Hackaday Prize Entry: Harmonicas, Candy, And Van Halen

Watch enough How It’s Made, and you’ll soon become very enthusiastic about computer vision and compressed air. In factories all around the world, production lines automatically sort the wheat from the chaff by running a product underneath a camera and blowing defective product off the line.

For his Hackaday Prize entry, [Fabien] is attempting this same task. He’s building a machine that will rapidly sort candy with computer vision and precisely controlled jets of air. He’s also planning for the Van Halen reunion and building a CNC harmonica.

Right now, the design has a hopper full of M&Ms dropping through a channel where a camera looks at each individual piece of candy. A Raspberry Pi, camera, and OpenMV detect all the red, yellow, brown, and blue M&Ms, and send that information to a computer controlling a suite of pneumatic valves. When these valves open, candy of different colors is shuffled off into it’s own bin. It’s the perfect device for someone responsible for reading Van Halen’s rider.

In an interesting little side project, [Fabien] needed a way to test the pneumatic valves before building the color sensor and candy chute. He had a harmonica lying around, and built something we’re surprised we’ve never seen before. It’s a CNC harmonica, capable of belting out a few tunes. You can check out that testing video after the break.

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DIY USB Type C

For many years, the humble serial port was one of the best ways to communicate with an embedded system. Then USB ports became more popular and serial ports started to vanish. These days, even if you’re using a serial protocol to communicate with the microcontroller, it’s often over USB. And USB provides a convenient source of 5 V too. In short, we’ve made our peace with USB.

And then they go and change it. USB type C is a small connector that is reversible and has more options for power and connectivity. However, it is yet another new interface to figure out. [Scorpia] recently posted an article about USB type C that you may find useful.

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Hack a Bike Electroetching

[Melka] wanted a track bike, but never quite got around to buying a nice one. Then he found an inexpensive abandoned project bike for 10 Euro. He had to do a lot of work to make it serviceable and he detailed it all in a forum post. What caught our eye, though, was his technique for electroetching.

The process is simple, but [Melka] says the procedure caused hydrochloric acid fumes as a byproduct. Your lungs don’t like HCl fumes. Apart from the danger, you probably have everything you need. He used electrical tape to create a stencil on the metal (although he mentioned that Kapton tape might come off better afterward) and a saturated solution of common table salt as the electrolyte.

Power comes from a bench power supply set to about 24V. The positive lead was connected to the metal and the ground to the sponge. From the photos, it looks like the particular piece and solution caused about 600mA to flow. After 10 minutes, the metal etched out to about 0.2 mm. After the etching, [Melka] brazed some brass into the etched area to make an interesting looking logo.

If you have a laser cutter, you can skip the chemicals. We’ve even seen laser etching combine with a 3D printer to produce PCBs. [Melka’s] method is a little messier and probably would not do fine lines readily, but if you need to etch steel and you don’t mind the fumes, it should be simple to try.

Smartphone-based Robotic Rover Project goes Open Source

[Aldric Négrier] wrote in to let us know that his DriveMyPhone project has been open sourced. The project is a part telepresence, part remote-controlled vehicle, part robotic rover concept on which he says “I spent more time […] than I should have.” He has shared not just the CAD files, but every detail including tips on assembly. He admits that maybe a robotic chassis for a smartphone might not seem like a particularly new idea today, but it was “an idea with more potential” back in 2010 when he first started.

The chassis is made to cradle a smartphone. Fire up your favorite videoconferencing software and you have a way to see where you’re going as well as hear (and speak to) your surroundings. Bluetooth communications between the phone and the chassis provides wireless control. That being said, this unit is clearly designed to be able to deal with far more challenging terrain than the average office environment, and has been designed to not only be attractive, but to be as accessible and open to repurposing and modification as possible.

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Minimal MQTT: Networked Nodes

Last time on Minimal MQTT, we used a Raspberry Pi to set up an MQTT broker — the central hub of a home data network. Now it’s time to add some sensor and display nodes and get this thing running. So pull out your ESP-8266 module of choice, and let’s get going.

DSCF8443For hardware, we’re using a WeMos D1 Mini because they’re really cute, and absolutely dirt cheap, but basically any ESP module will do. For instance, you can do the same on the simplest ESP-01 module if you’ve got your own USB-serial adapter and are willing to jumper some pins to get it into bootloader mode. If you insist on a deluxe development board that bears the Jolly Wrencher, we know some people.

NodeMCU: Getting the Firmware

We’re using the NodeMCU firmware because it’s quick and easy to get running. But you’re not stuck with NodeMCU if you want to go it alone: MQTT has broad support. [TuanPM] ported over an MQTT library to the native ESP8266 SDK and of course there’s espduino, a port for an Arduino-plus-ESP combo. He also ported the MQTT module to NodeMCU that we’ll be using today. Thanks, [TuanPM]!

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3D Printing and Modelling on the Fly

3D printing is supposed to be about rapid prototyping. Design, print, use, re-design, print, test — iterate until happy. But when you’re laying down filament at 60 mm/s, it can seem anything but rapid.

[Huaishu Peng], [Rundong Wu], and their supervisors at Cornell have come up with a 3D printer that can print almost as fast as you can model, and is able to add and subtract from the model on the fly. The goal is to get an initial model out so quickly that designing and printing can be truly interactive. They look to have succeeded — check out the video below.

3ders.org has a brilliant writeup of the machine that you should also go read once the video’s magic has worn off. There’s a lot going on to make this all work. The printer adds two extra degrees of freedom and a cutter head so that it can make additions and subtractions from the side, and is not constrained to layer-by-layer construction. To get the ABS to cool fast enough to make solid strands, water jets mist it down to temperature just after it’s printed.

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Beyond WD-40: Lubes for the Home Shop

If your shop is anything like mine, you’ve got a large selection of colorful cans claiming to contain the best and absolutely only lubricant you’ll ever need. I’ve been sucked in by the marketing more times than I care to admit, hoping that the next product will really set itself apart from the others and magically unstick all the stuck stuff in my mechanical life. It never happens, though, and in the end I generally find myself reaching for the familiar blue and yellow can of WD-40 for just about every job.

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