Author: Richard Baguley

244 Articles

Spanning The Tree : Dr Radia Perlman & Untangling Networks

May 29, 2018 by 33 Comments

As computer networks get bigger, it becomes increasingly hard to keep track of the flow of data over this network. How do you route data, making sure that the data is spread to all parts of the network? You use an algorithm called the spanning tree protocol — just one of the contributions to computer science of a remarkable engineer, Dr. Radia Perlman. But before she created this fundamental Internet protocol, she also worked on LOGO, the first programming language for children, creating a dialect for toddlers.

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Lucky Cat POV Display Ditches The Waving And Windmills Out Of Control

May 15, 2018 by 10 Comments

If you’ve been in a Japanese restaurant, you’ve probably seen a maneki-neko, the lucky cat charm, where a cat welcomes you with a beckoning arm. It’s considered to bring good luck, but we’re not sure if [Martin Fitzpatrick] is pushing his luck with this Lucky Cat POV display. He hacked one of the figurines so the arm forms a persistence of vision (POV) display, where blinking LEDs on the paw create a dot-matrix style display.

Inside the hapless neko is a Wemos D1, motor driver, and a few other components that turn the cat into a working display. The five LEDs he attached to the paw are wide enough to display 5×7 characters. The tricky part in the mechanical design is getting signals from a stationary base to a spinning arm(ature). In this case it was easily solved with a 6-wire slip ring from Adafruit. [Martin] revs the lucky cat up using a brushed DC motor and a couple of gears.

The ESP8266 is running MicroPython — the combination should make this a snap to hook into any web service API you want to display your own messages. Right now the arm doesn’t have positional awareness so the message isn’t locked in a single position like it would be if a hall effect sensor was used. But [Martin] says there’s plenty of room left inside the cat and a future upgrade could include stashing the batteries inside for a cordless, all-in-one build. If he takes that on it’s a perfect time to add some type of shaft encoding as well.

Check the Lucky Cat showing off in the clip after the break.

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Sophie Wilson: ARM And How Making Things Simpler Made Them Faster & More Efficient

May 8, 2018 by 84 Comments

Sophie Wilson is one of the leading lights of modern CPU design. In the 1980s, she and colleague Steve Furber designed the ARM architecture, a new approach to CPU design that made mobile computing possible. They did this by realizing that you could do more, and quicker, with less. If you’ve use a Raspberry Pi, or any of the myriad of embedded devices that run on ARM chips, you’ve enjoyed the fruits of their labor.

It all began for Sophie Wilson with an electric lighter and a slot machine (or fruit machine, as they are called in the UK) in 1978. An aspiring thief had figured out that if you sparked an electric lighter next to the machine, the resulting wideband electromagnetic pulse could trigger the payout circuit. Electronics designer Hermann Hauser had been tasked with fixing the problem, and he turned to Wilson, a student working at his company.

Wilson quickly figured that if you added a small wideband radio receiver to detect the pulse, you could suppress the false payout, foiling the thief. Impressed with this innovation, Hauser challenged Wilson to build a computer over the summer holidays, based in part on a design for an automated cow feeder that Wilson had created at university. Wilson created this prototype computer that looked more like a hand-wired calculator than a modern computer, but the design became the basis for the Acorn System 1, the first computer that Hauser’s new company Acorn Computers launched in 1979. Continue reading “Sophie Wilson: ARM And How Making Things Simpler Made Them Faster & More Efficient” →

Alexa, Attack Intruders

May 8, 2018 by 3 Comments

If our doom at the hands of our robot overlords is coming, I for one welcome the chance to get a preview of how they might go about it. That’s the idea behind Project Icarus, an Alexa-enabled face-tracking Nerf turret. Designed by [Nick Engmann],  this impressive (or terrifying) project is built around a Nerf Vulcan, a foam dart firing machine gun mounted on a panning turret that is hidden behind a drop-down cabinet door. This is connected to a Pi Zero equipped with a Pi camera. The Zero is running OpenCV and Google Firebase, which connects it with Amazon’s Alexa service.

It works like this: you say “Alexa, open Project Icarus”. Through the Alexa skill that [Nick] created, this connects to the Pi and starts the system. If you then say “Alexa, activate alpha”, it triggers a relay to open the cabinet and the Nerf gun starts panning around, while the camera mounted on the top of it searches for faces. The command “Alexa, activate beta” triggers the Nerf to open fire.

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LoRa System Commands Drones From A Distance

May 5, 2018 by 11 Comments

LoRa has been making quite a stir in hacker circles over the past couple of years, as it offers a fascinating combination of long range, low power, and low cost. It does this by using spread spectrum techniques on unlicensed frequency bands, meaning it can send data a surprising distance and that you don’t need a radio license to use it. It is mainly used for Internet of Things things, but [Paweł Spychalski] has other ideas: he’s building a system to use it to control a quadcopter drone over distances of 5 kilometers or more. That’s an ambitious aim, considering that the parts he is using cost only a few bucks.

He’s using an off-brand Adafruit Feather LoRa board and a couple of home-made antennas with his own software that takes the data from the Taranis control port of the RC controller, encodes it and chirps it out over the LoRa radio. At the other end, a similar radio receives and decodes the data, feeding it out to the drone.

This is definitely still a work in progress, but he has got it working, flying his drone over the link, keeping control of it out to several hundred meters. At the moment, he can’t go much further as it seems that his LoRa radio is being overwhelmed by the video link on the drone, but he is working on changing the frequency spread & hopping and using a better antenna to provide longer range. We’ve seen some interesting stuff from [Pawel] before, like his DIY telemetry system, so this project is worth keeping an eye on if you are a drone fan.

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Simple Home-built Projection Clock Projects Time

May 5, 2018 by 13 Comments

There are plenty of cheap projection clocks available, but as [Thomas Pototschnig] points out in this project, where’s the fun in just buying something? He set out to build a cheap projection clock using a small LCD screen, a cheap LED backlight, and a cheap lens. Cheap is the order of the day here, and [Thomas] succeeded admirably, creating a design that can be made with a couple of cheap PCBs, a 3D printer and the other parts mentioned above. He does a nice job of laying out his thinking in this design, showing how he calculated the projection path and made other decisions. His project has room to grow as well: it runs from an Arduino compatible STM32 that could handle many things other than showing the time if you were inclined to expand the project further.

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Commodore 64 To Raspberry Pi Conversion Is Respectful & Complete

May 4, 2018 by 27 Comments

We’re big fans of taking old computers and giving them a new lease on life, but only when it is done respectfully. That means no cutting, no hot glue, and no gouging out bits to make the new computer fit. It’s best if it can be done in a way that the original parts can be restored if required.

This Commodore 64 to Raspberry Pi conversion from [Mattsoft] definitely fits our criteria here, as it uses the old keyboard, joystick connectors and output portholes for the required authentic look. It does this through the clever use of a couple of 3D-printed parts that hold the Raspberry Pi and outputs in place, mounting them to use the original screw holes in the case.

Combine the Pi with a Keyrah V2 to connect the C64 keyboard and a PowerBlock to juice up all of the parts, and you’ve got a fully updated C64 that can use the keyboard, joysticks or other peripherals, but which also comes with a HDMI port, USB and other more modern goodies.

[Mattsoft] suggests using Combian 64, a C64 emulator for the Pi for the authentic look and feel. Personally, I might use it as a thin client to the big-ass PC with 16 CPU cores and 32GB of memory that’s hidden in my basement, but that’s just because I enjoy confusing people.