Handheld LoRa Joystick For Long-Range Bots

September 11, 2019 by 11 Comments

Wanting a simple tool to aid in the development of LoRa controlled robotic projects, [Jay Doscher] put together this very slick one-handed controller based on the 900 MHz Adafruit Feather M0. With a single trigger and a miniature analog joystick it’s a fairly simple input device, but should be just enough to test basic functionality of whatever moving gadget you might find yourself working on.

Wiring for this project is about as simple as you’d expect, with the trigger and joystick hanging off the Feather’s digital ports. The CircuitPython code is also very straightforward, though [Jay] says in the future he might expand on this a bit to support LoRaWAN. The controller was designed as a barebones diagnostic tool, but the hardware and software in its current form offers an excellent opportunity to layer additional functionality on a known good base.

Everything is held inside a very well designed 3D printed enclosure which [Jay] ran off on his ELEGOO Mars, one of the new breed of low-cost resin 3D printers. The machine might be pretty cheap, but the results speak for themselves. While resin printing certainly has its downsides, it’s hard not to be impressed by the finish quality of this enclosure.

While LoRa is generally used for transmitting small bits of information over long distances, such as from remote sensors, this isn’t the first time we’ve seen it used for direct control of a moving object. If you’re not up to speed on LoRa, check out this excellent talk from [Reinier van der Lee] that goes over the basics of the technology and how he used it to build a community sensor network.

Smart Buoy Rides The Citizen Science Wave

September 11, 2019 by 9 Comments

Those beautiful and dangerous ocean waves that beckon us to the coast are more than just a pretty sight. They can tell us a lot about weather patterns and what the sea itself is doing. As vital as this information is, the existing methods of doing wave research are pretty expensive. The team at [t3chflicks] wanted to show it can be done fairly cheaply, to encourage more citizen scientists to contribute. More data means a better understanding, and open research benefits even those who don’t actively participate.

They have developed a smart buoy that collects wave data and transmits it back to a base station for real-time display. The buoy runs on an 18650 that gets recharged by four 5V solar panels situated around the top half of the 3D-printed hull. An Arduino inside the buoy controls the sensors, most of which are baked into the GY-86 10-DOF module. The antenna on top sends the data back to a Raspi Zero base station, which charts wave height, wave period, wave power, water and air temperature, and barometric pressure in real-time on a spiffy Vue JS dashboard.

The team had their ups and downs during this project. They wanted to measure wave direction, but it proved a bit too complicated. And memory issues prevented them from backing up the data to an on-buoy SD card. You can catch the more in-depth hardware and software videos on their YouTube channel. We’ve got the smart buoy summary video tied up and floating just after the break.

Want to help buoy wave research, but don’t have a 3D printer? Sealed PVC makes a fine flotation device, as we saw in this water quality-sensing buoy.

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Books You Should Read: Exact Constraint: Machine Design Using Kinematic Principles

September 11, 2019 by 53 Comments

Surely, if you’re reading this website you’ve teased the thought of building your own 3D printer. I certainly did. But from my years of repeated rebuilds of my homebrew laser cutter, I learned one thing: machine design is hard, and parts cost money. Rather than jump the gun and start iterating on a few machine builds like I’ve done before, I thought I’d try to tease out the founding principles of what makes a rock-solid machine. Along the way, I discovered this book: Exact Constraint: Machine Design Using Kinematic Principles by Douglass L. Blanding.

This book is a casual but thorough introduction to the design of machines using the method of exact constraint. This methodology invites us to carefully assess how parts connect and move relative to each other. Rather than exclusively relying on precision parts, like linear guides or bearings, to limit a machine’s degrees of freedom, this book shows us a means of restricting degrees of freedom by looking at the basic kinematic connections between parts. By doing so, we can save ourselves cost by using precision rails and bearings only in the places where absolutely necessary.

While this promise might seem abstract, consider the movements made by a 3D printer. Many styles of this machine rely on motor-driven movement along three orthogonal axes: X, Y, and Z. We usually restrict individual motor movement to a single axis by constraining it using a precision part, like a linear rod or rail. However, the details of how we physically constrain the motor’s movements using these parts is a non-trivial task. Overconstrain the axis, and it will either bind or wiggle. Underconstrain it, and it may translate or twist in unwanted directions. Properly constraining a machine’s degrees of freedom is a fundamental aspect of building a solid machine. This is the core subject of the book: how to join these precision parts together in a way that leads to precision movement only in the directions that we want them.

Part of what makes this book so fantastic is that it makes no heavy expectations about prior knowledge to pick up the basics, although be prepared to draw some diagrams. Concepts are unfolded in a generous step-by-step fashion with well-diagrammed examples. As you progress, the training wheels come loose, and examples become less-heavily decorated with annotations. In this sense, the book is extremely coherent as subsequent chapters build off ideas from the previous. While this may sound daunting, don’t fret! The entire book is only about 140 pages in length.

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Using Machinery To Make Factory-Fresh Industrial Music

September 11, 2019 by 5 Comments

Many machines make music as a side effect, as anyone who owns a 3D printer can confirm. [工場音楽レーベルINDUSTRIAL JP] is working on a project to meld music and machinery in new ways. They are building a record label and a playlist based on the sights and sounds of small factories in Japan. Their videos combine the hypnotizing, rhythmic beauty of precision manufacturing process with music from local artists, and the result is like r/SoundsLikeMusic met up with How It’s Made and created a series of un-narrated industrial fever dreams.

While the focus is on high-tech factories, the content of these moodily-lit videos is pretty diverse. Never before have we been so mesmerized by the folds of an air filter or the pressing of vinyl records. Our favorite might be GOKO BANE, which takes a bumpin’ look around the Goko Spring factory. It makes us want to throw on some rags and dance like they do down in Zion.

Once in a while they will play around with the video speed of the factory process for effect, and it works nicely. If there’s any downside, it’s that no one process is shown from start to finish. But that’s not the point, anyway.

Don’t have access to a factory? Us either. But if you can get stepper motors, it’s pretty easy to make music by driving them forward, or even backward.

Thanks for the tip, [KILLERGEEK].

Lambdas For C — Sort Of

September 11, 2019 by 49 Comments

A lot of programming languages these days feature lambda functions, or what I would be just as happy to call anonymous functions. Some people make a big deal out of these but the core idea is very simple. Sometimes you need a little snippet of code that you only need in one place — most commonly, as a callback function to pass another function — so why bother giving it a name? Depending on the language, there can be more to it that, especially if you get into closures and currying.

For example, in Python, the map function takes a function as an argument. Suppose you have a list and you want to capitalize each word in the list. A Python string has a capitalize method and you could write a loop to apply it to each element in the list. However, map and a lambda can do it more concisely:

map(lambda x: x.capitalize(), ['madam','im','adam'])

The anonymous function here takes an argument x and calls the capitalize method on it. The map call ensures that the anonymous function is called once for each item.

Modern C++ has lambda expressions. However, in C you have to define a function by name and pass a pointer — not a huge problem, but it can get messy if you have a lot of callback functions that you use only one time. It’s just hard to think up that many disposable function names. However, if you use gcc, there are some nonstandard C features you can use to get most of what you want out of lambda expressions.

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Pan And Tilt To A New 3D Printed Business Model

September 11, 2019 by 11 Comments

When shooting video, an easy way to get buttery smooth panning and tracking is to use a mechanical device like a rail to literally slide the camera side to side. These range from what is essentially a skateboard to incredible programmable multi-axis industrial robots, a wide variety of which have been visible in the backgrounds of Youtuber’s sets for years. But even the “low end” devices can run hundreds of dollars (all that anodized aluminum doesn’t come cheap!). Edelkrone has been building lust worthy professional (read, pricey) motion setups for a decade. But in the last year they’ve started something pretty unusual; lowering prices with their Ortak series of 3D printed equipment. But this time, you do the printing.

In the FlexTILT Head 3D, everything in red is printed at home

Since the RepRap we’ve been excited about the future of democratized at home manufacturing, but to a large extent that dream hasn’t materialized. Printers are much more useful now than in the early days but you can’t buy a new mug from Starbucks and print it at home. But maybe that’s changing with Edelkrone’s offering.

When you buy an Ortak product you get one thing: all the fasteners and hardware. So the final product is more durable and appears more finished than what would pop out of your Prusa unaided. What about the rest of the device? That’s free. Seriously. Edelkrone freely provides STLs (including print setting recommendations) with detailed step-by-step assembly instructions and videos (sample after the break). Nice hack to avoid piracy, isn’t it?

Why choose the do-it-at-home style product? A significant price reduction of course! The Ortak line currently includes two products, the FlexTILT head you see above, and a skateboard-style slide called the SKATER 3D. Both of these were sold fully finished before making it to the DIY scene. The FlexTILT Head 2 comes in at $149 when you buy it whole. And when the PocketSKATER 2 was for sale, it included a FlexTILT Head and came to $249. Now? Each hardware kit is just $29.

So is this it? Have we hit the artisanal DIY micro-manufactured utopian dream? Not yet, but maybe we’re a little closer. Edelkrone is a real company which is really selling these as products, right there on their website along with everything else. They refer to it as “co-manufacturing” which we think is a clever name, and talk about expanding the program to include electronics. We can’t wait to see how the experiment goes!

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Does Your Home Assistant Know When You Are Sleeping?

September 11, 2019 by 19 Comments

It always gives us a sense of wonder when we realize that what would be a simple task for a human child is a big deal for a computer. For example, if you asked someone if you or someone else was in bed, that’s a pretty simple thing to check. For you, that is. For a computer, it requires some sort of sensor. [Lewis] used load cells to tell if someone is in a particular bed or not. He uses Home Assistant and has a great post about how he created and interfaced the sensors. Of course, the sensors really only tell you if something heavy is in the bed. It doesn’t know who it is or even that it isn’t an overstuffed suitcase.

Load cells aren’t exactly high tech. There are several different types that use hydraulic pressure or pneumatics to measure force. However, the most common that we encounter use strain gauges. A strain gauge is a resistor that changes value when it deformed and a load cell usually has several strain gauges wired in a bridge configuration so that small forces create larger output changes.

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