A Miniature Radio Telescope In Every Backyard

You probably wouldn’t expect to see somebody making astronomical observations during a cloudy day in the center of a dense urban area, but that’s exactly what was happening at the recent 2019 Philadelphia Mini Maker Faire. Professor James Aguirre of the University of Pennsylvania was there demonstrating the particularly compact Mini Radio Telescope (MRT) project built around an old DirecTV satellite dish and a smattering of low-cost components, giving visitors a view of the sky in a way most had never seen before.

Thanks to the project’s extensive online documentation, anyone with a spare satellite dish and a couple hundred dollars in support hardware can build their very own personal radio telescope that’s capable of observing objects in the sky no matter what the time of day or weather conditions are. Even if you’re not interested in peering into deep space from the comfort of your own home, the MRT offers a framework for building an automatic pan-and-tilt directional antenna platform that could be used for picking up signals from orbiting satellites.

With the slow collapse of satellite television in the United States these dishes are often free for the taking, and a fairly common sight on the sidewalk come garbage day. Perhaps there’s even one (or three) sitting on your own roof as you read this, waiting for a new lease on life in the Netflix Era.

Whether it’s to satisfy your own curiosity or because you want to follow in Professor Aguirre’s footsteps and use it as a tool for STEM outreach, projects like MRT make it easier than ever to build a functional DIY radio telescope.

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The Arduino IDE Finally Grows Up

While the Arduino has a very vocal fan club, there are always a few people less than thrilled with the ubiquitous ecosystem. While fans may just dismiss it as sour grapes, there are a few legitimate complaints you can fairly level at the stock setup. To address at least some of those concerns, Arduino is rolling out the Arduino Pro IDE and while it doesn’t completely address every shortcoming, it is worth a look and may grow to quiet down some of the other criticisms, given time.

For the record, we think the most meaningful critiques fall into three categories: 1) the primitive development environment, 2) the convoluted build system, and 3) the lack of debugging. Of course, there are third party answers for all of these problems, but now the Pro IDE at least answers the first one. As far as we can tell, the IDE hides the build process just like the original IDE. Debugging, though, will have to wait for a later build.

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DIY MIDI Looper Controller Looks Fantastic!

Due to pedalboard size, complicated guitar pedals sometimes reduce the number of buttons to the bare minimum. Many of these pedals are capable of being controlled with an external MIDI controller, however, and necessity being the mother of invention and all, this is a great opportunity to build something and learn some new skills at the same time. In need of a MIDI controller, Reddit user [Earthwin] built an Arduino powered one to control his Boss DD500 Looper pedal and the result is great looking.

Five 16×2 LCD screens, one for each button, show the functionality that that button currently has. They are attached (through some neat wiring) to a custom-built PCB which holds the Arduino that controls everything. The screens are mounted to an acrylic backplate which holds the screens in place while the laser-cut acrylic covers are mounted to the same plate through the chassis. The chassis is a standard Hammond aluminum box that was sanded down, primed and then filler was used to make the corners nice and smooth. Flat-top LEDs and custom 3D printed washers finish off the project.

[Earthwin] admits that this build might be overkill for the looper that he’s using, but he had fun building the controller and learning to use an Arduino. He’s already well on his way to building another, using the lessons learned in this build. If you want to build your own MIDI controller, this article should help you out. And then you’re ready to build your controller into a guitar if you want to.

[Via Reddit]

2D-Scanner Records Surfboard Profiles For Posterity

[Ryan Schenk] had a problem: he built the perfect surfboard. Normally that wouldn’t present a problem, but in this case, it did because [Ryan] had no idea how he carved the gentle curves on the bottom of the board. So he built this homebrew 2D-scanner to make the job of replicating his hand-carved board a bit easier.

Dubbed the Scanbot 69420 – interpretation of the number is left as an exercise for the reader, my dude – the scanner is pretty simple. It’s just an old mouse carrying a digital dial indicator from Harbor Freight. The mouse was gutted, with even the original ball replaced by an RC plane wheel. The optical encoder and buttons were hooked to an Arduino, as was the serial output of the dial indicator. The Arduino consolidates the data from both sensors and sends a stream of X- and Z-axis coordinates up the USB cable as the rig slides across the board on a straightedge. On the PC side, a Node.js program turns the raw data into a vector drawing that represents the profile of the board at that point. Curves are captured at various points along the length of the board, resulting in a series of curves that can be used to replicate the board.

Yes, this could have been done with a straightedge, a ruler, and a pencil and paper – or perhaps with a hacked set of calipers – but that wouldn’t be nearly as much fun. And we can certainly see applications for this far beyond the surfboard shop.

Upgrading A MIDI Controller With An FPGA

While the “M” in MIDI stands for “musical”, it’s possible to use this standard for other things as well. [s-ol] has been working on a VJ setup (mixing video instead of music) using various potentiometer-based hardware and MIDI to interface everything together. After becoming frustrated with drift in the potentiometers, he set out to outfit the entire rig with custom-built encoders.

[s-ol] designed the rotary-encoder based boards around an FPGA. It monitors the encoder for changes, controls eight RGB LEDs per knob, and even does capacitive touch sensing on the aluminum knob itself. The FPGA communicates via SPI with an Arduino master controller which communicates to a PC using a serial interface. This is [s-ol]’s first time diving into an FPGA project and it looks like he hit it out of the park!.

Even if you’re not mixing video or music, these encoders might be useful to any project where a standard analog potentiometer isn’t accurate or precise enough, or if you just need something that can dial into a specific value quickly. Potentiometers fall short in many different ways, but if you don’t want to replace them you might modify potentiometers to suit your purposes.

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Arduino Wire Bender Probably Won’t Kill All Humans

Do you want to make your own springs? Yeah, that’s what we thought. Well, blow the dust off of that spare Arduino and keep reading. A few months ago, we let you know that renowned circuit sculptor [Jiří Praus] was working on a precision wire-bending machine to help him hone his craft. Now it’s real, it’s spectacular, and it’s completely open source.

Along with that ‘duino you’ll need a CNC shield and a couple of NEMA 17 steppers — one to feed the wire and one to help bend it. Before being bent or coiled into springs, the wire must be super straight, so the wire coming off the spool holder runs through two sets of rollers before being fed into the bender.

[Jiří]’s main goal for this build was precision, which we can totally get behind. If you’re going to build a machine to do something for you, ideally, it should also do a better job than you alone. It’s his secondary goal that makes this build so extraordinary. [Jiří] wanted it to be easy to build with commonly-available hardware and a 3D printer. Every part is designed to be printed without supports. Bounce past the break to watch the build video.

You can also make your own springs on a lathe, or print them with hacked g-code.

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Review: OSEPP STEM Kit 1, A Beginner’s All-in-One Board Found In The Discount Aisle

As the name implies, the OSEP STEM board is an embedded project board primarily aimed at education. You use jumper wires to connect components and a visual block coding language to make it go.

I have fond memories of kits from companies like Radio Shack that had dozens of parts on a board, with spring terminals to connect them with jumper wires. Advertised with clickbait titles like “200 in 1”, you’d get a book showing how to wire the parts to make a radio, or an alarm, or a light blinker, or whatever.

The STEM Kit 1 is sort of a modern arduino-powered version of these kits. The board hosts a stand-alone Arduino UNO clone (included with the kit) and also has a host of things you might want to hook to it. Things like the speakers and stepper motors have drivers on board so you can easily drive them from the arduino. You get a bunch of jumper wires to make the connections, too. Most things that need to be connected to something permanently (like ground) are prewired on the PCB. The other connections use a single pin. You can see this arrangement with the three rotary pots which have a single pin next to the label (“POT1”, etc.).

I’m a sucker for a sale, so when I saw a local store had OSEPP’s STEM board for about $30, I had to pick one up. The suggested price for these boards is $150, but most of the time I see them listed for about $100. At the deeply discounted price I couldn’t resist checking it out.

So does an embedded many-in-one project kit like this one live up to that legacy? I spent some time with the board. Bottom line, if you can find a deal on the price I think it’s worth it. At full price, perhaps not. Join me after the break as I walk through what the OSEPP has to offer.

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