Year: 2019

Custom Machined Pump Keeps CNC Lubrication Under Control

June 27, 2019 by 19 Comments

Rub two pieces of metal against each other hard enough, and it won’t be long before they heat up sufficiently to cause problems. That’s especially true when one is a workpiece and one is a tool edge, and the problems that arise from failing to manage the heat produced by friction can cost you dearly.

The traditional way of dealing with this is by pumping heavy streams of liquid coolant at the workpiece, but while that works, it creates problems of its own. That’s where minimum quantity lubrication comes in. MQL uses a fine mist of lubricant atomized in a stream of compressed air, which saves on lube and keeps swarf cleaner for easier recycling. The gear needed for MQL can be pricey though, so [brockard] decided to add homebrew MQL to his CNC router, with great results.

The video below shows the whole process, from raw metal to finished system – skip ahead to about 12 minutes if you just want to see final testing, but be warned that you’ll be missing some high-quality machining. The finished pump is a double-piston design, with each side driven by a cam rotated by a servo. An Arduino controls the speed of the motor based on the current settings; the pump is turned on and off through G-code control of a relay.

The lubricant stream is barely visible in the video, as opposed to the sloshing mess of traditional flood coolants, and seems much more suitable for a hobbyist-grade CNC setup. Need to build a CNC router before you build this? You can do much worse than this one.

Continue reading “Custom Machined Pump Keeps CNC Lubrication Under Control” →

Replacement Batteries For The Sony Discman

June 27, 2019 by 24 Comments

Some of the first Sony Discmans included rechargeable batteries. These batteries were nickel metal hydride batteries (because of the technology of the time) and are now well past their service life. The new hotness in battery technology is lithium — it offers greater power density, lighter weight, and a multitude of ready-to-go, off the shelf cells. What if someone were to create a new battery pack for an old Sony Discman using lithium cells? That’s exactly what [sjm4306] did for their entry into this year’s Hackaday Prize.

The Discman [sjm] is working with uses a custom, Sony-branded battery based on NiMH technology with a capacity of around 500 mAH. After carefully measuring the dimensions of this battery, it was replicated in plastic with a 3D printer. This enclosure was then stuffed with a small lithium cell scavenged from a USB power bank.

The only tripping points for this build were the battery contacts. The originally battery had two contacts on the end that fit the Discman exactly; these were replicated with a small PCB wired up to the guts of the USB powerbank. The end result is a direct, drop-in replacement for the original Discman battery with a higher capacity, that’s also rechargeable via USB. It’s a fantastic project, with the entire build video available below.

Continue reading “Replacement Batteries For The Sony Discman” →

Brett Smith Makes Your Life Easier With Hidden Microcontroller Features

June 27, 2019 by 37 Comments

There was a time when microprocessors were slow and expensive devices that needed piles of support chips to run, so engineers came up with ingenious tricks using extra hardware preprocessing inputs to avoid having to create more code. It would be common to find a few logic gates, a comparator, or even the ubiquitous 555 timer doing a little bit of work to take some load away from the computer, and engineers learned to use these components as a matter of course.

The nice thing is that many of these great hardware hacks have been built into modern microcontrollers through the years. The problem is you know to know about them. Brett Smith’s newly published Hackaday Superconference talk, “Why Do It The Hard Way?”, aims to demystify the helpful hardware lurking in microcontrollers.

Join us below for a deeper dive and the embedded video of this talk. Supercon is the Ultimate Hardware con — don’t miss your chance to attend this year, November 15-17 in Pasadena, CA.

Continue reading “Brett Smith Makes Your Life Easier With Hidden Microcontroller Features” →

Testing Brushless Motors With A Little Help From The ESC

June 27, 2019 by 6 Comments

These days, brushless motors are the go-to for applications requiring high power in a compact package. It’s possible to buy motors in all manner of different configurations off the shelf, and the range available is only getting better. However, sometimes getting something truly optimal requires a bit of customization. With motors, this can involve swapping magnets or hand-winding coils. In these cases, it can be useful to test the modified motor to determine its performance. [JyeSmith]’s ESC tester is capable of just that.

Fundamentally, the ESC tester is a simple piece of hardware. It uses a microcontroller to speak the Dshot protocol. This protocol is typically used to communicate between multi-rotor flight controllers and ESCs. In this case, the Dshot telemetry is instead displayed on a small OLED screen. This enables the user to read off KV values, as well as other useful data such as current draw and RPM. This can help quantify the effects of any modifications made to a motor, as well as prove useful for learning about parts of spurious origins.

It’s a device that should prove useful to those trying to eke out every last drop of performance from their multi-rotor builds. We expect to see more similar projects emerge as drone racing continues to increase in popularity. If you’re still trying to learn the theory behind the technology, you can always build your own brushless motor. Video after the break.

[Thanks to Keegan for the tip!]

Continue reading “Testing Brushless Motors With A Little Help From The ESC” →

Reverse Engineering Cyclic Redundancy Codes

June 27, 2019 by 17 Comments

Cyclic redundancy codes (CRC) are a type of checksum commonly used to detect errors in data transmission. For instance, every Ethernet packet that brought you the web page you’re reading now carried with it a frame check sequence that was calculated using a CRC algorithm. Any corrupted packets that failed the check were discarded, and the missing data was detected and re-sent by higher-level protocols. While Ethernet uses a particularly common CRC, there are many, many different possibilities. When you’re reverse-engineering a protocol that contains a CRC, although it’s not intended as a security mechanism, it can throw a wrench in your plans. Luckily, if you know the right tool, you can figure it out from just a few sample messages.

A case in point was discussed recently on the hackaday.io Hack Chat, where [Thomas Flayols] came for help reverse engineering the protocol for some RFID tags used for race timing. Let’s have a look at the CRC, how it is commonly used, and how you can reverse-engineer a protocol that includes one, using [Thomas’] application as an example.

Continue reading “Reverse Engineering Cyclic Redundancy Codes” →

The Digital Polaroid SX-70

June 27, 2019 by 15 Comments

What do you do if you own an iconic and unusual camera from decades past? Do you love it and cherish it, buy small quantities of its expensive remanufactured film and take arty photographs? Or do you rip it apart and remake it as a modern-day digital camera in a retro enclosure? If you’re [Joshua Gross], you do the latter.

The Polaroid SX-70 is an iconic emblem of 1970s consumer technology chic. A true design classic, it’s a single-lens reflex design using a Polaroid instant film cartridge, and its party trick is that it’s a folding camera which collapses down to roughly the size of a pack of 1970s cigars. It was an expensive luxury camera when it was launched in 1972, and today it commands high prices as a collector’s item.

[Joshua]’s build is therefore likely to cause weeping and wailing and gnashing of teeth among vintage camera enthusiasts, but what exactly has he done? In the first instance, he’s performed a teardown of the SX-70 which should be of interest to many readers in itself. He’s removed the mirror and lens, mounted a Raspberry Pi camera behind the lens mount, and a small LCD monitor where the mirror would be.

A new plastic lens in the original lens housing completes the optics, and the electronics come courtesy of a Pi Zero, battery, and USB hub in the space where the Polaroid film cartridge would otherwise be. Some new graphics and a fresh leather cover complete the  build, giving what we’d say is a very tidy electronic Polaroid. On the software side there is a filter to correct for fisheye distortion, and the final photos have a slightly Lomographic quality from the plastic lens.

We like what he’s created with his SX-70 even if we can’t help wincing that he did it to an SX-70 in the first place. Maybe it’s less controversial when someone gives the Pi treatment to a more mundane Polaroid camera.

LED Matrix Becomes Fun Tetris Clock

June 27, 2019 by 1 Comment

Sometimes a project is borne simply out of the fact that some interesting parts have been left sitting around too long. Of course, this is as good a reason to build as any other, and can often lead to some interesting results. [Jorj Bauer]’s Tetris Display is one such project.

The project started because [Jorj] had an 8 x 32 WS2812 LED array laying about, and it was high time it got turned into something cool. The resulting display has several features, making it a welcome piece around the home. It can act as a clock, with automatic compensation for daylight savings and brightness control depending on the time of day. It can also serve as a text scroller, and of course, the party piece – it can play Tetris. It all runs on an ESP-01, with a second device acting as a remote to control the game.

Rather than simply being another LED matrix project, [Jorj] put a little flair into things. A font was developed that allowed the time to be displayed in a pixel font composed entirely of Tetris pieces (or tetrominos). This allows the time to be displayed by pieces dropping from the top of the display. The Tetris implementation is solid, too – implementing the proper Super Rotation System that professionals would expect.

[Jorj] reports that this build was inspired by an earlier Tetris Clock featured in these very pages. It’s a tidy piece that we’re sure is a great addition to the mantlepiece. Video after the break. Continue reading “LED Matrix Becomes Fun Tetris Clock” →