Stamp breakout boards.

Stamp: Modular Breakout Boards For SMD Prototyping

[Kalesh Sasidharan] from Sciotronics wrote in to tell us about their project, Stamp: a modular set of template breakout boards designed to make prototyping with SMD components faster, easier, and more affordable. No breadboards, custom PCBs, or tangled jumper wires required. The project has blasted past its Kickstarter goal, and is on track to start shipping in September.

Stamp was created out of frustration with the traditional SMD prototyping workflow. Breadboards don’t support SMD parts directly, and using adapters quickly gets messy, especially when you need to iterate or modify a design. Ordering PCBs for every small revision just adds delay, and cost.

Stamp solves this by offering reusable template boards with commonly used SMD footprints. You place the main component on the front and the supporting components on the back. Many complete circuits, such as buck converters, sensor blocks, microcontrollers, and so on, can fit on a single 17.8 × 17.8 mm board.

Most Stamps feature custom castellated holes, designed for side-by-side or right-angle edge connections, enabling a modular, reconfigurable approach to circuit building. The plan is to make the designs fully open source, so that others can build or adapt them. Although many PCB manufacturers might not have the facilities to make the special castellated edges which are available on some Stamps.

Dave Jones from the EEVblog covered the Stamp on one of his recent Mailbag videos, which you can check out below. This isn’t the first time we’ve seen somebody promise to reinvent the breadboard, but we do appreciate the simplicity of this approach.

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Various hardware components laid out on a workbench.

Working On Open-Source High-Speed Ethernet Switch

Our hacker [Andrew Zonenberg] reports in on his open-source high-speed Ethernet switch. He hasn’t finished yet, but progress has been made.

If you were wondering what might be involved in a high-speed Ethernet switch implementation look no further. He’s been working on this project, on and off, since 2012. His design now includes a dizzying array of parts. [Andrew] managed to snag some XCKU5P FPGAs for cheap, paying two cents in the dollar, and having access to this fairly high-powered hardware affected the project’s direction.

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A white control box is shown in the foreground. The box has an LCD display, eight button, and two barbed fittings for flexible tubing.

Using Pitot Tubes For More Than Aircraft

When we hear the words “pitot tube,” we tend to think more of airplanes than of air ducts, but [Franci Kopač]’s guide to pitot tubes for makers shows that they can be a remarkably versatile tool for measuring air speed, even in domestic settings.

A pitot tube is a tube which faces into an air flow, with one hole at the front of the tube, and one on the side. It’s then possible to determine the air speed by measuring the pressure difference between the side opening and the end facing into the wind. At speeds, temperatures, and altitudes that a hacker’s likely to encounter (i.e. not on an airplane), the pressure difference is pretty small, and it’s only since the advent of MEMS pressure sensors that pitot tubes became practical for amateurs.

[Franci]’s design is based on a Sensiron SDP differential pressure sensor, a 3D-printed pitot tube structure, some tubing, and the microcontroller of your choice. It’s important to position the tube well, so that it doesn’t experience airflow disturbances from other structures and faces straight into the air flow. Besides good positioning, the airspeed calculation requires you to know the air temperature and absolute pressure.

[Franci] also describes a more exotic averaging pitot tube, a fairly simple variation which measures air speed in cavities more accurately. He notes that this provides a more inexpensive way of measuring air flow in ducts than air conditioning flow sensors, while being more resilient than propeller-based solutions – he himself used pitot tubes to balance air flow in his home’s ventilation. All of the necessary CAD files and Arduino code are available on his GitHub repository.

If you’re looking for a more conventional duct flow meter, we’ve covered one before. We’ve even seen a teardown of a pitot tube sensor system from a military drone.

Two rings of magnets are shown encasing a circular channel in a white plastic piece. The channel is filled with liquid metal, and a loop of wire is about to be lowered into the metal.

Magnetohydrodynamic Motors To Spin Satellites

Almost all satellites have some kind of thrusters aboard, but they tend to use them as little as possible to conserve chemical fuel. Reaction wheels are one way to make orientation adjustments without running the thrusters, and [Zachary Tong]’s liquid metal reaction wheel greatly simplifies the conventional design.

Reaction wheels are basically flywheels. When a spacecraft spins one, conservation of angular momentum means that the wheel applies an equal and opposite torque to the spacecraft, letting the spacecraft orient itself. The liquid-metal reaction wheel uses this same principle, but uses a loop of liquid metal instead of a wheel, and uses a magnetohydrodynamic drive to propel the metal around the loop.

[Zach] built two reaction wheels using Galinstan as their liquid metal, which avoided the toxicity of a more obvious liquid metal. Unfortunately, the oxide skin that Galinstan forms did make it harder to visualize the metal’s motion. He managed to get some good video, but a clearer test was their ability to produce torque. Both iterations produced a noticeable response when hung from a string and activated, and achieved somewhat better results when mounted on a 3D-printed air bearing.

Currently, efficiency is the main limitation of [Zach]’s motors: he estimates that the second model produced 6.2 milli-newton meters of torque, but at the cost of drawing 22 watts. The liquid metal is highly conductive, so the magnetohydrodynamic drive takes high current at low voltage, which is inconvenient for a spacecraft to supply. Nevertheless, considering how hard it is to create reliable, long-lasting reaction wheels the conventional way, the greatly improved resilience of liquid-metal reaction wheels might eventually be worthwhile.

If you’re curious for a deeper look at magnetohydrodynamic drives, we’ve covered them before. We’ve also seen [Zach]’s earlier experiments with Galinstan.

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This Extra-Large, Two-Stage Fume Extractor Really Sucks

Solder fumes are not nice on the lungs; nor are fumes from superglue, epoxy, or a whole mess of other things we often find ourselves using on the bench. Some people might be able to go the fume hood route to toss that all outside, but for the rest of us, there’s fume extractors. [Raph] has produced an extra-large, carbon-filtering, two-stage fume extractor that by all accounts really sucks — it is effective at hoovering up solder fumes up to 10″ from its inlet.

Photo of fume extractor
Note the 18V tool battery in the base. That’ll go for a bit.

Even better, [Raph] built a battery box for an 18 V cordless tool battery, and broke out banana plugs so this doubles as a variable power supply via a cheap LM2596 based DC-DC converter. It also serves as a speed controller for the fans, which makes us wonder if you can adjust the PSU output and the fan speed independently…

Maximum suckage is achieved through careful baffle design. Check out the blog to see the trial-and-error process at work. Of course, having a 200 mm axial fan and 140 mm blower fan front and rear is going to move some air no matter what. Which is required to get air flow through the 38 mm thick activated carbon filter that should scrub all nasties quite nicely. We aren’t filtration experts but we can agree with [Raph]’s estimate that it will last “a while”.

If you want to roll your own, all of the STEP files are on GitHub, and [Raph]’s blog has an excellent step-by-step build guide. We’ve seen other hacks from [Raph] before, from his dovetailed modular breadboard to the machine that shaped his bed and automation for his camper van.

A high level pictorial schematic of the basement monitor.

Making Sure The Basement Stays Dry With An ESP8266

The hack we have for you today is among our most favorite types of hack: a good, honest, simple, and well documented implementation that meets a real need. Our hacker [Solo Pilot] has sent in a link to their basement monitor.

The documentation is quite good. It’s terse but comprehensive with links to related information. It covers the background, requirements, hardware design, sensors, email and SMS alerts, software details, and even has some credits at the end.

Implementing this project would be a good activity for someone who has already made an LED flash and wants to take their skills to the next level by sourcing and assembling the hardware and then configuring, compiling, deploying, and testing the software for this real-world project.

To make this project work you will need to know your way around the Arduino IDE in order to build the software from the src.zip file included with the documentation (hint: extract the files from src.zip into a directory called AHT20_BMP280 before opening AHT20_BMP280.ino and make sure you add necessary boards and libraries).

One feature of the basement monitor that we would like to see is a periodic “everything’s okay” signal from the device, just so we can confirm that the reason we’re not getting an alarm about flooding in the basement is because there is no flood, and not because the battery ran dead or the WiFi went offline.

If you’ve recently started on your journey into where electronics meets software a project such as this one is a really great place to go next. And of course once you are proficient with the ESP8266 there are a thousand such projects here at Hackaday that you can cut your teeth on. Such as this clock and this fault injection device.

New Bismuth Transistor Runs 40% Faster And Uses 10% Less Power

Recently in material science news from China we hear that [Hailin Peng] and his team at Peking University just made the world’s fastest transistor and it’s not made of silicon. Before we tell you about this transistor made from bismuth here’s a whirlwind tour of the history of the transistor.

The Bipolar Junction Transistor (BJT, such as NPN and PNP) was developed soon after the point-contact transistor which was developed at Bell Labs in 1947. Then after Resistor-Transistor Logic (RTL) came Transistor-Transistor Logic (TTL) made with BJTs. The problem with TTL was too much power consumption.

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