sensor

243 Articles

DIY Repair Brings An X-Ray Microscope Back Into Focus

September 22, 2023 by 6 Comments

Aside from idle curiosity, very few of us need to see inside chips and components to diagnose a circuit. But reverse engineering is another story; being able to see what lies beneath the inscrutable epoxy blobs that protect the silicon within is a vital capability, one that might justify the expense involved in procuring an X-ray imager.  But what’s to be done when such an exotic and expensive — not to mention potentially deadly — machine breaks down? Obviously, you fix it yourself!

To be fair, [Shahriar]’s Faxitron MX-20 digital X-ray microscope was only a little wonky. It still generally worked, but just took a while to snap into the kind of sharp focus that he needs to really delve into the guts of a chip. This one problem was more than enough to justify tearing into the machine, but not without first reviewing the essentials of X-ray production — a subject that we’ve given a detailed look, too — to better understand the potential hazards of a DIY repair.

With that out of the way and with the machine completely powered down, [Shahriar] got down to the repair. The engineering of the instrument is pretty impressive, as it should be for something dealing with high voltage, heavy thermal loads, and ionizing radiation. The power supply board was an obvious place to start, since electrostatically focusing an X-ray beam depends on controlling the high voltage on the cathode cup. After confirming the high-voltage module was still working, [Shahriar] homed in on a potential culprit — a DIP reed relay.

Replacing that did the trick, enough so that he was able to image the bad component with the X-ray imager. The images are amazing; you can clearly see the dual magnetic reed switches, and the focus is so sharp you can make out the wire of the coil. There are a couple of other X-ray treats, so make sure you check them out in the video below.

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Hackaday Links: September 10, 2023

September 10, 2023 by 17 Comments

Most of us probably have a vision of how “The Robots” will eventually rise up and deal humanity out of the game. We’ve all seen that movie, of course, and know exactly what will happen when SkyNet becomes self-aware. But for those of you thinking we’ll get off relatively easy with a quick nuclear armageddon, we’re sorry to bear the news that AI seems to have other plans for us, at least if this report of dodgy AI-generated mushroom foraging manuals is any indication. It seems that Amazon is filled with publications these days that do a pretty good job of looking like they’re written by human subject matter experts, but are actually written by ChatGPT or similar tools. That may not be such a big deal when the subject matter concerns stamp collecting or needlepoint, but when it concerns differentiating edible fungi from toxic ones, that’s a different matter. The classic example is the Death Cap mushroom (Amanita phalloides) which varies quite a bit in identifying characteristics like color and size, enough so that it’s often tough for expert mycologists to tell it apart from its edible cousins. Trouble is, when half a Death Cap contains enough toxin to kill an adult human, the margin for error is much narrower than what AI is likely to include in a foraging manual. So maybe that’s AI’s grand plan for humanity — just give us all really bad advice and let Darwin take care of the rest.

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Clock Runs Computer In Slow-Motion

July 8, 2023 by 27 Comments

At the heart of all computers is a clock, a dedicated timepiece ensuring that all of the parts of the computer are synchronized and can work together to execute the instructions that the computer receives. Clock speeds for most modern off-the-shelf computers and smartphones operate around a billion cycles per second, and even clocks that tick at a human-dizzying speed of a million times per second have been around since at least the 1970s. But there’s no reason a computer can’t run at a much slower speed, as [Greg] demonstrates in this video where he slows down a 6502 processor to a single clock cycle per second.

To reduce the clock speed from the megahertz range down to a single hertz or single clock cycle per second, [Greg] is using the pendulum from an actual clock. He attaches a small magnet to the bottom of the pendulum which is counted by a sensor as it swings past. Feeding that pulse into a monostable conditioner yields a clock signal which is usable for one of his 6502-based computers, and at this extremely slow rate, it’s possible to see the operation of a lot of the computers’ inner workings a step at a time. In fact, he optimized the computer’s operation as this slow speed let him see some inefficiencies in the program he was running.

It helps if your processor is static, of course. Older CPUs with dynamic storage for registers and some with limited-range PLLs would not work with this technique. The 8080A, for example, required a clock of at least 500 kHz.

Not only can this computer use a pendulum clock as the basis for its internal clock, but [Greg] also rigged up a mechanism to use a heartbeat. Getting in a little bit of exercise to increase his heart rate first will noticeably increase the computer’s speed. And, if you’re looking to get a deeper glimpse into the inner workings of a computer, we’d recommend looking at one which forgoes transistors in favor of relays.

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Feeling The Heat: Railway Defect Detection

March 28, 2023 by 29 Comments

On the technology spectrum, railroads would certainly seem to skew toward the brutally simplistic side of things. A couple of strips of steel, some wooden ties and gravel ballast to keep everything in place, some rolling stock with flanged wheels on fixed axles, and you’ve got the basics that have been moving freight and passengers since at least the 18th century.

But that basic simplicity belies the true complexity of a railway, where even just keep keeping the trains on the track can be a daunting task. The forces that a fully loaded train can exert on not only the tracks but on itself are hard to get your head around, and the potential for disaster is often only a failed component away. This became painfully evident with the recent Norfolk Southern derailment in East Palestine, Ohio, which resulted in a hazardous materials incident the likes of which no community is ready to deal with.

Given the forces involved, keeping trains on the straight and narrow is no mean feat, and railway designers have come up with a web of sensors and systems to help them with the task of keeping an eye on what’s going on with the rolling stock of a train. Let’s take a look at some of the interesting engineering behind these wayside defect detectors.

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Smart Occupancy Sensor Knows All

March 23, 2023 by 32 Comments

In the last few decades, building engineers and architects have made tremendous strides in improving the efficiency of various buildings and the devices that keep them safe and comfortable to live in. The addition of new technology like heat pumps is a major factor, as well as improvements on existing things like insulation methods and building materials. But after the low-hanging fruit is picked, technology like this smart occupancy sensor created by [Sina Moshksar] might be necessary to help drive further efficiency gains.

Known as RoomSense IQ, the small device mounts somewhere within a small room and uses a number of different technologies to keep track of the number of occupants in a room. The primary method is mmWave radar which can sense the presence of a person up to five meters away, but it also includes a PIR sensor to help prevent false positives and distinguish human activity from non-human activity. The device integrates with home automation systems to feed them occupancy data to use to further improve the performance of those types of systems. It’s also designed to be low-cost and easy to install, so it should be relatively straightforward to add a few to any existing system as well.

The project is also documented on this GitHub page, for anyone looking to build a little more data into their home automation system or even augment their home security systems. We imagine that devices like this could be used with great effect paired with a heating device like this, and we’ve also seen some other interesting methods of determining occupancy as well.

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Remote Water Quality Monitoring

March 20, 2023 by 8 Comments

While it can be straightforward to distill water to high purity, this is rarely the best method for producing water for useful purposes. Even drinking water typically needs certain minerals in it, plants may need a certain pH, and wastewater systems have a whole host of other qualities that need to be measured. Measuring water quality is a surprisingly complex endeavor as a result and often involves a wide array of sensors, much like this water quality meter from [RowlesGroupResearch].

The water quality meters that they are putting to use are typically set up in remote locations, without power, and are targeting natural bodies of water and also wastewater treatment plants. Temperature and pH are simple enough to measure and grasp, but this device also includes sensors for total dissolved solids (TDS) and turbidity which are both methods for measuring various amounts and types of particles suspended in the water. The build is based around an Arduino so that it is easy for others to replicate, and is housed in a waterproof box with a large battery, and includes data logging to an SD card in order to make it easy to deploy in remote, outdoor settings and to gather the data at a later time.

The build log for this device also goes into detail about all of the steps needed to set this up from scratch, as well as a comprehensive bill of materials. This could be useful in plenty of professional settings such as community wastewater treatment facilities but also in situations where it’s believed that industrial activity may be impacting a natural body of water. For a water quality meter more focused on drinking water, though, we’d recommend this build that is trained on its own neural network.

Low-Power Wi-Fi Includes E-Paper Display

March 10, 2023 by 6 Comments

Designing devices that can operate in remote environments on battery power is often challenging, especially if the devices need to last a long time between charges or battery swaps. Thankfully there are some things available that make these tasks a little easier, such as e-ink or e-paper displays which only use power when making changes to the display. That doesn’t solve all of the challenges of low-power devices, but [Albertas] shows us a few other tricks with this development board.

The platform is designed around an e-paper display and is meant to be used in places where something like sensor data needs to not only be collected, but also displayed. It also uses the ESP32C3 microcontroller as a platform which is well-known for its low power capabilities, and additionally has an on-board temperature and humidity sensor. With Bluetooth included as well, the tiny device can connect to plenty of wireless networks while consuming a remarkably low 34 µA in standby.

With a platform like this that can use extremely low power when not taking measurements, a battery charge can last a surprisingly long time. And, since it is based on common components, adding even a slightly larger battery would not be too difficult and could greatly extend this capability as well. But, we have seen similar builds running on nothing more than a coin cell, so doing so might only be necessary in the most extreme of situations.