Retrotechtacular: Basic Telephony In The Field

March 24, 2015 by Kristina Panos 7 Comments

Here is a great introduction to a practical application of electromagnetic theory—the field telephone. It’s a training film from 1961 that covers the sound-powered, local battery, and common battery systems along with the six basic components they use: generators, ringers, transmitters, receivers, induction coils, and capacitors.

Clear illustrations and smart narration are the hallmarks of these Army training films, and this one begins with a great explanation of generator theory. The phone’s ringer uses electromagnetic attraction and repulsion to do the mechanical work of striking the bells. Similarly, the sound waves generated by a caller’s speech move an armature to create an alternating electrical current that is transmitted and converted back to sound waves on the receiving end.

In the local battery system, the battery pushes pulsating DC to carry the voice transmission. An induction coil increases the capabilities of this system, but capacitors are required to filter out the frequencies that would overload the receiver, passing only the higher speech frequencies.

In order for several stations to communicate, the use of a switchboard is required to patch the calls through. There are many advantages of a common battery system with regard to call switching: no local battery is necessary, nor is a generator needed at each station. Calls are easier to place, and communication is much faster.

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MRRF: Flexible 3D Printing

March 24, 2015 by Kristina Panos 13 Comments

The concession stand at the Midwest Rep Rap Festival did not disappoint when it came to the expected fare: hot dogs, walking tacos, and bananas for scale. But the yummiest things there could not be bought—the Nutella prints coming off the Ultimaker² at the structur3D booth.

3D printed gasket — Flexible gasket printed in silicone atop a rigid 3D printed engine block.

Hey, what? Yes, an Ultimaker² that can print in Nutella, icing sugar, silicone, latex, wood filler, conductive ink, polyurethane, peanut butter, and a growing list to which you should contribute. This is possible because of their Discov3ry Universal Paste Extruder add-on, which is compatible with most filament printers, especially those that use a RAMPs or Arduino control board.

A large syringe containing the substance of your choice is loaded business end up in the Discov3ry. It gets pushed through tubing that runs to the print head and out through one of many commonly available polypropylene or stainless steel tips. The structur3D team has found that printing on waxed paper works best for the materials they’ve proven out. Each syringe holds 60cc of stuff, and the Discov3ry comes with three of them. They are currently available for pre-order, with a shipping forecast of early summer.

Time For The Prize: Environment-Related Ideas

March 24, 2015 by Mike Szczys 38 Comments

You should already know about the 2015 Hackaday Prize, but have you submitted your entry yet? All it takes to get started is talking about one idea you have to address a problem faced by a large number of people. To help get the ball rolling we’re giving away some prizes to three entries that discuss possible solutions to Environment-Related problems.

For your chance at this week’s goodies all you need to do is document your idea on Hackaday.io and tag it “2015HackadayPrize”.

This Week’s Prizes:

On Monday, March 30th we’ll take a look at all the entries tagged 2015HackadayPrize and choose three that best fit the topic of Environment-Related. The best will receive the SmartMatrix 32×32 RGB LED matrix along with a Teensy 3.1 to drive it. The next pick will receive a Bus Pirate and probe cable. The final prize will be a Hackaday Robot Head Tee.

An Idea is All You Need for Entry

We’re not messing with you; all you need to win these early prizes is an idea. One of the most powerful pieces of the Hackaday Prize is the pollination of thought. Your idea might be the tipping point for someone else’s breakthrough or vice-versa. Start a project on Hackaday.io and add the tag “2015HackadayPrize”.

Pictured to the right is a whiteboard sketch by [MechaTweak] which illustrates one very simple shower water-saving idea (we think this was prompted by our column on the topic last week). The idea here is that instead of running water down the shower drain as you wait for it to heat up, the water cold be sequestered in a holding tank and used for flushing the toilet the rest of the day. This will certainly be in the running as it addresses the issue of water conservation. Going along with our Environment-related topic you might also tackle alternative energy production, helping detect or curb pollution, making recycling easier, reducing waste, etc.

As we move along we’ll be awarding bigger and better prizes. Submitting an idea now will give you an early start on your planning. You’ll still be eligible for future prizes, and you may submit as many entries as you like.

The 2015 Hackaday Prize is sponsored by:

Another Radio Module For IoT Fun – EMW3162

March 24, 2015 by Anool Mahidharia 24 Comments

The availability of cheap radio modules is making them ubiquitous in an increasing number of projects that we have been seeing recently. The usual go-to solution is using any one of the several modules based on the ESP8266 device. [Willem] wrote in to share with us his experiences with another radio module – the EMW3162 from MXChip, which at $10 isn’t as cheap as the ESP8266 modules, but is a more capable, power packed, device.

The EMW3162 (PDF datasheet) is a low-power embedded WiFi module with integrated wireless LAN, and a STM32F205 Cortex-M3 microcontroller that runs a “self-hosted” WiFi networking library and software application stack. The microcontroller has 1M flash, 128k RAM and runs at 120MHz. And since MXChip is a Broadcom partner, they are allowed to use the WICED_SDK.

The on-board ARM M3 means all kinds of useful interfaces are available: UART, SPI, I2C, ADC, DAC, PWM, TIMERS, GPIO, and a JTAG flash interface. The good news could be on the power consumption figures – the module is touted to be low-power, and the data sheet shows 7mA when connected to an access point but with no data transfer. When transmitting at 20kbps, the current draw is about 24mA, which goes up to 320mA at 11Mbps.

[Willem] has his EMW3162_WICED repository up on Github, but also take a look at the MXChips MICO (Mico-controller based Internet Connectivity Operation System) repository. At the moment, he has it working using Linux, with a gnu gcc compiler and a JLINK JTAG programmer. He also has the WICED SDK working and has a WiFi AP with an on-board 120MHz arm chip. It would be interesting to hear about other users’ experiences with this radio module. Do let us know in the comments below!

3D Printed Motorcycle Weighs Only 18kg

March 24, 2015 by James Hobson 39 Comments

After discovering 3D printing a few years ago, [Jonathan Brand] was hooked. He loved the ability to design things on a computer, and then have them realized as a real 3D object he can touch — sometimes within hours of doing the CAD work. He’s always wanted a motorcycle, but it was never the right time so at long last he decided to print one.

First off — no, it doesn’t actually work — it’s a 1:1 scale model of a 1972 Honda CB500. But it is an amazing testament to 3D printing and prototyping. He’s been working on it for almost as long as he’s had a 3D printer, and while he didn’t quote exactly how long it took to print everything, we’re guessing its in the thousands of hours.

In fact, he printed tons of components, labeled them, and organized them for up to a year before even being able to assemble them together. Talk about project dedication.

He’s even designed loose fits for moving parts — the wheels spin! To give it the cool transparent look, each part is actually almost completely hollow — with thin wall thickness of only about a millimeter. Because of this, the whole bike only weighs 18kg.

For a slightly more functional large-scale 3D print — how about printing your own colorful kayak?

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Control Stuff With Your Muscles

March 23, 2015 by Will Sweatman 17 Comments

[David Nghiem] has been working with circuitry designed to read signals from muscles for many years. After some bad luck with a start-up company, he didn’t give up and kept researching his idea. He has decided to share his innovations with the hacker community in the form of a wearable suit that reads muscle signals.

It turns out that when you flex a muscle, it gives off a signal called a Surface ElectroMyographic signal, or SEMG for short. [David] is using an Arduino, digital potentiometer and a bunch of op amps to read the SEMG signals. LEDs are used to display the signal levels.

The history behind [David’s] project dates back to the late twentieth century, which he eloquently points out – “Holy crap that was a long time ago”. He worked with the MIT Aero Astro Lab and the Boston University Neuromuscular Research Center where he worked on a robotic arm for astronauts. The idea being to apply an opposing force to the arm to help prevent muscle deterioration.

Be sure to check out [David’s] extensive and well documented work, along with the several videos showing his projects at various stages of completion. If this gives you the electromyography bug, check out this guide on detecting the signals and an application of the concept for robotic prosthesis.

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Get Blown Away By The Boominator

March 23, 2015 by Will Sweatman 22 Comments

You have a greater chance of squeezing 5 amps through a 2N2222 than you do remembering the 1980s and not thinking about the legendary ‘boom box’. They could be seen perched on the shoulders of rockers and rappers alike – many sporting the Members Only or red leather jackets. The boom boxes visual characteristics can best be described as a rectangular box with two very large speakers on each end. It is no accident that The Boominator shares these features.

[Jesse van der Zouw] did a good job of showing how he created The Boominator. It has not two, but four 10 inch woofers that delivers 360 degrees of awesomeness at 115dB. The on board battery can sustain it for up to twenty hours, and the project is topped off with some blue LED rings the encircle each speaker.

We’ve seen boom boxes here before, but this is the first with some nice LED accents. Be sure to check out this build and let us know what you might have done differently.

[via Hackaday.io]