Roku TV Hacked To Run Philips Ambilight Setup

May 20, 2021 by Lewin Day 24 Comments

Roku TVs are interesting beasts, which use automatic content recognition on whatever you happen to be watching in order to market online streaming services direct to your loungeroom. [Ammar Askar] realised that this technology could instead be used to feed data to a computer to run a Philips Ambilight setup natively from whatever the TV displays.

The core of the hack came about because [Ammar’s] TV doesn’t work natively with Philips Ambilight technology. Most off-the-shelf solutions involve feeding sources, like Chromecasts or game consoles, to a HDMI splitter and then to a PC running the Ambilight software, but it gets messy real quick. Instead, [Ammar] realised that the Roku-enabled TV should be more than capable of working with the Ambilight system, given the capability of its inbuilt hardware.

The hack consists of a custom app running on the Roku hardware, which uses the in-built Roku libraries to capture frames of whatever is being displayed on the TV. It then breaks up the screen into sections and averages the color in each area. This data is then passed to a laptop, which displays the relevant colors on its own screen, where the standard Philips Hue Sync app handles the Ambilight duties.

It’s a great hack and [Ammar] doesn’t skimp on the granular fine details of what it took to get this custom code running on the Roku TV. We’d love to see more hacks of this calibre done on smart TVs; after all, there’s plenty of horsepower under the hood in many cases. Alternatively, you could always follow the CIA’s example and turn your Samsung TV into a covert listening device. Video after the break.

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Practical Sensors: The Hall Effect

May 20, 2021 by Al Williams 22 Comments

Measuring a magnetic field can be very easy with some pretty low tech, or it can be very high tech. It just depends on what kind of measurement you need and how much effort you want to expend. The very simplest magnetic sensors are reed switches. These are basically relays with no coil. Instead of a coil, an external magnet gets close enough to make or break the contacts in the reed. You see these a lot in, for example, door alarm sensors.

Then again, there’s no real finesse to a reed. It changes state when it sees enough of a magnetic field and that’s about all. You could use a compass with some sort of detection on the needle to get some more information about the field, but not much more. That was, however, how early magnetometers worked. Today, you have lots of options, including the nearly ubiquitous Hall effect sensor.

You might use a Hall effect to measure the magnetic button on a keyboard key coming down when you press it or the open and closed state of a valve. A lot of Hall effects see service as current monitors. Since a coil generates a magnetic field proportional to the current through it, a magnetic sensor can estimate the current in a coil of wire without any physical contact. Hall effects can also watch a magnet go by in a linear motion system or a rotating system to get an idea of position or speed. For example, check out this brushless motor controller that uses three sensors to understand the motor’s position.

History

Edwin Hall identified the effect in 1879. The basic idea is simple: an electrical conductor carrying current will exhibit changes due to an external magnetic field nearby. These changes show up as voltage you measure across the conductor. Normally, the voltage across a conductor will be nearly zero, but with a magnetic field, you’ll get a non-zero reading in proportion to the magnetic field strength in a particular plane, as we’ll see shortly.

Hall effect sensors are just one type of modern magnetometer. There are many different kinds including those that use inductive pickup coils that may or may not rotate or a fluxgate, which is a special type of coil. Some use a scale or a spring to measure force against another magnet — sometimes microscopically. You can even detect a magnetic field using optical properties like the Kerr effect or Faraday rotation.

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3D Printing Omni-Balls For Robot Locomotion

May 20, 2021 by Lewin Day 6 Comments

Wheels are all well and good for getting around, but they only tend to rotate about a single axis. Omni-wheels exist, but they’re still a little too pedestrian for [James Bruton]. His latest project involved 3D printing custom omni-balls which roll in all directions. (Video, embedded below.)

The omniball concept comes from earlier work by Osaka University, which also produced a treaded tank-like vehicle by the name OmniCrawler as well. The spherical design, fitted with an axle and casters as well, allows rotation in multiple directions, allowing for a platform fitted with such omni-balls to easily rotate and translate in all directions.

[James] set about creating his own version of the design, which relies on grippy TPU filament for grip pads to give the 3D printed hemispheres some much needed grip. There’s also bearings inside to allow for the relative rotation between the hemispheres and the internal castor, necessary to allow the wheels to move smoothly when sitting on either pole of the hemispheres. Skate bearings were then used to assemble three of the omni-balls onto a single platform, which demonstrated the ability of the balls to roll smoothly in all directions.

While it’s just a demonstration of the basic idea for now, we can imagine these balls being used to great effect for a robot platform that needs to navigate in tight spaces on smooth surfaces with ease. The mechanical complexity of the omni-balls probably negates their effective use in dirtier offroad contexts, however.

We’ve seen [James]’s work before too – such as his compliant leg design for walking robots, and his active gyroscope balancer last week. When does [James] sleep?

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Freenode Debacle Prompts Staff Exodus, New Network

May 20, 2021 by Tom Nardi 68 Comments

It’s no secret that Internet Relay Chat (IRC) has lost some of its appeal in recent years. These days there’s plenty of free chat platforms boasting slick web interfaces and smartphone push notifications, to say nothing of social networks like Facebook and Twitter. The ability to communicate with like minded individuals from all over the planet in real-time is now something we take for granted, so it’s little surprise that newer and flashier protocols and services have steadily eroded the IRC user base.

But there’s often a hidden cost to using these more modern communication protocols. A lack of operational transparency naturally leads to concerns over monitoring and censorship, which makes such services a poor match for the free and open source community. As such, many open projects have eschewed these newer and more popular services for IRC networks that were developed and maintained by the community itself. Among these, the best-known and most respected is Freenode. Originally started as a Linux support channel in 1995, Freenode grew to become the defacto communication and support tool for free and open source projects of all shapes and sizes, and by 2013 had officially become the largest and most active IRC network in the world.

Unfortunately, the incredible legacy of Freenode is now being jeopardized by what former staff members are describing as nothing short of a hostile takeover. Through a complex series of events which actually started several years ago, control of Freenode has been taken from the community and put into the hands of an enigmatic and wealthy entrepreneur who claims his ultimate goal is to revolutionize IRC and return it to the forefront of online communication. Here’s where it gets weird.

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Terminal Magic With Notcurses

May 20, 2021 by Jonathan Bennett 10 Comments

Writing a command line program that needs a little more pizzaz? Ncurses just not colorful or high res enough? Or maybe you want to bring the demo scene to the command line. Notcurses has your back. The demo is great, and looks like it can push out enough detail to pull off silliness like pushing an SNES game’s output straight to the console. What might be the most impressive element of the library is that while it can blit high res graphics through a terminal emulator with graphical support, it will also work on the basic Linux console, with no graphical system installed, by using some very old tricks. I know what you’re wondering: That’s all well and good, but can it run Doom? Yep. Come back after the break for a demo.
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What NES Development Looks Like On The Apple II

May 20, 2021 by Lewin Day 29 Comments

These days, if you want to code a game for the original Nintendo Entertainment System, it’s about as easy as downloading an assembler, firing up Notepad, and running the ROMs you cook up in any one of a variety of emulators. In the 1980s none of those things existed, and the process was a little more complicated – as demonstrated by [Tyler Barnes] in the video embedded below.

[Tyler] has put together a 40-minute guide on what it takes to get to “Hello World” – or more accurately, a simple pink screen – on the NES, using period-correct hardware. He starts the process by formatting some floppy disks and whipping up some basic assembly code on an Apple IIe, which gets run through the Merlin assembler for the 6502. It’s particularly convenient as the Apple II line and the NES both run the same CPU. From there it’s a case of using a standalone EPROM programmer to verify some appropriately-datecoded chips are empty, before programming them in a special add-on card for the Apple II. From there, the EPROMs are loaded into a cart custom modified with chip sockets, where it can be inserted into a NES for testing.

It’s a tedious process, with just the programming side of things taking on the order of ten to twenty minutes with a few fiddly steps along the way. While there are likely some efficiency gains to be had that were used by studios back in the day, it remains clear that development in this era was a much slower process.

Of course, if you prefer your Nintendo homebrew a couple generations hence, consider getting stuck in on the Nintendo 64. Video after the break.

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Inside The VIC-20

May 19, 2021 by Al Williams 51 Comments

Commodore machines are well-loved around here, but usually when you think Commodore, you think about the Commodore 64, or maybe the PET or Amiga. But the Commodore 64 had an older sister, the VIC 20. This was the first computer to sell a million units and has a lot in common with its better-known successor. The machine was only made for a few years, and [Dubious Engineering] has been restoring one over a few videos. In the video below, he opens it up for a look inside, among other things.

If you want to get straight to the opening, you’ll need to fast forward about 5 and a half minutes. The keyboard pulls off and a nice old-fashioned set of cables made from individual wires connect to the skinny main board with all the smarts on it. No ribbon cables or flex PCBs!

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