What Else Is An M.2 WiFi Slot Good For?

January 19, 2023 by Maya Posch 23 Comments

Many mainboards and laptops these days come with a range of M.2 slots, with only a subset capable of NVME SSDs, and often a stubby one keyed for ‘WiFi’ cards. Or that’s what those are generally intended to be used for, but as [Peter Brockie] found out when pilfering sites like AliExpress, is that you can get a lot of alternate expansion cards for those slots that have nothing to do with WiFi.

Why this should be no surprise to anyone who knows about the M.2 interface is because each ‘key’ type specifies one or more electrical interfaces that are available on that particular M.2 slot. For slots intended to be used with NVME SSDs, you see M-keying, that makes 4 lanes of PCIe available. The so-called ‘WiFi slots’ on many mainboards are keyed usually for A/E, which means two lanes of PCIe, USB 2.0, I2C and a few other, rather low-level interfaces. What this means is that you can hook up any PCIe or or USB (2.0) peripheral to these slots, as long as the bandwidth is sufficient.

What [Peter] found includes adapter cards that add Ethernet (1 Gb, 2.5 Gb), USB 2.0 ports, SIM card (wireless adapter?), an SFP fiber-based networking adapter, multiple M.2 to 2+ SATA port adapters, tensor accelerator chips (NPUs) and even a full-blown M.2 to x16 PCIe slot adapter. The nice thing about this is that if you do not care about using WiFi with a system, but you do have one of those ports lounging about uselessly, you could put it to work for Ethernet, SFP, SATA or other purposes, or just for hooking up internal USB devices.

Clearly this isn’t a market that has gone unexploited for very long, with a bright outlook for one’s self-designed M.2 cards. Who doesn’t want an FPGA device snuggled in a PCIe x2 slot to tinker with?

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It’s Not Easy Counting Transistors In The 8086 Processor

January 16, 2023 by Maya Posch 15 Comments

For any given processor it’s generally easy to find a statistic on the number of transistors used to construct it, with the famous Intel 8086 CPU generally said to contain 29,000 transistors. This is where [Ken Shirriff] ran into an issue when he sat down one day and started counting individual transistors in die shots of this processor. To his dismay, he came to a total of 19,618, meaning that 9,382 transistors are somehow unaccounted for. What is going on here?

The first point here is that the given number includes so-called ‘potential transistors’. Within a section of read-only memory (ROM), a ‘0’ would be a missing transistor, but depending on the programming of the mask ROM (e.g. for microcode as with a CISC x86 CPU), there can be a transistor there. When adding up the potential but vacant transistor locations in ROM and PLA (programmable logic array) sections, the final count came to 29,277 potential transistors. This is much closer to the no doubt nicely rounded number of 29,000 that is generally used.

[Ken] also notes that further complications here are features such as driver transistors that are commonly found near bond wire pads. In order to increase the current that can be provided or sunk by a pad, multiple transistors can be grouped together to form a singular driver as in the above image. Meanwhile yet other transistors are used as (input protection) diodes or even resistors. All of which makes the transistor count along with the process node used useful primarily as indication for the physical size and complexity of a processor.

Increasing PV Solar Cell Efficiency Through Cooling

January 14, 2023 by Maya Posch 54 Comments

An unavoidable aspect of photovoltaic (PV) solar panels is that they become less efficient when they warm up. [Tech Ingredients] explains in a new video the basic reason for this, which involves the input of thermal energy affecting the semiconductor material. In the subsequent experiment, it is demonstrated how cooling the backside of the panel affects the panel’s power output.

There are commercial solutions that use water cooling on the back of panels to draw heat away from panels, but this still leaves the issues of maintenance (including winter-proofing) and dumping the heat somewhere. One conceivable solution for the latter is to use this heat for a household’s hot water needs. In the demonstrated system a heatsink is installed on the back of the panel, with fans passing cool air over the heatsink fins.

On a 100 Watt PV panel, 10 W was lost from the panel heating up in the sun. After turning on the fans, the panel dropped over 10 °C in temperature, while regaining 5.5 W. Since the installed fans consumed about 3 W, this means that the fans cost no extra power but resulted in increased production. Not only that, but the lower temperatures will in theory extend the panel’s lifetime. Though even with active cooling, even the best of PV panels will need to be replaced after a couple decades.

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Fixing An HP 54542C With An FPGA And VGA Display

January 13, 2023 by Maya Posch 11 Comments

Although the HP 54542C oscilloscope and its siblings are getting on in years, they’re still very useful today. Unfortunately, as some of the first oscilloscopes to switch from a CRT display to an LCD they are starting to suffer from degradation. This has led to otherwise perfectly functional examples being discarded or sold for cheap, when all they need is just an LCD swap. This is what happened to [Alexander Huemer] with an eBay-bought 54542C.

Although this was supposed to be a fully working unit, upon receiving it, the display just showed a bright white instead of the more oscilloscope-like picture. A short while later [Alexander] was left with a refund, an apology from the seller and an HP 54542C scope with a very dead LCD. This was when he stumbled over a similar repair by [Adil Malik], right here on Hackaday. The fix? Replace the LCD with an FPGA and VGA-input capable LCD.

While this may seem counter intuitive, the problem with LCD replacements is the lack of standardization. Finding an 8″, 640×480, 60 Hz color LCD with a compatible interface as the one found in this HP scope usually gets you salvaged LCDs from HP scopes, which as [Alexander] discovered can run up to $350 and beyond for second-hand ones. But it turns out that similar 8″ LCDs are found everywhere for use as portable displays, all they need is a VGA input.

Taking [Adil]’s project as the inspiration, [Alexander] used an UPduino v3.1 with ICE40UP5K FPGA as the core LCD-to-VGA translation component, creating a custom PCB for the voltage level translations and connectors. One cool aspect of the whole system is that it is fully reversible, with all of the original wiring on the scope and new LCD side left intact. One niggle was that the scope’s image was upside-down, but this was fixed by putting the new LCD upside-down as well.

After swapping the original cooling fan with a better one, this old HP 545452C is now [Alexander]’s daily scope.

Maxing Out Your MacIntosh With A 4 MB Memory Stick Kit

January 12, 2023 by Maya Posch 22 Comments

One fun aspect of retrocomputing is that you get to max out all aspects of these systems without having to take out a bank loan, as tended to be the case when these systems were new. Less fun is that decades after systems like the Apple MacIntosh SE/30 were last sold, the 30-pin SIMMs that form the expandable RAM for these systems has become rather scarce. This has led many to make their own SIMM PCBs, including [Kay Koba] with a PCB for 4 MB SIMMs along with information on which memory and parity ICs are suitable for these SIMMs.

For systems like the MacIntosh SE/30 with 8 30-pin memory slots, the maximum capacity is 128 MB, but this comes with many gotchas due to its ROM being ’32-bit dirty’. While this can be circumvented by swapping in a ROM from a later MacIntosh variant, the less invasive way is to enable the MODE32 system extension and install eight 4 MB SIMMs for a total of 32 MB RAM. RAM chips for such 30-pin SIMMs can be scavenged from the far more common 72-pin SIMMs, along with any old new stock one may come across.

These 4 MB SIMM PCBs are offered for sale by [Kay] with optionally the SMD components (capacitors, resistors and LED) included in the package. The original PCB card edge design is credited to work by [Zane Kaminski] whose GitHub profile also leads to e.g. this 30-pin SIMM project.

Have you modded your MacIntosh or other retro system yet to the maximum RAM and storage limits?

Building A Homemade Ambient Pressure Submarine

January 11, 2023 by Maya Posch 27 Comments

About two years ago, [Hyperspace Pirate] set to work on building his own two-seater submarine, because who doesn’t want to have a submarine when you have just moved to Florida? In the linked video (also attached below), he describes the reasoning behind the submarine design. Rather than going with a fully sealed submarine with ambient pressure inside and a hull that resists the crushing forces from the water, he opted to go for a semi-wet ambient pressure design.

What this essentially entails is a fancy equivalent of an old-school diving bell: much as the name suggests, these are sealed except for the bottom, which allows for water to enter and thus equalize the pressure. Although this has the distinct disadvantage of being not dry inside (hence the semi-wet), it does mean that going for a dive is as easy as letting the water in via the bottom hole, and to resurface only a small amount of air injected into two ballast tanks and a pump are all that are required.

So far this submarine has survived a few test runs, which uncovered a number of issues, but diving and resurfacing seems to be going pretty smoothly now, which is definitely a massive plus with a submarine.

(Thanks to [Drew] for the tip!)

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The Intricacies Of Creating Fuel For Nuclear Reactors

January 10, 2023 by Maya Posch 51 Comments

All nuclear fission power reactors run on fuel containing uranium and other isotopes, but fueling a nuclear reactor is a lot more complicated than driving up to them with a dump truck filled with uranium ore and filling ‘er up. Although nuclear fission is simple enough that it can occur without human intervention as happened for example at the Oklo natural fission reactors, within a commercial reactor the goal is to create a nuclear chain reaction that targets a high burn-up (fission rate), with an as constant as possible release of energy.

Each different fission reactor design makes a number of assumptions about the fuel rods that are inserted into it. These assumptions can be about the enrichment ratio of the fissile isotopes like U-235, the density of individual fuel pellets, the spacing between the fuel rods containing these pellets, the configuration of said fuel rods along with any control, moderator and other elements. and so on.

Today’s light water reactors, heavy water reactors, fast neutron reactors, high temperature reactors and kin all have their own fuel preferences as a result, with high-assay low-enriched (HALEU) fuel being the new hot thing for new reactor designs. Let’s take a look at what goes into these fuel recipes.

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