[Pekka] set himself up with quite the challenge – use an oscilloscope screen to display Quake in realtime – could it even be done? Old analog scope screens are just monochromatic CRTs but they are designed to draw waveforms, not render graphics.
Over the years Hackaday has tracked the evolution of scope-as-display hacks: Pong, Tetris, vector display and pre-rendered videos. Nothing that pushed boundaries quite like this.
[Pekka]’s solution starts off the same as many others, put the scope in X-Y mode and splice up your headphone cable – easy. He then had to figure out some way to create an audio signal that corresponded to the desire image. The famous “Youscope” example demos this, but that demo is pre-rendered. [Pekka] wanted to play Quake in realtime on the scope itself, not just watch a recording.
With only so much bandwidth available using a soundcard, [Pekka] figured he could draw a maximum of about a thousand lines on screen at a time. The first headache was that all of his audio cards had low-pass filters on them. No way around it, he adjusted his ceiling accordingly. ASIO and PortAudio were his tools of choice to create the audio on the fly from a queue of XY lines given.
To tell his audio engine what lines to draw, he solicited Darkplaces – an open source Quake rendering engine – and had it strip polygons down to the bare minimum. Then he had to whip out the digital hedge trimmers and continue pruning. This writeup really cannot do justice to all the ingenious tricks used to shove the most useful data possible through a headphone jack. If this kind of thing interests you at all, do yourself a favor and check out his well-illustrated project log.
In the end [Pekka] was not entirely happy with the results. The result is playable, but only just barely. The laptop struggles to keep it simple enough, the soundcard struggles to add enough detail and the scope struggles to display it all quickly enough. At the very least it sets the bar extraordinarily high for anyone looking to one-up him using this method. There is only so much water that can be squeezed from a rock.
See the video below of [Pekka] playing the first level of Quake.
Continue reading “Ultimate Oscilloscope Hack – Quake in Realtime”
The Amazon Fire TV is Amazon’s answer to all of the other streaming media devices on the market today. Amazon is reportedly selling these devices at cost, making very little off of the hardware sales. Instead, they are relying on the fact that most users will rent or purchase digital content on these boxes, and they can make more money in the long run this way. In fact, the device does not allow users to download content directly from the Google Play store, or even play media via USB disk. This makes it more likely that you will purchase content though Amazon’s own channels.
We’re hackers. We like to make things do what they were never intended to do. We like to add functionality. We want to customize, upgrade, and break our devices. It’s fun for us. It’s no surprise that hackers have been jail breaking these devices to see what else they are capable of. A side effect of these hacks is that content can be downloaded directly from Google Play. USB playback can also be enabled. This makes the device more useful to the consumer, but obviously is not in line with Amazon’s business strategy.
Amazon’s response to these hacks was to release a firmware update that will brick the device if it discovers that it has been rooted. It also will not allow a hacker to downgrade the firmware to an older version, since this would of course remove the root detection features.
This probably doesn’t come as a surprise to most of us. We’ve seen this type of thing for years with mobile phones. The iPhone has been locked to the Apple Store since the first generation, but the first iPhone was jailbroken just days after its initial release. Then there was the PlayStation 3 “downgrade” fiasco that resulted in hacks to restore the functionality. It seems that hackers and corporations are forever destined to disagree on who actually owns the hardware and what ownership really means. We’re locked in an epic game of cat and mouse, but usually the hackers seem to triumph in the end.
You will never see every episode of Doctor Who, and that’s not because viewing every single episode would require a few months of constant binging. Many of the tapes containing early episodes were destroyed, and of the episodes that still exist, many only live on in tele-recordings, black and white films of the original color broadcast.
Because of the high-resolution of these tele-recordings, there are remnants of the PAL color-coding signal hidden away. [W.A. Steer] has worked on PAL decoding for several years, and figured if anyone could recover the color from these tele-recordings, he could.
While the sensors in PAL video cameras are RGB, a PAL television signal is encoded as luminance, Y (R+G+B), U (Y-B), and V (Y-R). The Y is just the black and white picture, and U and V encode the amplitude of two subcarrier signals. These signals are 90 degrees out of phase with each other (thus Phase Alternating Line), and displaying them on a black and white screen reveals a fine pattern of ‘chromadots’ that can be used to extract the color.
The Cairo hackerspace needed a projector for a few presentations during their Internet of Things build night, and of course Friday movie night. They couldn’t afford a real projector, but these are hackers. Of course they’ll be able to come up with something. They did. They found an old slide projector made in West Germany and turned it into something capable of displaying video.
The projector in question was a DIA projector that was at least forty years old. They found it during a trip to the Egyptian second-hand market. Other than the projector, the only other required parts were a 2.5″ TFT display from Adafruit and a Nokia smartphone.
All LCDs are actually transparent, and if you’ve ever had to deal with a display with a broken backlight, you’ll quickly realize that any backlight will work, like the one found in a slide projector. By carefully removing the back cover of the display, the folks at the Cairo hackerspace were able to get a small NTSC display that would easily fit inside their projector.
After that, it was simply a matter of putting the LCD inside the display, getting the focus right, and mounting everything securely. The presentations and movie night were saved, all from a scrap heap challenge.
[eN0Rm’s] Raspberry Pis are much more than just another brick in the wall. He’s used the popular embedded Linux platform to build several small rear projection screens in a brick wall (Imgur link). Brick shaped metal enclosures were mortared into the wall of the building. Each rear projection screen is illuminated by a DLP projector which sits inside the metal enclosure. The Raspberry Pis sit on a shelf below all this. The bricks are in a building in the Aker Brygge section of Oslo, Norway, and show historical facts and short videos about the local area.
[eN0Rm] could have used a PC for this task, the price for a low-end PC with a few graphics cards probably wouldn’t have been much more expensive than several Raspberry Pi’s with cases. However, this system has to just work, and a PC would represent a single point of failure. Even if one Raspberry Pi goes down, the others will continue running.
The current installation is rather messy, but it’s just a test setup. [eN0Rm] has already been taken to task for the lack of cable management in his Reddit thread. As [eNoRm] says – first get it working, then make it pretty.
[Ioannis] is like anyone else who has a quadcopter or other drone. Eventually you want to sit in the cockpit instead of flying from the ground. This just isn’t going to happen at the hobby level anytime soon. But the next best option is well within your grasp. Why not decouple your eyes from your body by adding a first-person video to your quad?
There are really only four main components: camera, screen, and a transceiver/receiver pair to link the two. [Ioannis] has chosen the Sony Super HAD CCTV camera which provides excellent quality at the bargain basement price of just $25 dollars. A bit of patient shopping delivered a small LCD screen for just $15. The insides have plenty of room as you can see. [Ioannis] connected the screen’s native driver board up to the $55 video receiver board. To boost performance he swapped out the less-than-ideal antenna for a circular polarized antenna designed to work well with the 5.8 GHz radio equipment.
It seems that everything works like a dream. This all came in under $100 which is half of what some other systems cost without a display. Has anyone figured out a way to connect a transmitter like this to your phone for use with Google Cardboard?
The world of drones and FPV remote-controlled aircraft is rapidly expanding, airframes are getting bigger, and the demand for even cooler AV gear is higher than ever. [elad] got his hands on a Sony block camera that is able to zoom in on a scene – great if you want to get close to the action while still flying a safe distance away. Controlling the zoom on these cameras is usually done through RS232, but [elad] made it work with an RC transmitter.
The camera [elad] is using is a Sony FCB-EX11D block camera with a standard SD resolution sensor. This camera has 10x optical zoom, making it a great solution to aerial surveillance, the only problem being the RS232 connection and the VISCA protocol. [elad] used an Arduino to listen in on the elevator channel from an RC receiver, translating that to something the camera will understand. The result is a controllable zoom on a camera that could easily take to the skies.
The entire camera package, with Arduino and electronics included, weighs in at about 100 grams. That’s about the same as a GoPro, and would fit perfectly on a camera gimbal. The only problem is getting a transmitter with enough channels or someone else to operate the camera while flying. Video below.
Continue reading “Controlling a Block Camera with an RC Transmitter”