While it’s great to be experienced and have a ton of specialist knowledge needed to solve a problem, there’s something liberating about coming at things from a position of ignorance. Starting at ground zero can lead you down the path less traveled, and reveal solutions that might otherwise not have presented themselves. And, if [Robin Debreuil]’s exploration of the “minimum viable quadcopter” is any example, some pretty fun failure modes too.
The minimum viable product concept is nothing new of course, being a core concept in Lean methodologies and a common practice in many different industries. The idea of building an MVP is to get something working and in the hands of users, who will then give you feedback on everything wrong with it, plus, if you’re lucky, what you got right. That feedback informs the next design, which leads to more feedback and a whole iterative process that should design the perfect widget.
In [Robin]’s case, he wanted to build a quadcopter, but didn’t know where to start. So his first version was as simple as possible: a motor with a propellor and a small LiPo battery. No chassis, no control electronics — nothing. And it worked just about as well as expected. But fixing that problem led to different designs, the process of which was fascinating — we especially liked the quad with opposing motors controlled by mercury tilt switches to sense attitude changes.
In the end, [Robin] took a more conventional tack and used a microcontroller and BetaFlight to get his popsicle stick and hot glue UAV airborne. But the decision to start with a minimum viable design and iterate from there was a powerful learning experience in tune with [Robin]’s off-beat and low-key outlook, which we’ve seen before with his use of bismuth for desoldering and his scratch-off PCBs.
There’s something thrilling about decoding an unknown communications protocol. You start with a few clues, poke at the problem with some simple tools, and eventually work your way up to that first breakthrough that lets you crack the code. It can be frustrating, but when you eventually win, it can be very rewarding.
It seems that [Jason] learned this while decoding the wireless conversation between his mass-market quad and its controller. The quad in question, a Yuneec Q500, is one of those mid-range, ready-to-fly drones that’s targeted at those looking to get in the air easily and take some cool pictures. Unsure how the drone and controller were talking, [Jason] popped the covers and found a Zigbee chipset within. With the help of a $14 Zigbee USB dongle and some packet sniffing software from TI, [Jason] was able to see packets flowing, but decoding them was laborious. Luckily, the sniffer app can be set up to stream packets to another device, so [Jason] wrote a program to receive and display packets. He used that to completely characterize each controller input and the data coming back from the drone. It’s a long and strange toolchain, but the upshot is that he’s now able to create KML in real time and track the drone on Google Earth as it flies. The video below shows the build and a few backyard test flights.
Sometimes a project takes longer than it should to land in the Hackaday in-tray, but when we read about it there’s such gold to be found that it’s worth sharing with you our readers despite its slight lack of freshness. So it is with [Andrew Back]’s refurbishment of his Quad electrostatic speaker system power supply, it may have been published back in August but the glimpse it gives us into these legendary audio components is fascinating.
An electrostatic speaker is in effect a capacitor with a very large surface area, of which one plate is a flexible membrane suspended between two pieces of acoustically transparent mesh that form the other plates. A very high DC bias voltage in the multiple kilovolts region is applied across the capacitor, and the audio is superimposed upon it at a peak-to-peak voltage of somewhere under a kilovolt through a step-up transformer from the audio amplifier. There are some refinements such as that the audio is fed as a push-pull signal to the opposing mesh plates and that there are bass and treble panels with different thickness membranes, but these speakers are otherwise surprisingly simple devices.
The problem with [Andrew]’s speakers became apparent when he took a high voltage probe to them, one speaker delivered 3 kV from its power supply while the other delivered only 1 kV. Each supply took the form of a mains transformer and a voltage multiplier board, so from there it became a case of replacing the aged diodes and capacitors with modern equivalents before applying an insulating layer for safety.
Some legged robots end up moving with ponderous deliberation, or wavering in unstable-looking jerks. A few unfortunates manage to do both at once. [MusaW]’s 3D Printed Quadruped Robot, on the other hand, moves in rapid motions that manage to look sharp and insect-like instead of unstable. Based on an earlier design he made for a 3D printable quadruped frame, [MusaW] has now released this step-by-step guide for building your own version. All that’s needed is the STL files and roughly $50 in parts from the usual Chinese resellers to have the makings of a great weekend project.
The robot uses twelve SG90 servos and an Arduino nano with a servo driver board to control them all, but there’s one additional feature: Wi-Fi control is provided thanks to a Wemos D1 Mini (which uses an ESP-8266EX) acting as a wireless access point to serve up a simple web interface through which the robot can be controlled with any web browser.
Embedded below is a brief video. The first half is assembly, and the second half demonstrates the robot’s fast, sharp movements.
The massive engineering-defying Helicarrier from the Avengers is a brilliant work of CGI. Too bad it’d never actually fly… Like… Never.
Luckily, that didn’t stop our favorite RC hackers over at FliteTest from making a scale model of it — that actually works! If you’re not familiar, the Helicarrier is a fictional ship, the pride of S.H.I.E.L.D’s air force, or is it their navy.
It’s a massive aircraft carrier with four huge repulsor engines built into it, borrowing tech from Stark Industries. The shear size of it is what makes it completely ridiculous, but at the same time, it’s also unbelievably awesome.
Unfortunately, repulsor technology doesn’t seem to exist yet, so the FliteTest crew had to settle with a set of 8 brushless outrunner motors, with two per “engine”. The whole thing is almost 6′ long.
Now here’s a really cool engineering degree project — a team of students from a university in Vienna have made a pneumatically driven motor — and fitted it into a quad! (Translated)
The team consists of [Simon Friesacher], [Simon Schedl], [Christoph Sieber] and [Manuel Streith] who all happen to be in the same class as [Maximilian] and [Sebastian] the duo who brought us the VoLumen display, and [Max’s] Ripper CNC!
For their main project, the goal was to create an alternative and innovative motor — one that runs off of compressed air, using firefighter’s air tanks. Once they had that figured out, they decided to have some fun with it and put together the Air Quad. It only has a range of a few kilometers, and doesn’t perform quite as well its original gasoline counterpart, but we have to admit, it’s a very slick proof of concept!
Stick around after the break to see a promotional demo of the Air Quad in action!
After three huge mutant vehicle builds, [Tom Wilson] thought: “why not build another?” This time he decided to weld together a (comparatively) smaller more agile two-seater he calls the Boxer. We covered [Tom]’s previous quadbike, Big Dog, which features a similar tube frame, full suspension, and the familiar culvert pipe wheels. This time around [Tom] actually built an extensive jig out of plywood to ease in the build process. The Boxer is much lighter than its predecessor, weighing in at 125lbs Vs the Big Dog’s 490lbs, and about four feet shorter. The shorter lighter vehicle makes for a much more agile ride. If you are interested in building your own quadbike [Tom]’s site is a really good resource with tons of detail.
We really look forward to seeing this latest creation at burning man, check out a video of the (comparatively speedy) Boxer in action after the jump!