In late 2013 and early 2014, in the heady days of the drone revolution, there was one killer app — the selfie drone. Selfie sticks themselves had already become a joke, but a selfie drone injected a breath of fresh air into the world of tech. Fidget spinners had yet to be invented, so this is really all we had. It wasn’t quite time for the age of the selfie drone, though, and the Lily camera drone — in spite of $40 Million in preorders — became the subject of lawsuits, and not fines from the FAA.
Technology marches ever forward, and now you can build your own selfie drone. That’s exactly what [geaxgx] did, although this build uses a an off-the-shelf drone with custom software instead of building everything from scratch.
For hardware, this is a Ryze Tello, a small, $100 quadcopter with a front-facing camera. With the right libraries, you can stream images to a computer and send flight commands back to the drone. Yes, all the processing for the selfie drone happens on a non-flying computer, because computer vision takes processing power and battery life.
The software comes from CMU’s OpenPose library, a real-time solution for detecting a body, face, or hands. With this, [geaxgx] was able to hover the drone and keep his face in the middle of the camera’s frame. While there’s no movement of the drone involved — the drone is just hovering and rotating to the left and right — it is a flying selfie stick without the stick. You can check out the video below and check out all the code on [geaxgx]’s GitHub here.
For a hundred years or thereabouts, if you made something out of plastic, you used a mold. Your part would come out of the mold with sprues and flash that had to be removed. Somewhere along the way, someone realized you could use these sprues to hold parts in a frame, and a while later the plastic model was invented. Brilliant. Fast forward a few decades and you have 3D printing. There’s still plastic waste in 3D printing, but it’s in the form of wasteful supports. What if someone designed a 3D printable object like a flat-pack plastic model? That’s what you get when you make a Fully 3D-printable wind up car, just as [Brian Brocken] did. It’s his entry for the Hackaday Prize this year, and it prints out as completely flat parts that snap together into a 3D model.
This 3D model is a fairly standard wind-up car with a plastic spring, escapement, and gear train to drive the rear wheels. Mechanically, there’s nothing too interesting here apart from some nice gears and wheels designed in Fusion 360. Where this build gets serious is how everything is placed on the printer. Every part is contained in one of two frames, laid out to resemble the panels of parts in a traditional plastic model.
These frames, or sprue trees, or whatever we’re calling this technique in the land of 3D printing, form a system of supports that keep all the parts contained until this kit is ready to be assembled. It’s effectively a 3D printable gift card, flat packed for your convenience and ease of shipping. A great project, and one that proves there’s still some innovation left in the world of 3D printing.
For whatever you have built, there is someone who has done it longer, and knows more about it. That is the basic premise of expertise, and for this year’s Hackaday Prize we’re rolling out with a series of mentor sessions. These are master classes that match up experts in product development with the people behind the projects in the Hackaday Prize. We’ve been recording all of these so everyone can benefit from the advice, guidance, and mentorship presented in these fantastic recordings.
The DrumKid, a random drum synthesizer
Mitch Altman is someone who should be very familiar to all Hackaday readers. He’s the inventor of the TV-B-Gone, that wonderful device that simultaneously turns you into a hero and a villain in any sports bar. He’s the President and CEO of Cornfield Electronics and co-founder of the Noisebridge hackerspace in San Francisco. Mitch is an author and teacher, and seems to be at just about every conference and workshop around the world promoting hackerspaces, Open Source hardware, and mentorship where ever he goes.
The first hardware creator to meet Mitch is Matt Bradshaw, creator of the DrumKid. This is a pocket-sized drum machine that is heavily inspired by Teenage Engineering’s Pocket Operators. Years ago, Matt built a web app that generated drum tracks, and this project is simply taking that idea into the physical realm. For Mitch, this is well-tread territory; years ago, Mitch also built an Arduino-based synth, and for the most part, both Mitch and Matt’s projects are remarkably similar. There were, however, some improvements to be made with Matt’s circuit. The power supply was two AAA batteries and a switching regulator that introduced noise and added cost. Mitch suggested that the ATMega328 could be run directly from three AA batteries reducing the cost and the noise.
eAgrar, a system for monitoring conditions of plants and weather conditions at agricultural fields
The next project up for review is eAgrar, a system for monitoring conditions of plants and the weather in fields. This project comes from Slaven Damjanovic and Marko Čalić. They’ve been developing this device for almost two years building the entire system around the ATMega328. Slaven ran into a problem with this chip in that he didn’t have enough inputs and outputs. The firmware is already written, but thanks to the Arduino IDE, there’s no reason to keep using that ATMega. Mitch suggested using an STM32 or another ARM core. That’s what he’s using for one of his synthesizer projects, and you get more than enough inputs and outputs for the same price as an ATMega.
Finally, we come to Joseph, with his project, the Pilates Reformer. A Pilates Reformer is a bit of exercise equipment that’s only made by three companies and everything costs thousands of dollars. Joseph is bringing that cost down, but there’s a problem: how do you build a hundred or two hundred of these? Mitch suggested simply finding another manufacturer that could build this design, and not necessarily one that builds Pilates machines. This makes sense — if all you’re doing is cutting and connecting structural beams, any manufacturer can do this, that’s what manufacturers do.
This is the third in our series of Hackaday Prize mentor sessions this year, and we have far more we need to edit, and many more we need to record. That doesn’t mean you can’t get help from experts from your prize entry; we’re looking for people who need help with their project and we have a lot of mentors willing to dispense advice. If you’re interested in having someone look over your shoulder, sign up your entry.
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.
In every workshop ever, there’s a power tool that goes unnoticed. It’s the bench grinder. It’s useful when you need it, and completely invisible when you don’t. We take the bench grinder for granted, in part because we keep it over there with that box of oily rags, and partly because it’s so unassuming.
But you can really mess your hands up on a bench grinder. Words like ‘degloving’ are thrown around, and that doesn’t involve actual gloves. For his Hackaday Prize entry, [Scott] is adding safety to the ubiquitous bench grinder. It’s called the Grinder Minder, and it aims to make the humble bench grinder a lot safer.
There are a few goals to the Grinder Minder, most importantly is DC injection braking. This stops the grinder from spinning, and if you’ve ever turned off a bench grinder and waited for it to spin down, you know there’s either a lot of energy in a grinder wheel. Grinder Minder also adds accidental restart protection and an actual ANSI-compliant emergency stop. All of this is designed so that’s it’s a direct drop-in electronics package for a standard off-the-shelf grinder.
The early prototypes for the Grinder Minder have the requisite MOSFETs and gigantic wire-wound resistors , but the team has recently hit an impasse. The current market research tells them the best way forward is designing a product for bigger, more powerful tools that use three-phase power. The team is currently researching what this means for their project, and we’re looking forward to seeing where that research lands them.
When designing a printed circuit board, there are certain rules. You should place decoupling capacitors near the power pins to each chip. Your ground planes should be one gigantic fill of copper; two ground planes connected by a single trace is better known as an antenna. Analog sections should be kept separate from digital sections, and if you’re dealing with high voltage, that section needs to be isolated.
One that I hear a lot is that you must never put a 90-degree angle on a trace. Some fear the mere sight of a 90-degree angle on a PCB tells everyone you don’t know what you’re doing. But is there is really no greater sin than a 90-degree trace on a circuit board?
This conventional wisdom of eschewing 90-degree traces is baked into everything we know about circuit board design. It is the first thing you’re taught, and it’s the first thing you’ll criticize when you find a board with 90-degree traces. Do square traces actually matter? The short answer is no, but there’s still a reason we don’t do it.
The last decade or so has seen remarkable advances in motor technology for robotics and hobby applications. We’re no longer stuck with crappy brushed motors, and now we have fancy (and cheap!) stepper motors, brushless motors for drones, and servo motors. This has led to some incredible achievements; drones are only barely possible with brushed motors, and you can’t build a robot without encoders.
For his entry into the Hackaday Prize, [Gabrael Levine] is taking on one of the hardest robotics challenges around: the bipedal robot. It’s a chickenwalker, or an AT-ST; either way, you need a lot of power in a very small space, and that’s where the OpenTorque Actuator comes in. It’s a quasi-direct-drive motor that was originally pioneered by the MIT Biomimetics Lab.
The key feature of the OpenTorque Actuator is using a big brushless motor, a rotation encoder, and a small, 8:1 planetary gear set. This allows the motor to be backdrivable, capable of force-sensing and open-loop control, and because this actuator is 3D printed, it’s really cheap to produce.
But a motor without a chassis is nothing, and that’s where the Blackbird Bipedal Robot comes in. In keeping with best practices of robotic design, the kinematics are first being tested in simulation, with the mechanical build happening in parallel. That means there’s some great videos of this chickenwalker strutting around (available below), and so far, everything looks great. This bipedal robot can turn, walk, yaw, and work is continuing on the efforts to get this bird-legged bot to stand still.
