This Is Not A Laptop, It’s A KVM Combo

August 19, 2024 by 65 Comments

A spare monitor and keyboard are handy things to have around, but they’re a bit of a hassle. They are useful for hardware development, plugging in to headless servers, or firing up a Raspberry Pi or similar single-board computer (SBC). If that’s something you do and portability and storage space are important to you, then you may be interested in the CrowView Note.

I got an opportunity to test and provide feedback on an early version of this unusual device, which is functionally a portable spare monitor plus keyboard (and touchpad) without the bulk and extra cables. Heck, it’s even giving me ideas as the guts of a Cyberdeck build. Let’s take a look.

What It Is

It really looks like a laptop, but it’s actually a 14″ 1920 x 1280 monitor and USB keyboard in a laptop form factor.

There is also an integrated trackpad, speakers and mic, and a rechargeable battery. That makes it capable of providing its own power, and it can even function as a power bank in a pinch. There’s an HDMI input on one side, and on the other is a full-featured USB-C port that accepts video input via the DisplayPort altmode.

Pictured here is a Raspberry Pi 5 with optional PCB adapter to eliminate cables. The three ports (HDMI in, USB-C 5 V out, and USB-A for peripherals) provide all the board needs.

The CrowView Note is a pretty useful device for a workbench where one is often plugging hardware in for development or testing, because there’s no need to manage a separate monitor, keyboard, and mouse.

It is not a laptop, but attaching an SBC like a Raspberry Pi makes it act like one. The three ports conveniently located on the left-hand side (HDMI in, USB-C out for power to the SBC, and USB-A in for peripherals like keyboard and trackpad) are all that are needed in this case. Elecrow offers a “cable eliminator” PCB adapters to make the process of connecting a Raspberry Pi 5 or a Jetson Nano as simple as possible. The result is something that looks and works just like a laptop.

Well, almost. The SBC will still be a separate piece of hardware, whether connected by cables or by one of Elecrow’s PCB adapters. The result is OK for bench work, but especially in the case of the PCB adapter, not particularly rugged. Still, it’s a nice option and makes working on such boards convenient and cable-free.

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Building A Paper Tape Reader To Read Bytes

August 19, 2024 by 19 Comments

Over at the Usagi Electric farm, [David Lovett]’s custom 1-bit, vacuum tube-based computer (UEVTC for short) has been coming along well the past years, matching and exceeding the Motorola MC14500B 1-bit industrial control unit (ICU) that it is heavily inspired by. What is still missing, however, is a faster way to get data into the computer than manually toggling switches. The obvious choice is to make a (punched) paper tape reader, but how does one go about this, and what options exist here? With a few historical examples as reference and the tape reader on the impressive 1950s Bendix G-15 which [David] happens to have lounging around, [David] takes us in a new video through the spiraling complexity of what at first glance seems like a simple engineering challenge.

Photodiodes in the tape reader of the Bendix G-15. (Credit: David Lovett, Usagi Electric)

Punched paper tape saw significant use alongside punched paper cards and magnetic tape, and despite their low bit density, if acid-free paper (or e.g. mylar) is used, rolls of paper tape should remain readable for many decades. So how to read these perforations in the paper? This can be done mechanically, or optically, with in both case the feedrate an important consideration.

Right off the bat the idea of a mechanical reader was tossed out due to tape wear, with [David] digging into his stack of photodetector tubes. After looking at a few rather clunky approaches involving such tubes, the photodiodes in the Bendix G-15’s tape reader were instead used as inspiration for a design. These are 1.8 mm diameter photodiodes, which aren’t super common, but have the nice property that they align exactly with the holes in the paper tape.

This left building a proof-of-concept on a breadboard with some incandescent bulbs and one of the photodiode to demonstrate that a valid logic signal could be produced. This turned out to be the case, clearing the construction of the actual tape reader, which will feature in upcoming videos.

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An Open Source 6kW GaN Motor Controller

August 19, 2024 by 35 Comments

We don’t know how you feel when designing hardware, but we get uncomfortable at the extremes. High voltage or current, low noise figures, or extreme frequencies make us nervous.  [Orion Serup] from CrabLabs has been turning up a few of those variables and has created a fairly beefy 3-phase motor driver using GaN technology that can operate up to 80V at 70A. GaN semiconductors are a newer technology that enables greater power handling in smaller packages than seems possible, thanks to high electron mobility and thermal conductivity in the material compared to silicon.

The KiCAD schematic shows a typical high-power driver configuration, broken down into a gate pre-driver, the driver itself, and the following current and voltage sense sub-circuits. As is typical with high-power drivers, these operate in a half-bridge configuration with identical N-channel GaN transistors (specifically part EPC2361) driven by dedicated gate drivers (that’s the pre-driver bit) to feed enough current into the device to enable it to switch quickly and reliably.

The design uses the LM1025 low-side driver chip for this task, as you’d be hard-pushed to drive a GaN transistor with discrete components! You may be surprised that the half-bridge driver uses a pair of N-channel devices, not a symmetric P and N arrangement, as you might use to drive a low-power DC motor. This is simply because, at these power levels, P-channel devices are a rarity.

Why are P-channel devices rare? N-channel devices utilise electrons as the majority charge carrier, but P-channel devices utilise holes, and the mobility of holes in GaN is very low compared to that of electrons, resulting in much worse ON-resistance in a P-channel and, as a consequence, limited performance. That’s why you rarely see P-channel devices in a circuit like this.

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Machining Copper From Algaecide

August 18, 2024 by 5 Comments

We love it when we find someone on the Internet who has the exact same problem we do and then solves it. [Hyperspace Pirate] starts a recent video by saying, “Oh no! I need to get rid of the algae in my pond, but I bought too much algaecide. If only there were a way to turn all this excess into CNC machined parts.” OK, we’ll admit that we don’t actually have this problem, but maybe you do?

Algaecide is typically made with copper sulfate. There are several ways to extract the copper, and while it is a little more expensive than buying copper, it is cost-competitive. Electrolysis works, but it takes a lot of power and time. Instead, he puts a more reactive metal in the liquid to generate a different sulfate, and the copper should precipitate out.

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Quantum Sensor Uses Synthetic Diamond

August 18, 2024 by 3 Comments

Diamonds are nearly perfect crystals, but not totally perfect. The defects in these crystals give the stones their characteristic colors. But one type of defect, the NV — nitrogen-vacancy — center, can hold a particular spin, and you can change that spin with the correct application of energy. [Asianometry] explains why this is important in the video below.

Interestingly, even at room temperature, an NV center stays stable for a long time. Even more importantly, you can measure the spin nondestructively by detecting light emissions from the center.

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Hackaday Links: August 18, 2024

August 18, 2024 by 4 Comments

They’re back! The San Francisco autonomous vehicle hijinks, that is, as Waymo’s fleet of driverless cars recently took up the fun new hobby of honking their horns in the wee hours of the morning. Meat-based neighbors of a Waymo parking lot in the South Market neighborhood took offense at the fleet of autonomous vehicles sounding off at 4:00 AM as they shuffled themselves around in the parking lot in a slow-motion ballet of undetermined purpose. The horn-honking is apparently by design, as the cars are programmed to tootle their horn trumpets melodiously if they detect another vehicle backing up into them. That’s understandable; we’ve tootled ourselves under these conditions, with vigor, even. But when the parking lot is full of cars that (presumably) can’t hear the honking and (also presumably) know where the other driverless vehicles are as well as their intent, what’s the point? Luckily, Waymo is on the case, as they issued a fix to keep the peace. Unfortunately, it sounds like the fix is just to geofence the lot and inhibit honking there, which seems like just a band-aid to us.

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Zero-dimensional PONG game built on a perfboard.

2024 Tiny Games Contest: Coming At Ya With Zero-Dimensional PONG

August 18, 2024 by 5 Comments

A decade is a long time to carry around a project idea in your head. Fortunately, the Tiny Games Contest happens to coincide with [Senile Data Systems]’s getting back into ATMega programming, so they can finally make their zero-dimensional PONG dreams come true (and have the chance at great prizes, too, of course).

If you don’t already get what’s going on here, zero-dimensional PONG takes 1D PONG and turns it on the short side. Imagine the light coming toward you, then moving away toward your opponent, and you have the basic idea. So, how is this done? Pulse-width modulation controls the brightness of the LED, and, well, you have to be pretty fast, although there is a small margin for the inevitable error.

In the video after the break, you can watch [SDS] play themselves using a red/green LED. Player one must press the button when red is fully lit and green is off, and player two goes when green is fully lit and red is off. The cool thing is that this game uses sockets, so it can use any LED. There are nine difficulty levels to control the PWM speed,  so one can really test one’s reaction time.

If you want to build one of these, you’ll need an ATtiny2313 or something similar, a couple of buttons, a display, and the optional but fun buzzer. The well-commented code is available through [Senile Data Systems]’s site.

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