Finally, A Usable Rotary Phone From A Conference Badge

November 9, 2019 by Jenny List 2 Comments

A few weeks ago we featured a project from [Dan], a work-in-progress in which he was attaching an EMF 2018 electronic conference badge to a rotary phone. At the time we looked forward to his progress, expecting maybe to see it in our travels round the field at EMF 2021. We have to say we did him a disservice then, because he’s made excellent progress and has now turned it into a fully functional cellular rotary phone.

When we left him he’d interfaced the dial to the badge and not a lot else, but it was enough to spark our interest because we think there should be more re-use of old electronic conference badges. Since then he’s reverse engineered the original bell with the help of a motor driver and a cheap DC-to-DC converter, and the handset with the guts of a Bluetooth headset because in experimenting he managed to kill the badge’s audio circuitry.

The result can be seen in the video below the break, and we have to admit it looks pretty good. Depending where you are in the world you’ll either love or hate the ringing sound, but that is of little consequence to the utility of the device. If you have a drawer full of conference badges gathering dust, perhaps it’s time to give them a second look.

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Just How Simple Can A Transceiver Be?

November 9, 2019 by Jenny List 20 Comments

We’ve frequently talked about amateur radio on these pages, both in terms of the breadth of the hobby and the surprisingly low barrier to entry. It’s certainly the case that amateur radio does not have to mean endlessly calling CQ on SSB with an eye-wateringly expensive rig, and [Bill Meara N2CQR] is on hand with a description of a transceiver that’s so simple it only uses one transistor.

It’s a 40 meter (7 MHz) QRP or low power transceiver in which the transmitter is a simple crystal oscillator and the receiver is an equally simple regenerative design. What makes it so simple is the addition of a three-way switch to transfer the single transistor — a J310 FET — between the two halves of the circuit. It’s no slouch as QRP radios go, having clocked up real-world contacts.

This circuit shows us how a little can go a long way in the world of amateur radio, and we can’t help liking it for that. It’s worth saying though that it’s not without flaws, as a key click filter and another transistor would make for a much higher quality transmitted signal. But then it would no longer be a single-transistor rig, and thus would miss the point, wouldn’t it.

The Rotodyne Fails To Take Off

November 9, 2019 by Al Williams 45 Comments

Bacon and eggs, chocolate and peanut butter, salt and pepper; some things just go together. You’d think that a mashup of an airplane and a helicopter would be great, right? The Fairey Rotodyne was just such a thing from the late 1950s and while it looked to be the wave of the future, it never took off — at least, not in the business sense at least. [Mustard] has an excellent video about the machine including some flight footage and explains why it failed to take over the aviation market. You can watch the video below.

While it does look like a helicopter mated with an airplane, it’s actually a bit different. The rotor isn’t normally powered at all. However, it does turn in forward flight and generates about half the lift the plane needs. That explains the stubby wings. The topside rotor has small jets at the tips that can be used during vertical take off, landing, and hovering modes.

For its time, it was fast and efficient, especially compared to contemporary helicopters. This type of plane was known as an autogyro and actually appeared in the 1930s as a safety mechanism since an autogyro can land in an autorotation mode.

According to the video, the noisy tip jets and production delays killed the beast. There was only one prototype built, but there was something we found very attractive about it. There have been, of course, other autogyros. British, German, Japanese, and Russian military have used autogyros at one time or another. The United States Postal Service was known to employ at least one.

Even today, there are about a thousand autogyros used by different military and police organizations. They are cheaper than a helicopter to buy and fly. Sadly, though, it doesn’t look like autogyros will ever become a common sight. Like an airship, they seem like a callback to an earlier time when you have a chance to spot one.

We are always surprised we don’t see more model autogyros. We wonder how they’d be at cutting down trees.

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Use Your Earbud’s Media Controls On Your Laptop With This Useful Dongle

November 9, 2019 by Gerrit Coetzee 3 Comments

[David] sends in his very nicely designed “Thumpware Media Controller” that lets your mobile phone headphones control the media playback on your PC.

We realize that some PCs have support for the extra pins on cellphone earbuds, but at least some of us have experienced the frustration (however small) of habitually reaching up to touch the media controls on our earbuds only to hear the forlorn click of an inactive-button. This solves that, assuming you’re still holding on to those 3.5mm headphones, at least.

The media controls are intercepted by a PIC16 and a small board splits and interprets the signals into a male 3.5mm and a USB port. What really impressed us is the professional-looking design and enclosure. A lot of care was taken to plan out the wiring, assembly, and strain relief. Overall it’s a pleasure to look at.

All the files are available, so with a bit of soldering, hacking, and careful sanding someone could put together a professional looking dongle for their own set-up.

Weather Station Gets Much-Needed Upgrades

November 9, 2019 by Bryan Cockfield 8 Comments

Weather stations are a popular project, partly because it’s helpful (and interesting) to know about the weather at your exact location rather than a forecast that might be vaguely in your zip code. They’re also popular because they’re a good way to get experience with microcontrollers, sensors, I/O, and communications protocols. Your own build may also be easily upgradeable as the years go by, and [Tysonpower] shows us some of the upgrades he’s made to the popular Sparkfun weather station from a few years ago.

The Sparkfun station is a good basis for a build though, it just needs some updates. The first was that the sensor package isn’t readily available though, but some hunting on Aliexpress netted a similar set of sensors from China. A Wemos D1 Mini was used as a replacement controller, and with it all buttoned up and programmed it turns out to be slightly cheaper (and more up-to-date) than the original Sparkfun station.

All of the parts and code for this new station are available on [Tysonpower]’s Github page, and if you want to take a look at a similar station that we’ve featured here before, there’s one from three years ago that’s also solar-powered.

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Sensing, Connected, Utility Transport Taxi For Level Environments

November 9, 2019 by Anool Mahidharia 3 Comments

If that sounds like a mouthful, just call it SCUTTLE – the open-source mobile robot designed at Texas A&M University. SCUTTLE is a low cost (under $350) robot designed for teaching Aggies at the Multidisciplinary Engineering Technology (MXET) program, where it is used for in-lab lessons and semester projects for the MXET 300 – Mobile Robotics undergraduate course. Since it is designed for academic purposes, the robot is very well documented, making it easy to replicate when you follow the instructions. In fact, the team is looking for others to build SCUTTLE’s and give them feedback in order to improve its design.

Available on the SCUTTLE website are a large collection of videos to walk you through fabrication, electronics setup, robot assembly, programming, and robot operation. They are designed to help students build and operate the mobile robot within one semester. Most of the mechanical and electronics parts needed for the robot are off-the-shelf and easy to procure and the rest of the custom parts can be easily 3D printed. Its modular design allows you the freedom to try different options, features and upgrades. SCUTTLE is powerful enough to carry a payload up to 9 kg (20 pounds) allowing additional hardware to be added. To keep cost low and construction easy, the robot uses a simple, two wheel drive system, using a pair of geared motors. This forces the robot to literally scuttle in a “non-holonomic” fashion to move from origin to destination in a sequence of left / right turns and forward moves, so motion planning is interestingly tricky.

The SCUTTLE robot is programmed using Python3 running under Linux and has been tested working on either a BeagleBone Blue or a Raspberry Pi. The SCUTTLE software guide is a good place to get acquainted with the system architecture.

The standard configuration uses ultrasonic sensors for collision avoidance, a standard USB camera for vision, and encoders coupled to the wheel drive pulleys for determining position with respect to the starting origin. An optional USB LiDAR can be added for area mapping. The additional payload capability allows adding on extra sensors, actuators or battery packs.

To complement information on the website, additional resources are posted on GitHub, GrabCAD and YouTube. Building a SCUTTLE robot ought to be a great group project at maker spaces wanting to get hackers started with Robotics. We have covered many Educational Robot projects in the past, but the SCUTTLE really shines with its ability to carry a pretty decent payload at a low cost.

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Plan Ahead: Roaming Charges Are A Killer

November 9, 2019 by Al Williams 20 Comments

As the world gets more connected and computerized, it is easy to have an unintended consequence pop up and bite you. Especially because, so much of the time, today, things just work. The days of fretting over how to connect two computers, or how to store reasonable amounts of data are gone. Most of us never have to sift through assembly language programs finding three extra bytes to add a feature. Some Russian scientists recently found out about unintended consequences the hard way.

In the United States, the Eagle was long on the endangered species list, but apparently they have a similar problem in Russia. Scientists put a tracker on some migrating eagles in southern Russia and Kazakhstan. A few decades ago, this would have been a big technical challenge, but now you just use cellular technology and have the tracker text its location, right?

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