Very Detailed BB-8 Robot Build

January 9, 2016 by 19 Comments

[James Bruton] has just finished and posted the designs for his very impressive BB-8 robot build. We covered the start of his adventures some time ago when we were theorizing about the secret in the new droid, but it was for a completely different robot design. [James] was pursuing a design that used a little robot sitting on top of a big ball.

This new version has a robot sitting inside a ball with the head being magnetically coupled to the body. Among many things with this build, we thought it was cool how the robot has one drive motor and turns by spinning up and reversing a big flywheel in the base of the robot. That was certainly not one of the top theories proposed for the secret behind the robot. The robot is mostly made with a 3d printer, with the occasional cosmetic piece being vacuum formed. If you’d like to make one for yourself, [James] has also posted all of the design and cad for the robot on his GitHub. On Thursday he posted the final installment of his 10-part video series on the build. Check out part one after the break.

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FM 101 And Transmitter Build With Afroman

January 9, 2016 by 18 Comments

One of our favorite purveyors of electronics knowledge is at it again. This time, [Afroman] explains how frequency modulation works while building up a short-range FM transmitter on a board he has available at OSH Park.

The design is based on a MAX2606 voltage-controlled oscillator (VCO) chip that can do 70-150MHz. [Afroman] sets it up to oscillate at about 100MHz using a 390nH inductor. He also put a potentiometer voltage divider on the 2606’s tuning pin. Voltage changes issued through the pot alter the transmitting frequency in small increments, making it easy to dial in a suitable channel for your broadcast. Add an electret mic and about a meter’s worth of solid-core wire and you have yourself an FM transmitter that is good for around 20 meters.

There are plenty of ways to build a small FM transmitter that allow for some experimentation and don’t involve placing SMD components. We covered a build last summer that uses a couple of 3904s and rides a 9V connector salvaged from a dead battery. The downside is that transistor-based transmitters tend to be less frequency-stable than a VCO chip.

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Building Triodes With Blinker Fluid

January 9, 2016 by 67 Comments

The triode is one of the simplest kinds of vacuum tubes. Inside its evacuated glass envelope, the triode really is just a few bits of wire and metal. Triodes are able to amplify signals simply by heating a cathode, and modulating the flow of electrons to the anode with a control grid. Triodes, and their semiconductor cousin the transistor, are the basis of everything we do with electricity.

Because triodes are so fantastically simple, they’re the parts most commonly crafted by the homebrew tube artisans of today. You don’t need a glass blowing lathe to make the most basic vacuum tube, though: [Marcel] built one from the light bulb used in a car’s tail light.

The light bulb in your car’s tail light has two filaments inside: one for the normal tail light, and a second one that comes on when you brake. By burning out the dimmer filament, [Marcel] created the simplest vacuum tube device possible. In his first experiment, he turned this broken light bulb into a diode by using the disconnected filament as the anode, and the burning filament as the cathode. [Marcel] attached a 1M resistor and measured 30mV across it. It was a diode, with 30μA flowing.

The triode is just a diode with a grid, but [Marcel] couldn’t open up the light bulb to install a piece of metal. Instead, he wrapped the bulb in aluminum foil. After many attempts, [Marcel] eventually got some amplification out of his light bulb triode.

The performance is terrible – this light bulb triode actually has an “amplification” of -108dB, making it a complete waste of energy and time. It does demonstrate the concept though, even though the grid isn’t between the anode and cathode, and this light bulb is probably filled with argon. It does work in the most perverse sense of the word,  and makes for a very interesting build.

Video Gives You The Basics Of DIY Rotary Encoders

January 8, 2016 by 45 Comments

Is it really possible to build a rotary encoder out of a flattened tin can and a couple of photodetectors? Sure it’s possible, but what kind of resolution are you going to get from such a contraption? Is there any way that you’d be able to put them to work in a DIY project like a CNC router? If you pay attention to the basics then the answer is yes, and [HomoFaciens] wants to prove that to you with this detailed video on homebrew encoder design.

Faithful Hackaday readers will no doubt recognize [HomoFaciens] from a number of prior appearances on these pages, including this recent hardware store CNC router build. When we first ran across his builds, we admit a snicker or two was had at the homemade encoders, but if you watch the results he manages to get out of his builds, you quickly realize how much you can accomplish with very little. The video is a primer on encoder design, walking you through the basics of sensing rotation with phototransistors, and how a pair of detectors is needed to determine the direction of rotation. He also discusses the relative merits of the number of teeth in the chopper; turns out more isn’t necessarily better. And in the end he manages to turn a car wiper motor into a high-torque servo, which could be a handy trick to have filed away.

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Internet Of Things In Five Minutes

January 8, 2016 by 22 Comments

If you’re looking for the quickest way to go from zero to voice-controlled home automation system, you should spend five minutes checking out [Hari Wiguna]’s project on Hackaday.io where he connects up IoT gadgets and services into a functioning lightswitch. (Video below the break.)

6166971452133983621[Hari] demonstrates how to set up a complex chain: Amazon Echo to IFTTT to Adafruit.io as a data broker, which is then polled by an ESP8266 unit in his home that controls his X10 setup. (Pshwew.) But each step along the way is designed to be nearly plug-and-play, so it’s really a lot like clicking Lego blocks together. [Hari]’s video is a nice overview.

There’s only one catch if you’re going to replicate this yourself: the X10 system that’s used for the last mile. Unless you have one of these setups already, you’re on your own for controlling the outlets that turn the lights on and off. For price and hackability, we suggest the common 433MHz wireless outlet switches and pairing them with cheap 433MHz transmitters, available at eBay for around $1. We’ve seen a lot of hacks of these systems — they’re quite common both in the US and Europe.

We’ve also covered [Hari]’s projects before: both his self-learning TV remote and a sweet Halloween hack. His video production skills are excellent. We’re in awe of how much info he crams into his YouTube videos.

Zedboard Multiport Ethernet

January 8, 2016 by 9 Comments

The Zedboard uses Xilinx’s Zynq, which is a combination ARM CPU and FPGA. [Jeff Johnson] recently posted an excellent two-part tutorial covering using a Zedboard with multiple Ethernet ports. The lwIP (light-weight Internet Protocol) stack takes care of the software end.

Vivado is Xilinx’s software for configuring the Zynq (among other chips), and the tutorial shows you how to use it. The Ethernet PHY is an FPGA Mezzanine Card (FMC) with four ports that is commercially available. The project uses VHDL, but there is no VHDL coding involved, just the use of canned components.

The real issue when using an FPGA and a CPU is the interface between the processor and the FPGA circuitry. In this case, the ARM standard AXI bus does this task, and the Ethernet component properly interfaces to that bus. The IP application in the second part of the post is an echo server.

We’ve seen the Zynq used in flying machines and also in a music synthesizer. Although this project doesn’t use any Verilog or VHDL that you create, it is still a great example of configuring using Vivado and using common components in a design.

Baby Saved By Doctors Using Google Cardboard After 3D Printer Fails

January 8, 2016 by 64 Comments

It’s a parent’s worst nightmare. Doctors tell you that your baby is sick and there’s nothing they can do. Luckily though, a combination of hacks led to a happy ending for [Teegan Lexcen] and her family.

When [Cassidy and Chad Lexcen]’s twin daughters were born in August, smaller twin [Teegan] was clearly in trouble. Diagnostics at the Minnesota hospital confirmed that she had been born with only one lung and half a heart. [Teegan]’s parents went home and prepared for the inevitable, but after two months, she was still alive. [Cassidy and Chad] started looking for second opinions, and after a few false starts, [Teegan]’s scans ended up at Miami’s Nicklaus Children’s Hospital, where the cardiac team looked them over. They ordered a 3D print of the scans to help visualize possible surgical fixes, but the 3D printer broke.

Not giving up, they threw [Teegan]’s scans into Sketchfab, slapped an iPhone into a Google Cardboard that one of the docs had been playing with in his office, and were able to see a surgical solution to [Teegan]’s problem. Not only was Cardboard able to make up for the wonky 3D printer, it was able to surpass it – the 3D print would only have been the of the heart, while the VR images showed the heart in the context of the rest of the thoracic cavity.[Dr. Redmond Burke] and his team were able to fix [Teegan]’s heart in early December, and she should be able to go home in a few weeks to join her sister [Riley] and make a complete recovery.

We love the effect that creative use of technology can have on our lives. We’ve already seen a husband using the same Sketchfab tool to find a neurologist that remove his wife’s brain tumor. Now this is a great example of doctors doing what it takes to better leverage the data at their disposal to make important decisions.