Author: Donald Papp

1313 Articles

Whimsical Solder Stand Moonlights As Toy 3D Printer

September 15, 2020 by 12 Comments
A few Lego pieces provide key functionality, like an articulated dispenser head.

Most of us have bent a length of solder into a more convenient shape and angle when soldering, and just sort of pushed the soldering iron and work piece into the hanging solder instead of breaking out a third hand. Well, [yukseltemiz] seems to have decided that a solder dispenser and a miniature 3D printer model can have a lot in common, and created a 1/5 scale Ender 3 printer model that acts as a solder stand and dispenser. The solder spool hangs where the filament roll would go, and the solder itself is dispensed through the “print head”.

It’s cute, and we do like the way that [yukseltemiz] incorporated a few Lego pieces into the build. A swivel and eyelet guides the solder off the roll and a small Lego ball and socket gives the dispenser its articulation, an important feature for bending solder to a more convenient angle for working. It makes us think that using Lego pieces right alongside more traditional hardware like M3 nuts and bolts might be an under-explored technique. You can see the unit in action in the brief assembly video, embedded below.

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A Bit Of DIY Helps Cut Straight And Happy Threads

September 12, 2020 by 40 Comments
A cheap and effective ratcheting tap.

Need to cut threads into a hole? A tool called a tap is what you need, and a hand-operated one like the one shown here to the side is both economical and effective. A tap’s cutting bit works by going into a pre-drilled hole, and it’s important to keep the tool straight as it does so. It’s one thing to tap a few holes with steady hands and a finely calibrated eyeball, but when a large number of holes need to be tapped it can be worth getting a little help.

The usual tool to help keep a tap straight and pressed gently downwards is called a tap follower, but [Tony] had a lot of M4 holes to tap and no time to order one and wait for it to arrive. Instead, he converted a cheap tap into a tool that could be held in the chuck of his mill, with the freedom to slide up and down as needed. The result? A tap that’s hand-operated but certain to be orthogonal to the work piece, making the job of cutting a lot of threads much more pleasant.

Tapping isn’t just for metal, either. Cutting threads into wood is also done, and be sure to check out this simple method for making your own surprisingly effective wood taps in the shop with a threaded rod, or a lag screw. Of course, the need to tap a hole can be sidestepped by using threaded inserts in the right material, instead.

Cell Phone Signal Booster Gets Teardown And Demo

September 10, 2020 by 7 Comments

Ever wonder what was inside a cell phone booster, or what it is like to set up or use one? If so, [Kerry Wong]’s got you covered with his teardown of a Cel-Fi Go X Cell Signal Booster by Nextivity. [Kerry] isn’t just ripping apart a cheap unit for laughs; his house has very poor reception and this unit was a carefully-researched, genuine investment in better 4G connectivity.

The whole setup consists of three different pieces: the amplifier unit pictured above, and two antennas. One is an omnidirectional dome antenna for indoors, and the other is a directional log-periodic dipole array (LPDA) antenna for outdoors. Mobile phones connect to the indoor antenna, and the outdoor antenna connects to the distant cell tower. The amplifier unit uses a Bluetooth connection and an app on the mobile phone to manage settings and actively monitor the device, which works well but bizarrely doesn’t seem to employ any kind of password protection or access control whatsoever.

Overall [Kerry] is happy, and reports that his mobile phone enjoys a solid connection throughout his house, something that was simply not possible before. Watch a hands-on of the teardown along with a short demonstration in the video embedded below.

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3D-Printed Flight Controls Use Magnets For Enhanced Flight Simulator 2020 Experience

September 3, 2020 by 24 Comments

We have seen quite a few DIY joystick designs that use Hall effect sensors, but [Akaki Kuumeri]’s controller designs (YouTube video, embedded below) really make the most of 3D printing to avoid the need for any other type of fabrication. He’s been busy using them to enhance his Microsoft Flight Simulator 2020 experience, and shares not just his joystick design, but makes it a three-pack with designs for throttle and pedals as well.

Hall effect sensors output a voltage that varies in proportion to the presence of a magnetic field, which is typically provided by a nearby magnet. By mounting sensors and magnets in a way that varies the distance between them depending on how a control is moved, position can be sensed and communicated to a host computer.

In [Akaki]’s case, that communication is done with an Arduino Pro Micro (with ATmega32U4) whose built-in USB support allows it to be configured and recognized as a USB input device. The rest is just tweaking the physical layouts and getting spring or elastic tension right. You can see it all work in the video below.

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Retrocomputing Spray Paints: Amiga Beige, Commodore, And ATARI Grey

September 1, 2020 by 19 Comments

[retrohax] has provided vintage computer guidance for years, and part of that guidance is this: sometimes using paint as part of restoration is simply unavoidable. But the days of tediously color-matching to vintage hardware are gone, thanks to [retrohax] offering custom-mixed spray paints in Amiga 500 Beige, C-64 Beige, and ATARI ST/SE Grey. (At the moment only delivery within Poland is available due to shipping restrictions, but [retrohax] is working on a better solution.)

As a companion to making these vintage colors available, there is also a short how-to guide on how to properly prep and spray paint a computer case for best results that talks a little about the challenges in color matching to vintage hardware, and how getting custom paints mixed makes life much easier. Hackers may value making do with whatever is available, but we can also appreciate the value of having exactly the right material or tool for the job.

It’s not every day we see someone mixing custom spray paint colors, but off the shelf options don’t always cut it. Another example of getting specialty materials made from the ground up is custom plywood specifically designed for laser-cutting puzzles, something done because the troubles that came with off-the-shelf options were just not worth the hassle.

100% Printed Flashlight: Conductive Filament And Melted-in Leads

August 31, 2020 by 28 Comments

Conductive filament isn’t an ideal electrical conductor, but it’s a 3D-printable one and that’s what makes [Hercemer]’s 3D-printed flashlight using conductive filament work. Every part of the flashlight is printed except for the 9 volt battery and LEDs. Electrically speaking, the flashlight is a small number of LEDs connected in parallel to the terminals of the battery, and turning it on or off is done by twisting or loosening a cap to make or break the connection.

The main part of the build is a 3D-printed conductive cylinder surrounded by a printed conductive ring with an insulator between them. This disk- or pad-shaped assembly forms not only the electrical connection between the LEDs and battery terminals, but also physically holds the LEDs. To attach them, [Hercemer] simply melts them right in. He uses a soldering iron to heat up the leads, and presses them into the 3D-printed conductive block while hot. The 9 V battery’s terminals contact the bottom when the end cap is twisted, and when they touch the conductive assembly the flashlight turns on.

Anticipating everyone’s curiosity, [Hercemer] measured the resistance of his conductive block and measured roughly 350 ohms when printed at 90% infill; lower infills result in more resistance. You can see a video of the assembly and watch the flashlight in action in the video, embedded below.

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Grasp Kotlin’s Coroutines With This Short Tutorial

August 31, 2020 by 1 Comment

Kotlin is a relatively new programming language; a derivative of Java with lots of little handy functional bits such as coroutines. [Foalyy] is porting an app to Android and learning Kotlin at the same time, and after wrapping their mind around coroutines, has written up a concise five-part tutorial on them.

Coroutines in Kotlin are a way to simplify writing asynchronous code, which is code that doesn’t necessarily execute in the order it is written. Coroutines are like light-weight threads that can be launched and managed easily, making it simpler to bridge together blocking and non-blocking code. (However, coroutines are not threads. They are more akin to suspending functions that play very well together.)

[Foalyy] found that the official Kotlin documentation on coroutines went into great detail on how coroutines function, but wanted a more bottom-up approach to understanding how they work and can be used. Luckily for anyone who thinks the same way, [Foalyy] wrote it all up and begins with a great recap of important elements, but if you prefer you can jump straight to the examples.

Kotlin has been around for a while, and readers with sharp memories may recall it was featured in this excellent introduction to what neural networks are and how they work.