sense in context, they know things are about to get serious.

Capitalizing on this phenomena, [Anton Haidai] has put together a quick hack which turns the ESP8266 into a “Geiger counter” for WiFi. Rather than detecting radiation, the gadget picks up on the strongest nearby WiFi signal and will start clicking in response to signal strength. As the signal gets stronger, so does the clicking. While primarily a novelty, it’s an interesting idea that could potentially be useful for things like fox hunting.

The hardware is really about as simple as it gets, just a basic buzzer attached to one of the digital pins on a NodeMCU development board. This project is more of a proof of concept, but if it were to be developed further it would be interesting to see the electronics placed into a 3D printed replica of one of the old Civil Defense Geiger counters. Perhaps even integrating an analog gauge that can bounce around in response to signal strength.

Software-wise there is the option of locking onto one single network SSID or allowing the device to find the strongest network in the area. Even if you’re not in the market for a chirping WiFi detector, the code is a good example of how you can detect signal RSSI and act on it accordingly; a neat trick which might come in handy in a future project.

If you’re more interested in the real thing, we’ve got plenty of DIY Geiger counters in the archive for you to check out. From diminutive builds that can be mounted to the top of a 9V battery to high-tech solid state versions with touch screen interfaces, you should have plenty of inspiration if you’re looking to kit yourself out before your next drive through the Chernobyl Exclusion Zone.

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Metal 3D Printing — A Dose Of Reality

April 8, 2019 by 19 Comments

We have no doubt that hundreds of times a day a hacker is watching a 3D printer spew hot plastic and fantasizes about being able to print directly using metal. While metal printers are more common than ever, they are still out of reach for most people printing as a hobby. But as Mr. Spock once observed: “…you may find that having is not so pleasing a thing after all as wanting. It is not logical, but it is often true.” However, metal 3D printing has its own unique set of challenges. Texas A&M recently produced a short video explaining some of the design issues that you’ll encounter trying to make practical metal prints on an SLS (Selective Laser Melting) printer. You can see the video below.

The description says “It is more challenging to ‘metal 3D print’ a part than most people think. We’ve noticed the same even with plastic printers as friends will expect us to print the most outlandish things for them. What we like about this video is it helps to set expectations of the current state of the art so we’re not expecting far more than today’s metal printers can produce.

Among the features covered in the video are overhangs, which require supports. After removal, the surface is about like 80 grit sandpaper unless you perform further finishing. Just like plastic parts, warping and curling of large areas is a problem with metal. If you’ve ever been frustrated removing plastic support material, try having to ceramic grind metal supports off. They also use an EDM machine to cut especially tough supports, but it causes a lot of effort since it is likely to run through EDM wires and clog the filters.

We looked at recent advances in metal printing last year. We’ve seen homebrew machines that were little more than welders under computer control and we’ve seen plans by big players like HP to create metal prints, but at a steep price. Still, you can’t stop the march of 3D printing progress.

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