After ordering replacement controller PCBs designed by [Adam] (assembled by your PCBA service of choice), you disassemble the servo, carefully setting the gearbox aside for now. Gutting the stock control board is the obvious next step, but from there, you don’t just drop the new PCB in – there’s more to getting a perfect servo than this, you have to add extra sensing, too. First, you have to print a spacer and a cover for the control board, as well as a new base for the motor. You also have to print (or perhaps, laser-cut) two flat encoder disks, one black and one white, the white one being eccentric. It only escalates from here!
Sometimes a great hack is great for no other reason than that it’s fun, and [Michael Rechtin]’s DIY Active Aero Spoiler and Air Brake certainly qualifies as a fun hack. This is a mod designed to live in a world where looks are everything, stickers add horsepower, and a good sound system is more important than good wheel alignment. Why is that? Because like the switch that exists only to activate the mechanism that turns it off, the DIY Active Aero Spoiler and Air Brake seen below is almost completely useless. So to understand its allure, we must understand its inspiration.
For a few decades now, luxury sports car manufacturers have been adding active aerodynamic components to their vehicles. For example, several Porsche models feature adaptive spoilers that adjust to driving conditions. Super cars such as the Bugatti Veyron have spoilers that flip up at high angles during braking to increase drag and reduce braking distance. All of these features are sadly missing from the average two or four door family-car-turned-wannabe-track-fiend. Until now!
[Michael] has created a new active spoiler for every mall-bound muffler-challenged hand me down. The build starts with a CNC cut foam wing which is covered with fiberglass, Bondo (an automotive necessity) and some faux carbon fiber for that go-fast feel. An Arduino, IMU, two servos, and a battery pack detect deceleration and automatically increase the spoiler angle just like the big boys, but without needing any integration into the vehicles systems. Or bolts, for that matter.
It’s unlikely that the braking force is enough to slow down the vehicle though, given that it’s not enough to pop the suction cups holding it to the trunk lid. But does it have the “wow” factor that it was designed to induce? Spoiler Alert: It does!
The ability to quickly create complex parts with 3D printers has created a platform to show off mechanical design skills. This is true in the case of [Dejan Ristic]’s capable little Tardygrade walking robot, which uses only two servos and a bunch of clever 3D printed parts.
The robot’s chassis is split into two subassemblies, each with a pair of feet on diagonal corners. As one pair of feet lifts the robot, the other section of the robot can rotate before coming back down, allowing the robot to turn. One servo handles the actuation of the feet, while the other rotates the body as required. An ESP32 based controller creates a web server user interface, and power comes from a lipo cell.
The interesting part of this robot is in how [Dejan] designed it for printing and assembly. All the parts can print without support, and in the correct orientation to optimize strength. There are only six screws in the assembly holding the servo and servo horns, while everything else uses snap fits or short pieces of filament. Take a look at the videos after the break to gain some appreciation of the design effort and attention to detail that went into this robot. Even the contact surfaces of the feet were carefully designed for optimum walking over flat surfaces and small obstacles.
Flip dots displays are timeless classics, but driving the large ones can quickly turn into a major challenge. The electromagnets require a lot of current to operate, and the driver circuits can get quite expensive. [James Bruton] wanted to build his own, but followed a bit of a different route, building a mechanically multiplexed flip dot (ball?) display.
Each of the dots on [James]’ 5×3 proof of concept is a bistable mechanical mechanism that can either show or hide a ping pong ball sized half sphere. Instead of using electromagnets, the dots are flipped by a row of micro servos mounted on a moving carriage behind the display. The mechanism is derived from one of [James]’ previous projects, a mechanical multiplexer. Each dot mechanism has a hook at the back of the mechanism for a servo to push or pull to flip the dot. A major disadvantage of this design is the fact that the servo horn must match the state of the dot before moving through the hook, otherwise it can crash and break something, which also reduces the speed at which the carriage can move.
This build was just to get a feel for the concept, and [James] already has several ideas for changes and improvements. The hook design can certainly change, and a belt drive would really speed things up. We think this mechanical display is a very interesting design challenge, and we are interested to hear how our readers would tackle it? Let us know in the comments below.
There are few things as frustrating when you’re trying to get some serious hacking done than intruders repeatedly showing up without permission. [All Parts Combined] has the solution for you, with a Kinect-based robotic sentry turret to keep them at bay.
The system consists of a Microsoft Kinect V2 connected to a PC, which runs an app to do all the processing, and outputs the targeting information to an Arduino over serial. The Arduino controls a simple 2-axis servo mount with an electric airsoft gun zip-tied to it. The trigger switch is replaced with a relay, also connected to the Arduino.
The Kinect V2 comes with SDKs that really simplify tracking human movement, and outputs the data in an easy-to-use format. [All Parts Combined] used the SDK in Unity, which allows him to choose which body parts to track. He added scripts that detect a few basic gestures, issues voice commands, and generates the serial commands for the Arduino. The servo angles are calculated with simple geometry, using XY coordinates of the target received from the SDK, and the known distance between the Kinect and turret. When an intruder enters the Kinect’s field of view it immediately starts aiming at the intruder’s heart, issues a “Hands Up!” command, and tells the intruder to leave. If the intruder doesn’t comply, it starts an audible countdown before firing. [All Parts Combined] also added a secret disarming gesture (double hand pistols), which turns the turret into an apologetic comrade. All it needs is a Portal-inspired enclosure.
It’s a fun project that illustrates how the Kinect can make complex computer vision tasks relatively simple. Unfortunately the V2 is no longer in production, having been replaced by the more expensive, developer focused Azure Kinect. We’ve covered several Kinect-based projects, including a 3D room scanner and a robotic basketball hoop.
[Adam]’s first robot arm build was a major disappointment, when the servos he had purchased for the build turned out to be terrible at holding an angle. With limited funds, he elected to improve on what he had, learning much about precision control techniques along the way. [Adam] taught himself how to implement industrial strength control loops using hobby hardware, by implementing additional encoders into servos and taking into account velocity and torque in addition to just position. With a magnetic encoder on the servo output shaft and a tiny optical encoder hand-built for inside the motor itself, much higher accuracy is achievable by allowing the control system to compensate for backlash.
If you’ve been following the Boston Dynamics project Spot, you’ve seen its capabilities and how we’re starting to see it being used in public more since its official release last year. But in a true display of how hobbyist electronics have been evolving and catching up with the big companies over the past few years, [Miguel Ayuso Parrilla] shows us his own take on the walking robot with CHOP, one of the finalists in this year’s Hackaday Prize.
Running the show are two main components, a Raspberry Pi 4B and an Arduino Mega. While the Mega interfaces with the servo controllers and provides filtering for sensors like the inertial measurement unit, the Pi takes all that data in and uses a series of Python scripts in order to determine the gait of the robot and which way the servos should move through an inverse kinematics model. To control the direction in which the body of the robot should accelerate, a Bluetooth remote controller sends commands to the Raspberry Pi.
We’re excited to see home-grown projects rise to this level of complexity, which would be mostly unheard of a few years ago in the maker scene, and only presented by large tech companies with tons of money to spend on research and development. There are other quadruped robots to inspire yourself on than Spot though, like this one with a spherical design and fold-out legs. Check this one in action after the break.