DIY Tiny Dovetail Cube Needs DIY Dovetail Cutter

October 10, 2019 by Donald Papp 4 Comments

Dovetail cutter, made from a 5 mm drill rod.

There’s a trinket called a dovetail cube, and [mitxela] thought it would make a fine birthday present. As you can see from the image, he was successful in creating a tiny version out of aluminum and brass. That’s not to say there weren’t challenges in the process, and doing it [mitxela] style means:

Make it tiny! 15 mm sides ought to do it.
Don’t have a tiny dovetail bit on hand, so make that as well.
Of course, do it all without CNC in free-machining style.
Whoops the brass stock is smaller than expected, so find a clever solution.
That birthday? It’s tomorrow, by the way.

The project was a success, and a few small learning experiences presented themselves. One is that the shape of a dovetail plays tricks on the human eye. Geometrically speaking, the two halves are even but it seems as though one side is slightly larger than the other. [mitxela] says that if he were to do it again, he’d make the aluminum side slightly larger to compensate for this visual effect. Also, deburring with a knife edge on such a small piece flattened the edges ever so slightly, causing the fit to appear less precise than it actually is.

Still, it was a success and a learning experience. Need more evidence that [mitxela] thrives on challenge? Take a look at his incredible vector game console project.

Hacking The IKEA TRÅDFRI LED Power Supply

October 8, 2019 by Donald Papp 22 Comments

Just because something is being actively documented and tampered with by enthusiastic hackers doesn’t mean the information is handily centralized. There can be a lot of value in gathering disparate resources in one place, and that’s exactly what [Trammell Hudson] has done with his resource page for hacking the IKEA TRÅDFRI LED power supply with wireless interface. Schematic teardown, custom firmware images, it’s all there in one convenient spot.

Back in 2017, the IKEA TRÅDFRI hacking scene was centered around the LED light bulbs but as the group of products expanded, the rest of the offerings have also gotten some attention.

Why bother tampering with these units? One reason is to add features, but another is to make them communicate over your own MQTT network. And MQTT is the reason you are only a Raspberry Pi and a trip to IKEA away from the beginnings of a smart home that is under no one’s control or influence but your own.

Pistol Safe’s Poor Design Means Biometric Sensor Bypassed In Seconds

October 3, 2019 by Donald Papp 38 Comments

When it comes to safes, mechanical design and physical layout are just as important as the electronic bits. If care isn’t taken, one element can undermine the other. That appears to be the case with this Amazon Basics branded biometric pistol safe. Because of the mechanical design, the fingerprint sensor can be overridden with nothing more than a thin piece of metal — no melted gummi bears and fingerprint impressions involved.

push button to reset safe fingerprint reader — Small button used to register a new fingerprint. It can be reached by inserting a thin shim in the gap between the door and the frame while the safe is closed and locked.

[LockPickingLawyer] has a reputation for exposing the lunacy of poorly-designed locks of all kinds and begins this short video (embedded below) by stating that when attempting to bypass the security of a device like this, he would normally focus on the mechanical lock. But in this case, it’s far more straightforward to simply subvert the fingerprint registration.

This is how it works: the back of the front panel (which is inside the safe) has a small button. When this button is pressed, the device will be instructed to register a new fingerprint. The security of that system depends on this button being inaccessible while the safe is closed. Unfortunately it’s placed poorly and all it takes is a thin piece of metal slid through the thin opening between the door and the rest of the safe. One press, and the (closed) safe is instructed to register and trust a new fingerprint. After that, the safe can be opened in the usual way.

It’s possible that a pistol being present in the safe might get in the way of inserting a metal shim to hit the button, but it doesn’t look like it. A metal lip in the frame, or recessing the reset button could prevent this attack. The sensor could also be instructed to reject reprogramming while the door is closed. In any case, this is a great demonstration of how design elements can affect one another, and have a security impact in the process.

As for fooling sensors in a more traditional sense, here’s a reminder that we’ve seen a 3D printer and a photo of a fingerprint used to defeat a fingerprint sensor.

Continue reading “Pistol Safe’s Poor Design Means Biometric Sensor Bypassed In Seconds” →

When Does Moving To Resin 3D Printing Make Sense?

October 2, 2019 by Donald Papp 50 Comments

An Elegoo Mars resin 3D printer, straight to my doorstep for a few hundred bucks. What a time to be alive.

Resin-based 3D printers using digital light processing (DLP) and especially stereolithography (SLA) are getting more common and much more affordable. Prosumer-level options like Formlabs and the Prusa SL1 exist, but more economical printers like the Elegoo Mars, Anycubic Photon, and more can be had for a few hundred bucks. Many printers and resin types can even be ordered directly from Amazon, right at this moment.

Resin prints can look fantastic, so when does it make sense to move to one of these cheap resin printers? To know that, consider the following things:

The printing process and output of resin printers is not the same as for filament-based printers. Design considerations, pre-processing, and post-processing are very different.
Resin printing has a different workflow, with consumables and hidden costs beyond the price of resin refills.

Things may not be quite where fused deposition modeling (FDM) printers were just a few short years ago when we were extremely impressed with the quality of printer one could get for about $200, but it is undoubtedly far more accessible than ever before. Let’s look at how to inform a decision about whether to take the plunge. Continue reading “When Does Moving To Resin 3D Printing Make Sense?” →

DIY Thermal Imager Uses DIY Gaussian Blur

September 29, 2019 by Donald Papp 18 Comments

Under the right circumstances, Gaussian blurring can make an image seem more clearly defined. [DZL] demonstrates exactly this with a lightweight and compact Gaussian interpolation routine to make the low-resolution thermal sensor data display much better on a small OLED.

[DZL] used an MLX90640 sensor to create a DIY thermal imager with a small OLED display, but since the sensor is relatively low-resolution at 32×24, displaying the data directly looks awfully blocky. Gaussian interpolation to improve the display looks really good, but it turns out that the full Gaussian interpolation isn’t a trivial calculation write on your own. Since [DZL] wanted to implement it on a microcontroller, the lightweight implementation was born. The project page walks through the details of Gaussian interpolation and how some effective shortcuts were made, so be sure to give it a look.

The MLX90640 sensor also makes an appearance in the Open Thermal Camera, one of the entries for the 2019 Hackaday Prize. If you’re interested in thermal imaging, don’t miss this teardown of a thermal imaging camera.

3D Printing Is Transformative Experience For Airgun Shooter

September 28, 2019 by Donald Papp 5 Comments

It’s interesting to peek into other scenes and niches and see how they intersect with things that one may find commonplace, like 3D printing. In this case, [NewToOldGuns] wrote a guest blog post for PyramydAir (a retailer, so be prepared for a lot of product links) about how 3D printing has completely transformed the experience of how he uses one of his favorite airguns, and allowed him to make changes and improvements that would not otherwise have been practical.

Not only are the 3D printed improvements thoughtful and useful, but it’s interesting to see familiar insights into the whole design process. After explaining some 3D printing basics, he points out that rapid iteration is key to effective prototyping, and a 3D printer can allow that to happen in a way not previously possible.

The pellets held inside the silver cylinder can no longer fall out, and the orange holder allows it to be simply pushed straight through into the gun’s receiver.

It all started with the small magazine which holds the rifle’s projectiles. It would be really handy to pre-load these for easier reloading, but there were practical problems preventing this. For one thing, there’s nothing to really hold the pellets in place and keep them from just falling out when it’s not loaded into the gun. Also, loading them into the gun without letting anything fall out was awkward at best. The solution was to design a simple holder that would cradle the magazine and cover the front and back to keep everything in place. [NewToOldGuns] also designed it so that it could mate directly to the gun, so the magazine could simply be pushed straight into the receiver while the action was held open.

Once this simple part was working, the floodgates of creativity were opened. Next was a belt attachment to hold multiple reloads, followed by a decision to mount the reloads directly onto the gun instead. An improved lever and sights quickly followed.

I also demonstrated the iterative approach to prototyping when I designed a simple alarm to detect when my 3D printer’s filament had run out. [NewToOldGuns] observes that the real power of 3D printing isn’t being able to make bottle openers or coat hooks on demand. It’s the ability to imagine a solution, then have that solution in hand in record time.

Tinker Pilot Project Cranks Cockpit Immersion To 11

September 25, 2019 by Donald Papp 1 Comment

One of the more interesting ideas being experimented with in VR is 1:1 mapping of virtual and real-world objects, so that virtual representations can have physically interaction in a normal way. Tinker Pilot is a VR spaceship simulator project by [LLUÍS and JAVI] that takes this idea and runs with it, aiming for the ability to map a cockpit’s joysticks, switches, and other hardware to real-world representations. What does that mean? It means a virtual cockpit with flight sticks, levers, and switches that have working physical versions that actually exist exactly where they appear to be.

A few things about the project design caught our eye. One is the serial communications protocol intended to interface easily with microcontrollers, allowing for feedback between the program and any custom peripherals. (By the way, this is the same approach Kerbal Space Program took with KSPSerialIO, which enables custom mission control hardware at whatever level of complexity a user may wish to implement.)

The possibilities are demonstrated starting around 1:09 in the teaser trailer (embedded below) in which a custom controller is drawn up in CAD, then 3D-printed and attached to an Arduino, and finally the 3D model is imported into the cockpit as a 1:1 representation of the actual working unit, with visual positional feedback.

Unlike this chair experiment we saw which attached a Vive Tracker to a chair, there is no indication of needing positional trackers on individual controls in Tinker Pilot. In a cockpit layout, controls can be reasonably expected to remain in fixed positions relative to the cockpit, meaning that they can be set up as 1:1 representations of a physical layout and otherwise left alone. The kind of experimentation that is available today even to individual developers or small teams is remarkable, and it’s fascinating to see the ideas being given some experimentation.

Continue reading “Tinker Pilot Project Cranks Cockpit Immersion To 11” →