Need A Tiny CRT? Karaoke Might Just Help

July 31, 2018 by Lewin Day 30 Comments

[Brett] is working on a video installation, and for the past few months, has been trying to get his hands on tiny CRTs any way he can. After initially coming up short, he happened across a karaoke machine from 2005, and got down to work.

Karaoke machines of this vintage are typically fairly low-rent affairs, built cheaply on simple PCBs. [Brett] found that the unit in question was easy to disassemble, having various modules on separate PCBs joined together with ribbon cables and headers. However, such machines rarely have video inputs, as they’re really only designed to display low-res graphics from CD-G format discs.

While investigating the machine, initial research online proved fruitless. In the end, a close look at the board revealed just what [Brett] was looking for – a pin labeled video in! After throwing in a Raspberry Pi Zero and soldering up the composite output to the karaoke machine’s input pin, the screen sprung to life first time! This initial success was followed by installing a Raspberry Pi 3 for more grunt, combined with a Screenly install – and a TRS adapter the likes of which we’ve never seen before. This allows video to be easily pushed to the device remotely over WiFi. [Brett] promises us there is more to come.

Karaoke is a sparse topic in the Hackaday archives, but we’ve seen a couple builds, like this vocal processor. If you’ve got the hacks, though? You know where to send ’em.

Xbox Needs No TV

February 11, 2018 by Bryan Cockfield 12 Comments

If you want a custom video game system, you could grab a used computer, throw an emulator on it, and build yourself a custom arcade cabinet. On the other hand, if you’d rather not deal with emulators, you can always use a console and modify it into your own tiny arcade cabinet using the original hardware. That’s what the latest project from [Element18592] does, using an Xbox 360 Slim and a small LCD screen to make a mini-arcade of sorts.

The build uses a 7″ TFT LCD and a Flexible Printed Circuit (FPC) extension board. The screen gets 12V power from the Xbox and another set of leads are soldered directly to the composite output on the motherboard. The project also makes use of a special switch which can enable or disable the built-in monitor and allow the Xbox to function with a normal TV or monitor.

Admittedly, he does point out that this project isn’t the most practical to use. But it is still a deceptively simple modification to make to the Xbox compared to some of the more complicated mods we’ve seen before. The fact that almost anyone could accomplish this with little more than some soldering is an impressive feat in the world of console mods.

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Chasing The Electron Beam At 380,000 FPS

January 29, 2018 by Adam Fabio 20 Comments

Analog TV is dead, but that doesn’t make it any less awesome. [Gavin and Dan], aka The Slow Mo Guys recently posted a video about television screens. Since they have some incredible high-speed cameras at their disposal, we get to see the screens being drawn, both on CRT and more modern LCD televisions.

Now we all know that CRTs draw one pixel at a time, drawing from left to right, top to bottom. You can capture this with a regular still camera at a high shutter speed. The light from a TV screen comes from a phosphor coating painted on the inside of the glass screen. Phosphor glows for some time after it is excited, but how long exactly? [Gavin and Dan’s] high framerate camera let them observe the phosphor staying illuminated for only about 6 lines before it started to fade away. You can see this effect at a relatively mundane 2500 FPS.

Cranking things up to 380,117 FPS, the highest speed ever recorded by the duo, we see even more amazing results. Even at this speed, quite a few “pixels” are drawn each frame. [Gavin] illustrates that by showing how Super Mario’s mustache is drawn in less than one frame of slow-mo footage. You would have to go several times faster to actually freeze the electron beam. We think it’s amazing that such high-speed analog electronics were invented and perfected decades ago.

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Let There Be Automated Blinds!

December 4, 2017 by James Hobson 13 Comments

More than once a maker has wanted a thing, only to find it more economical to build it themselves. When your domicile has massive windows, closing what can feel like a mile of blinds becomes a trial every afternoon — or every time you sit down for a movie. [Kyle Stewart-Frantz] had enough of that and automated his blinds.

After taking down and dismantling his existing roller blinds, he rebuilt it using 1-1/4 in EMT conduit for the blinds’ roll to mount a 12V electric shade kit within — the key part: the motor is remote controlled. Fitting it inside the conduit takes a bit of hacking and smashing if you don’t want to or can’t 3D print specific parts. Reattaching the roller blind also takes a fair bit of precision lest they unroll crooked every time. He advises a quick test and fit to the window before moving on to calibrating and linking all your blinds to one remote — unless you want a different headache.

Now, to get Alexa to do your bidding.

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Embiggen Your Eclipse 2017 Experience With A Sun Funnel

August 19, 2017 by Dan Maloney 7 Comments

As exciting as Eclipse 2017 is going to be this Monday, for some folks it might appear a bit — underwhelming. Our star only occupies about half a degree of the sky, and looking at the partial phase with eclipse glasses might leave you yearning for a bigger image. If that’s you, you’ll need to build a sun funnel for super-sized eclipse fun.

[Grady] at Practical Engineering is not going to be lucky enough to be within the path of totality, but he is going to be watching the eclipse with a bunch of school kids. Rather than just outfitting his telescope with a filter and having the kids queue up for a quick peek, he built what amounts to a projection screen for the telescope’s eyepiece. It’s just a long funnel, and while [Grady] chose aluminum and rivets, almost any light, stiff material will do. He provides a formula for figuring out how long the funnel needs to be for your scope, along with plans for laying out the funnel. We have to take exception with his choice of screen material — it seems like the texture of the translucent shower curtain might interfere with the image a bit. But still, the results look pretty good in the video below.

Eclipse 2017 is almost here! How are you planning to enjoy this celestial alignment? By proving Einstein right? By studying radio propagation changes? Or just by wearing a box on your head? Sound off in the comments.

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Dedicated Button For Toggling Screens

August 5, 2017 by Lewin Day 25 Comments

Anyone who regularly presents to an audience these days has known the pain of getting one’s laptop to work reliably with projection hardware. It’s all the more fraught with pain when you’re hopping around from venue to venue, trying desperately to get everything functioning on a tight schedule. [Seb] found that the magic keystrokes they used to deal with these issues no longer worked on the Macbook Pro Touchbar, and so a workaround was constructed in hardware.

The build itself is simple – an Adafruit Trinket serves as the brains, with a meaty 12mm tactile button used for input. The Trinket emulates a USB keyboard and sends the Cmd-F1 keypress to the computer when the button is pressed. The button’s even mounted in a tidy deadbugged fashion.

While it’s not at all complicated from a build standpoint, the key to this project is that it’s a great example of using the tools available to solve real-life problems. When you’re in a rush with 300 people waiting for your talk to start, the last thing you need to be worrying about is a configuration issue. [Seb] now has a big red button to mash to get out of trouble and get on with the job at hand. It does recall this much earlier hack for emulating a USB keyboard with an Arduino Uno or Mega. It’s a useful skill to have!

Hacking Touch Screens To Count Pulses

July 9, 2017 by Inderpreet Singh 5 Comments

Heart rate sensors available for DIY use employ photoplethysmography which illuminates the skin and measures changes in light absorption. These sensors are cheap, however, the circuitry required to interface them to other devices is not. [Petteri Hyvärinen] is successfully investigating the use of capacitive touchscreens for heart rate sensing among other applications.

The capacitive sensor layer on modern-day devices has a grid of elements to detect touch. Typically there is an interfacing IC that translates the detected touches into filtered digital numbers that can be used by higher level applications. [optisimon] first figured out a way to obtain the raw data from a touch screen. [Petteri Hyvärinen] takes the next step by using a Python script to detect time variations in the data obtained. The refresh rate of the FT5x06 interface is adequate and the data is sent via an Arduino in 35-second chunks to the PC over a UART. The variations in the signal are very small, however, by averaging and then using the autocorrelation function, the signal was positively identified as a pulse.

A number of applications could benefit from this technique if the result can be replicated on other devices. Older devices could possibly be recycled to become low-cost medical equipment at a fraction of the cost. There is also the IoT side of things where the heart-rate response to media such as news, social media and videos could be used to classify content.

Check out our take on the original hack for capacitive touch imaging as well as using a piezoelectric sensor for the same application.