Visualizing How Signals Travel In A PCB

If you play with high speed design for long enough, eventually you’re going to run into clock skew and other weird effects. [Robert Feranec] recently ran into this problem and found an interesting solution to visualizing electric fields in a PCB.

A word of warning before we dig into this, for most of the projects we see on Hackaday something like this is completely superfluous. There aren’t many people dealing with high speed interfaces here, and there aren’t many people dealing with 100 Gigabit per second data links, period. That said, it’s not unheard of, and at the very least it’s interesting to look at.

The basics of this video is simulating the signals visually in a differential pair on a (virtual) printed circuit board. The software for this is Simbeor, and [Robert] talked to the founder of the company behind this software after watching a video on simulating electric fields in differential traces. This software does what it says, and is a great illustration of why differential pairs must have the same length.

While this might not be for everyone, it is a fantastic visualization of signals in high-speed design that goes above and beyond what you would expect from a Spice simulation. Even if you’re not doing high-speed design, you may someday and it’s never too soon to get an intuitive understanding of how electrons work.

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Drag And Drop Files On Select Arduino Boards

Historically, getting files on to a microcontroller device was a fraught process. You might have found yourself placing image data manually into arrays in code, or perhaps repeatedly swapping SD cards in and out. For select Arduino boards, that’s no longer a problem – thanks to the new TinyUSB library from Adafruit (Youtube link, embedded below).

The library is available on Github, and is compatible with SAMD21 and SAMD51 boards, as well as Nordic’s NRF52840. It allows the Arduino board to appear as a USB drive, and files can simply be dragged and dropped into place. The library can set up to use SPI flash, SD cards, or even internal chip memory as the storage medium.

Potential applications include images, audio files, fonts, or even configuration files. Future plans include porting the TinyUSB library to the ESP32-S2 as well. Being able to drag a settings file straight on to a board could make getting WiFi boards online much less of a hassle.

We’ve seen other nifty USB libraries before, VUSB is a great option if you need USB on your AVR microcontroller. Video after the break.

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Tiny Two-Digit Thermometer Has Long Battery Life

Like most of his work, this tiny two-digit thermometer shows that [David Johnson-Davies] has a knack for projects that make efficient use of hardware. No pin is left unused between the DS18B20 temperature sensor, the surface mount seven-segment LED displays, and the ATtiny84 driving it all. With the temperature flashing every 24 seconds and the unit spending the rest of the time in a deep sleep, a good CR2032 coin cell should power the device for nearly a year. The board itself measures only about an inch square.

You may think that a display that flashes only once every 24 seconds might be difficult to actually read in practice, and you’d be right. [David] found that it was indeed impractical to watch the display, waiting an unknown amount of time to read some briefly-flashed surprise numbers. To solve this problem, the decimal points flash shortly before the temperature appears. This countdown alerts the viewer to an incoming display, at the cost of a virtually negligible increase to the current consumption.

[David]’s project write-up explains how everything functions. He also steps through the different parts of the source code to explain how everything works, including the low power mode. The GitHub repository holds all the source files, and the board can also be ordered direct from OSH Park via their handy shared projects feature.

Low power consumption adds complexity to projects, but the payoffs can easily be worth the time spent implementing them. We covered a detailed look into low power WiFi microcontrollers that is still relevant, and projects like this weather station demonstrate practical low power design work.

Turbo Subaru Gets DIY Gauges

For the average motorist, the speedometer and the fuel indicator are the primary gauges of interest. Owners of performance or modified cars tend to like having more information on the way the car is running. [JustinN1] is firmly in that camp, and built some WiFi-enabled gauges for his Subaru WRX STi.

The gauges run on the ESP32 platform, chosen for its WiFi hardware and its ease of use with the Arduino platform. This makes programming a snap, and interfacing to a smartphone easy. OLED displays were chosen for their good visibility in both day and night conditions, which is important for automotive applications.

[JustinN1] developed both a boost/vacuum gauge and an oil pressure gauge, both useful for keeping an eye on what the engine is doing. Measuring boost is as simple as using an off-the-shelf analog air pressure sensor. The oil pressure sensor is a resistive part, and must is hooked up through a resistor divider to create an analog voltage for the ESP32 to read.

Code is on Github, and there’s even a version that displays a grinning face when you get into higher boost levels. There are also a series of housings to suit various mounting choices, to help give the gauges a more finished look. We’ve seen other gauge builds too, like this gear indicator for a Suzuki motorcycle. Video after the break.

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A Stylish Solution For Bike Navigation

[André Biagioni] is developing an open hardware bicycle navigation device called Aurora that’s so gorgeous it just might be enough to get you pedaling your way to work. This slick frame-mounted device relays information to the user through a circular array of SK6812 RGB LEDs, allowing you to find out what you need to know with just a quick glance down. No screen to squint at or buttons to press.

The hardware has already gone through several revisions, which is exactly what we’d expect to see for an entry into the 2019 Hackaday Prize. The proof of concept that [André] zip-tied to the front of his bike might have worked, but it wasn’t exactly the epitome of industrial design. It was enough to let him see that the idea had merit, and from there he’s been working on miniaturizing the design.

So how does it work? The nRF52832-powered Aurora connects to your phone over Bluetooth, and relays turn-by-turn navigation information to you via the circular LED array. This prevents you from having to fumble with your phone, which [André] hopes will improve safety. When you’re not heading anywhere specific, Aurora can also function as a futuristic magnetic compass.

With what appears to be at least three revisions of the Aurora hardware already completed by the time [André] put the project up on, we’re very interested in seeing where it goes from here. The theme for this year’s Hackaday Prize is moving past the one-off prototype stage and designing something that’s suitable for production, and so far we’d say the Aurora project is definitely rising to the challenge.

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Atomic Power Gets Small

There was a time when nuclear power plants were going to save the world. Barring accidents, the plants are clean and generate a lot of power. However, a few high-profile accidents and increased public awareness of some key issues have made nuclear power a hard sell, at least in the United States. The fastest growing nuclear power-related business in the US — according to sources — is companies decommissioning nuclear power plants. However, there’s a move afoot to make nuclear power a viable solution again. The company behind it says their plants will be cheaper to build, cheaper to operate, and are much safer than conventional plants. Are those claims reasonable?

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Gaze Upon This Intricate Victorian-Era Time Lock

The concept of a time lock is an old one, and here you can see an example of the clockwork and gears version that kept vaults sealed against unauthorized openings. Even if the correct combination was known, these devices prevented opening until a pre-arranged amount of time had passed. The fine folks at [Industrial Alchemy] got a copy of a Yale Triple L mechanical time lock, and like other devices of its kind it required manual winding to function. Since the device as a whole was sealed against tampering, winding and setting was done with a key via the small holes in the front.

These devices were mounted on the inside of a vault door, and worked by mechanically interfacing with the lock mechanism in a variety of different ways depending on make and model. While the time lock was engaged, opening the door was prevented even if the correct combination was used. You may notice the multiple movements; this was for redundancy. The movements were interfaced in a mechanical OR arrangement, meaning that the first one to count down to zero would disengage the time lock. In the case of a malfunction, the backup movements would be responsible for preventing a total lockout — a condition as inconvenient and embarrassing as it would be costly.

Embedded below is a video that focuses on swapping movements in a time lock, but happens to also do a good job of showing off the mechanical design and components. Clockwork was the high technology of its time, and interest in it has seen something of a resurgence now that 3D printing is commonplace.

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