Old-school handheld gaming platforms have a certain charm, but it’s fair to say that their relatively tiny screens don’t lend themselves to wider viewing. This presented a problem to [uXe] who wanted to display Arduboy games on the big screen, so he took a MyStorm BlackIce FPGA board and created a converter that emulates a SSD1306 OLED display and has a VGA output.
Having proved the viability of the idea, it was ported to a dedicated PCB with onboard ancillaries such as a level shifter for a 5 volt input. In an exciting twist, with a few modifications it’s also emulated a GameBoy screen, allowing full-sized playable games from that platform too. But the power of this hack isn’t relegated to gaming. SSD1306 is just one of a few different common standards for embedded displays. The FPGA work in this project is the blueprint for building a VGA adapter for any number of display replacements. We’d love to see an HD44780 mod of this!
The result as you can see in the video below the break is very much more in the spirit of the OLED than an HD immersive experience. But it does have a very pleasing air of an older arcade machine about it.
Several projects starting on a MyStorm BlackIce board have made it here in the past. Pretty memorable is the BBC Micro clone using one.
The Asus Tinker Board is one of the quiet achievers of the powerful single board computer market. A Raspberry Pi form factor with a significantly more powerful processor, more memory, faster networking, and Asus build quality. In hardware terms it leaves many of the other Pi competitors in the dust. If the Tinker Board has a problem though it is the same one that affects so many otherwise promising offerings, that its software support isn’t as strong as the fruity computer from Cambridge. When you buy a Pi it’s Raspbian that makes it a wise purchase, along with the huge community support that surrounds it.
An interesting development on that front comes courtesy of [Justin], who tells us that the sources have been released for the Tinkerboard flavour of Android. The community have put in the work on the board’s Linux distro, but the Android side hasn’t had the same opportunity. This step makes the Tinker Board a significantly more interesting choice for custom Android development, as unlike some of its competitors for which only precompiled builds are available it puts a bespoke Android build in the hands of its developers.
We like the Tinker Board here at Hackaday. We first reviewed it when the boards became available, but later found that they had reached the market in error before Asus had a stable operating system. We therefore returned with another review six months later, and found it to be a credible Raspberry Pi alternative saved by its band of enthusiasts who have filled in for any of its software shortcomings.
If you are a devotee of audiophile-quality analogue hi-fi, switching between sources simply can not be done through a solid-state device. Only physical switches will do because they come without the risk of extra noise or distortion that their silicon equivalents might bring.
That is the philosophy that lies behind [Skrodahl]’s relay-based audio switching board, which boasts 5 high-quality relays each handling a stereo input, with their control passed either to a rotary switch or to an ESP32 module. The ground connections on audio and switching sides are isolated from each other to avoid transient noise finding its way to the speakers.
You might think that an audio switching board is a very simple device indeed and thus not worthy of Hackaday’s attention, but it’s surprisingly easy to make a mess of a module like this one and they have put in some effort to avoid the pitfalls. The metal-can version of the switching transistors seems a little overkill, but fancy audio is a funny business.
If the ESP isn’t your bag, we’ve brought you another relay based audio switcher in the past that used an Atmel chip.
Amateur radio is an extremely broad church when it comes to the numerous different activities that it covers. Most of the stories featuring radio amateurs that we cover here have involved home-made radios, but that represents a surprisingly small subset of licence holders.
One activity that captivates many operators is grid square collecting. The map is divided into grid squares, can you make contact with all of them? Land-based squares in Europe and North America are easy, those in some more sparsely populated regions a little less so, and some squares out in the ocean are nigh-on impossible. As an attempt to solve this problem, the Jupiter Research Foundation Amateur Radio Club have put an HF transceiver and associated electronics in a WaveGlider autonomous seagoing vehicle. The idea is that it will traverse the ocean, and you can work it, thus getting the contact you require to add those rarest of grid squares to your list.
The transceiver in question is a commercial portable one, an Elecraft KX3, and the brain of the payload is a Raspberry PI. It’s operating the FT8 mode, and will respond to a call on 14074 kHz in an automated fashion (Or it would, were its status page not telling us that it is offline due to power issues). It’s currently somewhere in the Pacific ocean, having been at sea now for a couple of months.
We spotted this through a spirited online discussion as to whether working an automated station is really a proper contact at all, with one amateur commenting that it might be a way for him to keep on going post mortem. But the ethics of the contact aside, it’s an extremely interesting project and one we hope eventually will come back online.
The business card is an odd survivor from the past, when you think about it. When a salesman in a Mad Men style suit stepped out of his Studebaker and walked past a room full of typists to the boss’s wood-paneled office, he would have handed over a card as a matter of course. It would get filed away in the Rolodex.
These days, making your card stand out from the crowd of print-shop specials has become an art form. In our community this extends to cards with integrated electronics, such as this one with a persistence-of-vision display driven by an ATtiny from [James Cochrane], shown in the video below. It’s by no means the first such card, but he takes us through its design and construction in great detail which makes the video below the break worth a look. If you have never made a toner transfer PCB for example, you can see how his was made.
He makes the point that while a POV spinner needs only to display in one direction, a card has to be waved back and forth. Thus it needs to change the direction of its display, and needs a tilt sensor to activate this. His construction method uses through-hole components, but is surface mount in that they are soldered to the top surface of the board. The result is a rather attractive POV card that maybe isn’t something you’d hand out to all and sundry, but perhaps that’s not the point.
You might be reading this six minutes early. Assuming that the Hackaday editors have done their job, this article should have appeared in your feed right on the half-hour. We have a set schedule to keep you supplied with the tastiest of hardware hacks and news. For some of you though perhaps there has been a treat, you’ve seen it and all the other stories six minutes early.
Think for a minute of a modern car on a hot day. When you turn on the air conditioning you will hear a slight dip in the engine revs as it accommodates the extra load. So it is with an alternating current power grid; a simple example is a power station supplying a city. In periods such as cold nights when the demands of the city go up, the result would be that the power station needs to work harder to satisfy it, and until that happens there would be a slight dip in its line frequency. Power grids compensate for this by increasing and decreasing the available generating capacity in real time, maintaining a mean frequency such that the “grid time” of a clock controlled by it matches an atomic clock as closely as possible over time.
It is at this point we leave the realm of electrical engineering and enter that of international politics, normally something far removed from Hackaday’s remit. It is fair to say that the history between Serbia and Kosovo is extremely delicate, and to understand some of the context of this story you should read about the war at the end of the 1990s. After the conflict the Serbian-majority region of what is now Kosovo refused to pay the Kosovan utility for its electricity, eventually leading to the Kosovans refusing to pay for that region’s share of the power received by Kosovo from Serbia. The resulting imbalance between demand and supply was enough to drag the supply frequency down across the whole continent, and though a short-term agreement has been reached the problem still remains on the grid.
Clocks and Mains Frequency
So if you are a continental European and you find yourself six minutes behind your British or American friends, don’t worry. We know that among our readers are people with significant experience in the power generation world, perhaps some of you would like to use your six minutes to give us a bit of insight in the comments. Meanwhile here at Hackaday we maintain an interest in the mechanics of power distribution even if some might say that it is Not A Hack. We’ve taken a look at utility poles, and examined how power grids are synchronised.
As for those slow clocks, the use of mains frequency to keep accurate time is quite brilliant and has been used reliably for decades. Tightly regulating grid frequency means that any clock plugged into an outlet can have the same dead-on accuracy for the cost of a few diodes. These clocks count the zero crossing of the alternating current. There may be moment to moment drifts but the power utility injects or removes cycles over the long term so the sum of crossings is dead on over the course of the day. It’s an interesting phenomenon to experiment with and that’s why we see it in microcontroller projects from time to time.
When designing a microphone assembly the other day, I reached for an electret condenser microphone capsule without thinking. To be strictly accurate I ordered a pack of them, these small cylindrical microphones are of extremely high quality for their relatively tiny price.
It was only upon submitting the order that I had a thought for the first time in my life: Just what IS an electret condenser microphone?
A condenser microphone is easy enough to explain. It’s a capacitor formed from a very thin conductive sheet that functions as the diaphragm, mounted in front of another conductor, usually a piece of mesh. Sound waves cause the diaphragm to vibrate, and these vibrations change the capacitance between diaphragm and mesh.
If that capacitance is incorporated into an RC circuit with a very high impedance and a high voltage is applied, a near constant charge is placed upon it. Since the charge stays constant, changing the capacitance causes a tiny voltage fluctuation that can be retrieved as the audio signal from the microphone. Condenser microphones built in this way can be extremely high quality, but come at the expense of needing a high voltage power supply to supply the charge and an amplifier to buffer and magnify the audio.
Having proved the viability of the idea, it was ported to a dedicated PCB with onboard ancillaries such as a level shifter for a 5 volt input. In an exciting twist, with a few modifications it’s also emulated a GameBoy screen, allowing full-sized playable games from that platform too. But the power of this hack isn’t relegated to gaming. SSD1306 is just one of a few different common standards for embedded displays. The FPGA work in this project is the blueprint for building a VGA adapter for any number of display replacements. We’d love to see an HD44780 mod of this!
