We’re all familiar with the experience of buying hobby servos. The market is awash with cheap clones which have inflated specs and poor performance. Even branded servos often fail to deliver, and sometimes you just can’t get the required torque or speed from the small form factor of the typical hobby servo.
Enter [James Bruton] and his DIY RC servo from a windscreen wiper motor. Windscreen wiper motors are cheap as chips, and a classic salvage. The motor shaft is connected to a potentiometer via a pulley and some string, providing the necessary closed-loop feedback. Instead of using the traditional analog circuitry found inside a servo, an Arduino provides the brains. This means PID control can be implemented on the ‘duino, and tuned to get the best response from different load characteristics. There’s also the choice of different interfacing options: though [James]’ Arduino code accepts PWM signals for a drop-in R/C servo replacement, the addition of a microcontroller means many other input signal types and protocols are available. In fact, we recently wrote about serial bus servos and their numerous advantages.
We particularly love this because of the price barrier of industrial servomotors; sure, this kind of solution doesn’t have the precision or torque that off-the-shelf products provide, but would be sufficient for many hacks. Incidentally, this is what inspired one of our favourite open source projects: ODrive, which focuses on harnessing the power of cheap brushless motors for industrial use.
Continue reading “Supersize DIY R/C Servos From Windscreen Wipers”
Clock movements are beautifully complex things. Made up of gears and springs, they’re designed to tick away and keep accurate time. Unfortunately, due to the vagaries of the universe, various sources of error tend to creep in – things like temperature changes, mechanical shocks, and so on. In the quest for ever better timekeeping, watchmakers decided to try and rotate the entire escapement and balance wheel to counteract the changing effect of gravity as the watch changed position in regular use.
They’re mechanical works of art, to be sure, and until recently, reserved for only the finest and most luxurious timepieces. As always, times change, and tourbillions are coming down in price thanks to efforts by Chinese manufacturers entering the market with lower-cost devices. But hey – you can always just make one at home.
That’s right – it’s a 3D printed gyrotourbillion! Complete with a 3D printed watch spring, it’s an amazing piece of engineering that would look truly impressive astride any desk. All that’s required to produce it is a capable 3D printer and some off-the-shelf bearings and you’ve got a horological work of art.
It’s not the first 3D-printed tourbillion we’ve seen, but we always find such intricate builds to be highly impressive. We can’t wait to see what comes next – if you’re building one on Stone Henge scale for Burning Man, be sure to let us know. Video after the break.
[Thanks to Keith for the tip!]
Continue reading “Gyrotourbillion Blesses The Eyes, Hard to Say”
Connecting your shiny new ESP8266 to WiFi can be as simple or as complicated as you please. Most people decide to manually add it. Some people find clever ways to make the bloody thing connect itself. [Eduardo Zola] transfers his WiFi password using the flashing light of a smartphone screen.
A simple photo-resistor and a bit of tinkering allows him to easily send credentials — or any data really — to his ESP8266, through the power of LiFi. Short for Light Fidelity, LiFi transmits data using light with on and off states representing digital values. It can use visible light, or reach into either the ultraviolet or infra-red radiation if need be. For the nitty-gritty details on the subject, check out our primer on LiFi.
A flashing LCD screen and a photo-resistor barely make the cut for a one-way LiFi system, but [Eduardo Zola] makes it work. The approach is to build a resitor divider and watch an input pin on the ESP for changes.
The trick is to keep ambient light out of the mix. The test sensor shown here places the LDR in a black cap, but [Eduardo] 3D-Printed a slick little enclosure for his reverse flashlight so it fits flush with the phone screen. One click and about half a minute of a flashing screen later, and the Wi-Fi credentials are transferred. This circuit could really be added onto any project, for short data transfers. With a bit more work on the sensor circuit, speed could be improved with the limiting factor being the timing on the phone screen itself.
Since the ESP8266 has its own WiFi connection, it’s likely you’ll use that for data transfer once the LiFi gets it onto the network. But any situation where you don’t have a full user input or a network connection could benefit from this. Pull out that old scrolling LED matrix project and add this as a way to push new messages to the device!
Continue reading “ESP8266 Uses LiFi To Get On WiFi”
Mini indoor drones have become an incredibly popular gift in the last few years since they’re both cool and inexpensive. For a while they’re great fun to fly around, until the inevitable collision with a wall, piece of furniture, or family member. Often not the most structurally sound of products, a slightly damaged quad can easily be confined to a cupboard for the rest of its life. But [Peter Sripol] has an idea for re-using the electronics from a mangled quad by building his own RC controlled paper aeroplane.
[Peter] uses the two rear motors from a mini quadcopter to provide the thrust for the aeroplane. The key is to remove the motors from the frame and mount them at 90 degrees to their original orientation so that they’re now facing forwards. This allows the drone’s gyro to remain facing upwards in its usual orientation, and keep the plane pointing forwards.
The reason this works is down to how drones yaw: because half of the motors spin the opposite direction to the other half, yaw is induced by increasing the speed of all motors spinning in one direction, mismatching the aerodynamic torques and rotating the drone. In the case of the mini quadcopter, each of the two rear motors spin in different directions. Therefore, when the paper plane begins to yaw off-centre, the flight controller increases power to the appropriate motor.
Mounting the flight controller and motors to the paper plane can either be achieved using a 3D-printed mount [Peter] created, or small piece of foam. Shown here is the foam design that mounts the propellers at wing level but the 3D printed version has then under the fuselage and flies a bit better.
Making paper planes too much effort? You could always use the one-stroke paper plane folder, or even the paper plane machine gun.
Continue reading “RC Paper Airplane From Guts Of Quadcopter”
For his Hackaday prize entry, [Daren Schwenke] is creating an open-source pick-and-place head for a 3D printer which, is itself, mostly 3D printable. Some serious elbow grease has gone into the design of this, and it shows.
The really neat part of this project comes in the imaging of the part being placed. The aim is to image the part whilst it’s being moved, using a series of mirrors which swing out beneath the head. A Raspberry Pi camera is used to grab the photos, an LED halo provides consistent lighting, and whilst it looks like OpenPnP may have to be modified slightly to make this work, it will certainly be impressive to see.
Two 9g hobby servos are used: one to swing out the mirrors (taking 0.19 seconds) and one to rotate the part to the correct orientation (geared 2:1 to allow 360 degrees part rotation). Altogether the head weighs 59 grams – lighter than an E3D v6.
In order to bring this project to its current state, [Daren] has had to perform some auxiliary hacks. The first was an aquarium to vacuum pump conversion – by switching around the valves and performing some other minor mods, [Daren] was able to produce a vacuum of 231mbar. The second was hacking a two-way solenoid valve from a coffee machine into a three-way unit. As [Daren] says, three-way valves are not expensive, but “a part in hand is worth two on Alibaba.”
[Angus Deveson] published a video on “solids of constant width” nearly a year ago. Following the release of the video, he had a deluge of requests asking if he could make a bearing from them. Since then, he’s tried a number of different approaches – none of which have worked. Until now…
What is a solid of constant width? A shape whose diameter is the same in all orientations, despite the fact that they aren’t circular. In particular, the Reuleaux Triangle is of interest; if you’ve heard of square drill bits, a Reuleaux Triangle is probably at play. Constructed from three circles, they make a neat geometrical study. When placed between two surfaces and rolled, the surfaces will stay parallel, despite the fact that the center of the triangle does not stay level.
In theory, this means they could be easily substituted for spheres in a classic roller bearing, but this turned out to be problematic – the first attempt determined how hard it was to get the shapes to roll instead of slide.
[Angus] finally arrived at a working bearing after a ton of suggestions from the community, and trying a number of attempts until he was able to achieve what he set out to do. The trick was to create a flexible insert (3D printed as well) for the center of the triangle edge, which grips the surfaces the triangle comes into contact with. A frame is also made to hold the bearings in place and allows their centers to move up and down as necessary.
If the thrill seeker within you still isn’t satisfied, maybe you should try the Reuleaux Coaster…
Continue reading “The Quest For The Reuleaux Triangle Bearing”
Moiré patterns are a thing of art, physics, and now tool design! [Julldozer] from Mojoptix creatively uses a moiré pattern to achieve a 0.05 mm precision goal for his custom designed 3D printed calipers. His calipers are designed to validate a 3D print against the original 3D model. When choosing which calipers are best for a job, he points out two critical features to measure them up against, accuracy and precision which he explains the definition of in his informative video. The accuracy and precision values he sets as constraints for his own design are 0.5 mm and 0.05 mm respectively.
By experimenting with different parameters of a moiré pattern: the scale of one pattern in relation to the other, the distance of the black lines on both images, and the thickness of black and white lines. [Julldozer] discovers that the latter is the best way to amplify and translate a small linear movement to a standout visual for measurement. Using a Python script which he makes available, he generates images for the moiré pattern by increasing line thickness ratios 50:50 to 95:5, black to white creating triangular moiré fringes that point to 1/100th of a millimeter. The centimeter and millimeter measurements are indicated by a traditional ruler layout.
Looking for more tool hacks and builds? Check out how to prolong the battery life of a pair of digital calipers and how to build a tiny hot wire foam cutter.
Continue reading “Precision DIY Calipers? That’s a Moiré!”