Amiga Now Includes HDMI By Way Of A Raspberry Pi Daughterboard

If you had an Amiga during the 16-bit home computer era it’s possible that alongside the games and a bit of audio sampling you had selected it because of its impressive video capabilities. In its heyday the Amiga produced broadcast-quality graphics that could even be seen on more than a few TV shows from the late 1980s and early 1990s. It’s fair to say though that the world of TV has moved on since the era of Guru Meditation, and an SD video signal just won’t cut it anymore. With HDMI as today’s connectivity standard, [c0pperdragon] is here to help by way of a handy HDMI upgrade that taps into the digital signals direct from the Amiga’s Denise chip.

At first thought one might imagine that an FPGA would be involved, however instead the signals are brought out via a daughterboard to the expansion header of a Raspberry Pi Zero. Just remove the DENISE display encoder chip and pop in the board with uses a long-pinned machined DIP socket to make the connections. The Pi runs software from the RGBtoHDMI project originally created with the BBC Micro in mind, to render pixel-perfect representations of the Amiga graphics on the Pi’s HDMI output. The caveat is that it runs on the original chipset Amigas and only some models with the enhanced chipset, so it seems Amiga 600 owners are left in the cold. A very low latency is claimed, which should compare favourably with some other solutions to the same problem.

This isn’t the first time we’ve seen an HDMI Amiga conversion, but it’s one that’s usable on more than simply the big-box machines.

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Heavy Raspberry Pi User? Keep An HDMI-to-USB Capture Device Around

Here’s a simple tip from [Andy], whose Raspberry Pi projects often travel with him outside the workshop: he suggests adding a small HDMI-to-USB video capture device to one’s¬†Raspberry Pi utility belt. As long as there is a computer around, it provides a simple and configuration-free way to view a Raspberry Pi’s display that doesn’t involve the local network, nor does it require carrying around a spare HDMI display and power supply.

Raspberry Pi’s display, viewed on a Mac as if it were a USB webcam. No configuration required.

The usual way to see a Pi’s screen is to either plug in an HDMI display or to connect remotely, but [Andy] found that he didn’t always have details about the network where he was working (assuming a network was even available) and configuring the Pi with a location’s network details was a hassle in any case. Carrying around an HMDI display and power supply was also something he felt he could do without. Throwing a small HDMI-to-USB adapter into his toolkit, on the other hand, has paid off for him big time.

The way it works is simple: the device turns an HDMI video source into something that acts just like a USB webcam’s video stream, which is trivial to view on just about any desktop or laptop. As long as [Andy] has access to some kind of computer, he can be viewing the Pi’s display in no time.

Many of his projects (like this automated cloud camera timelapse) use the Pi camera modules, so a quick way to see the screen is useful to check focus, preview video, and so on. Doing it this way hit a real sweet spot for him. We can’t help but think that one of these little boards could be a tempting thing to embed into a custom cyberdeck build.

An IMac All-In-One’s New Life

There’s a sleek form factor for desktop computers known as an “all-in-one” that enrobes a computer in a monitor. While the convenience of having all your computing in a neat package has some nice benefits, it comes with an unfortunate downside. Someday the computer inside is going to be old and outdated in comparison to newer machines. While a new OS goes a long way towards breathing life into an old machine, [Thomas] has decided to take the path less travelled and converted an old iMac all-in-one into a discrete monitor.

The iMac in question is the 20″ iMac G5 iSight (A1145) with an LG-Philips LM201W01-STB2 LCD panel. Looking back, [Thomas] would recommend just ordering an LCD driver controller kit from your favourite auction house. But for this particular modification, he decided to do things a little bit more manually and we’re quite glad he did.

Luckily for [Thomas], the panel supports TMDS (which both DVI and HDMI are compatible with). So the next step was to figure out the signalling wires and proper voltages. After some trouble caused by a mislabeled power line on the iMac PCB silk-screen (12v instead of 3.3v), he had all the wires identified and a plan starting to form. The first step was a circuit to trick the inverter into turning on with the help of a relay. The female HDMI plug with a breakout board was added and sticks out through the old firewire port. The minuscule wires in the display ribbon cable to the monitor were separated and soldered onto with the help of [Thomas’] daughter’s microscope. Resistances were checked as HDMI relies on impedance matched pairs. To finish it off, an old tactile toggle switch offers a way to turn the monitor on and off with a solid thunk.

We love seeing old hardware being repurposed for new things. This project nicely complements the iMac G4 Reborn With Intel NUC Transplant we saw earlier this year, as they both try to preserve the form factor while allowing a new computer to drive the display.

True Networked KVM Without Breaking The Bank

For administering many computers at once, an IP KVM is an invaluable piece of equipment that makes it possible to get the job done over the network without having to haul a keyboard, monitor, and mouse around to each computer. The only downside is that they can get pricey, unless of course you can roll one out based on the Raspberry Pi and the PiKVM image for little more than the cost of the Pi itself.

The video linked below shows how to set all of this up, which involves flashing the image and then setting up the necessary hardware. The build shows an option for using HDMI over USB, but another option using the CSI bus would allow for control over options like video resolution and color that a USB HDMI dongle doesn’t allow for. It also makes it possible to restart the computer and do things like configure BIOS or boot from removable media, which is something that would be impossible with a remote desktop solution like VNC.

The creator of PiKVM was mentioned in a previous post about the creation of the CSI bus capture card, and a Pi hat based on this build will be available soon which would include options for ATX controls as well. Right now, though, it’s possible to build all of this on your own without the hat, and is part of what makes the Pi-KVM impressive, as well as its very low cost.

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Motorized Magic Over HDMI

There is a certain warmth that seems to emanate from stereo receivers of the 70s, 80s, and 90s. Despite their large footprint and considerable heft, the soft glow of the indicator lights and solid kerthunk of switches provide a sense of coziness. When [Tom] recently swapped his receiver for a 1970s Pioneer SX-950, he found himself getting up from the couch to adjust the volume when watching TV far too often for his liking. Resolving to do something about it, he added some magic in the form of a motorized volume knob. One of the coolest tricks for stereos was to have a small motor attached to the volume knob so that it could turn the volume up or down via a remote.

The first obstacle came when [Tom] had to forgo the center tap on the potentiometer to get a motorized one. This meant the volume compensation feature would be disabled, which is but a small price to pay for convenience. After scouring the internet, he finally had the part in hand only to discover some troublesome capacitors in the way. The new pot had a rather large motor hanging off the back that the previous one didn’t have. Fortunately, there was a good bit of space between the PCB and the bottom of the chassis, so Tom was able to just flip the capacitors to the underside of the board and bend them on their sides.

The next problem to solve was how to change the volume remotely. IR was considered as well as optical cable control signals. What [Tom] did instead was to implement HDMI CEC (consumer electronics control). CEC was well documented and seemed simple to implement on an ATTINY4313 with the help of a half-H driver. The CEC protocol implemented by [Tom’s] TV seemed to be very sensitive to timing, so an external crystal was used to get more precise timing and additional handshaking was implemented to get the TV to accept the microcontroller as valid. A few fail-safes were added to make sure the motor didn’t burn out if something went wrong with the CEC protocol and a nice enclosure wrapped up the build quite nicely.

We’ve seen CEC implemented before on a PIC 18F87J50, but as a sender of CEC commands not a receiver. [Tom’s] code is available on GitHub and might prove useful if you’re looking to implement CEC on an AVR.

Thanks [Tom] for sending this one in!

An HDMI Monitor From Your Phone

Digital video has proceeded to the point at which we have near-broadcast-quality HD production capabilities in the palm of our hand, and often for a surprisingly affordable price. One area in which the benefits haven’t quite made it to our wallets though is in the field of small HD monitors of the type you might place on top of a camera for filming. It’s a problem noted by [Neon Airship], who has come up with a solution allowing the use of an Android mobile phone as an HDMI monitor. Since many of us will now have a perfectly capable older phone gathering dust, it’s an attractive proposition with the potential to cost very little.

The secret isn’t the most elite of hacks in that it uses all off-the-shelf hardware, but sometimes that isn’t the only reason to be interested in a project such as this one. [Neon] is using an HDMI-to-USB capture card of the type that has recently become available from the usual sources for an astoundingly small sum. When paired with a suitable USB OTG cable, the adapter can be seen by the phone as just another webcam.

We see him try a few webcam viewer apps including one that rather worryingly demands a direct APK download, and the result is a very good quality HDMI monitor atop his camera that really didn’t break the bank. Sometimes the simplest of solutions deliver the most useful of results.

This is something of special interest to those of us who experiment with our own camera form factors.

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Exposing Computer Monitor Side-Channel Vulnerabilities With TempestSDR

Having been endlessly regaled with tales of side-channel attacks and remote exploits, most of us by now realize that almost every piece of gear leaks data like a sieve. Everything from routers to TVs to the power supplies and cooling fans of computers can be made to give up their secrets. It’s scary stuff, but it also sounds like a heck of a lot of fun, and with an SDR and a little software, you too can get in on the side-channel action.

Coming to us via software-defined radio buff [Tech Minds], the video below gives a quick tour of how to snoop in on what’s being displayed on a monitor for almost no effort or expense. The software that makes it possible is TempestSDR, which was designed specifically for the job. With nothing but an AirSpy Mini and a rubber duck antenna, [Tech Minds] was able to reconstruct a readable black and white image of his screen at a range of a few inches; a better antenna and some fiddling might improve that range to several meters. He also shares a trick for getting TempestSDR set up for all the popular SDRs, including SPRplay, HackRF, and RTL-SDR.

Learning what’s possible with side-channel attacks is the key to avoiding them, so hats off to [Tech Minds] for putting together this simple, easy-to-replicate demo. To learn even more, listen to what [Samy Kamkar] has to say about the subject, or check out where power supplies, cryptocurrency wallets, and mixed-signal microcontrollers are all vulnerable.

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