Hack Your Engine Virtually

August 11, 2022 by Al Williams 21 Comments

It is no secret that we like simulating circuits before we build something and there are plenty of great tools for that. But what about those of us who work on cars? Well, you might try engine-sim which is a real-time internal combustion engine simulation. Honestly, the program freely admits that it isn’t accurate enough to do engineering or engine tuning. But on the plus side, it has audio output and is at least good as an educational tool to show an engine running and how different parameters might affect it. You can see a video of the tool below.

[Ange-Yaghi] mentions that the code was primarily to power the YoutTube demo. However, the Readme hints that it might be better — or at least different — and collaboration to make it better is welcome.

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Back Up Encrypted ZFS Data Without Decrypting It, Even If TrueNAS Doesn’t Approve

August 11, 2022 by Donald Papp 9 Comments

[Michael Lynch] recently replaced his Synology NAS with a self-built solution built on ZFS, a filesystem with a neat feature: the ability to back up encrypted data without having to decrypt it first. The only glitch is that [Michael] is using TrueNAS, and TrueNAS only wants to back up unencrypted ZFS data to another TrueNAS system. Fortunately, there’s a way around this that isn’t particularly complicated, but definitely requires leveraging the right tools. It also provides an educational walkthrough for how ZFS handles these things.

The solution is a small handful of shell scripts to manage full and incremental backups and restores of encrypted datasets, without having to decrypt the data first. As mentioned, this is something TrueNAS will handle by default, but only if the destination is also a TrueNAS system. Now, [Michael] can send that backup to off-site cloud storage with only a little extra work.

There’s one additional trick [Michael] uses to monitor his backups. He leverages a paid (but with a free tier) service called Cronitor. It’s not very obvious from the site’s features, but there is a way to implement cron job monitoring that doesn’t require adding any software whatsoever. Here’s how that part works: Cronitor provides a custom, unique URL. If that URL isn’t visited regularly (for example, because the cron job fails), then the user is notified. By integrating this into an existing cron job, one can be notified. Such an integration would look like this:

0 0 3 * * monthly-job && curl --silent https://cronitor.link/p/<API-KEY>/monthly-job?state=complete

In short, if the cron job runs successfully, curl checks in by visiting the custom URL. If that doesn’t happen, the user gets a notification. No added software, just a simple leveraging of a free service for some added peace of mind.

Backups are easy to neglect, so maybe it’s time to take a few moments to consider what you do for data storage, including how you’d recover from disaster.

Presence-Detecting Cushion Keeps You From Sitting Your Life Away

August 11, 2022 by Dan Maloney 13 Comments

They say that sitting is the new smoking. They’re wrong — smoking is much, much worse, for you than sitting, and smoking only while standing or while jogging around the block in no way to justify the habit. But they’re also not wrong that humans weren’t made for extended periods parked on their posteriors, but we do it anyway, to the detriment of our heart health, posture, and general well-being. So something like this butt-detecting stand-up reminder could make a big difference to your health.

While like many of us, [Dave Bennett] has a wearable that prompts him to get up and move around after detecting 30 minutes of sitting, he found that it’s too easy to dismiss the alarm and just go right on sitting. Feeling like he needed a little more encouragement to get up and go, he built a presence detector completely from scratch. His sensor is a sheet of static-protective Velostat foam wrapped in conductive tape; when compressed, the resistance across the pad drops, making it easy to detect with a simple comparator circuit.

We admit to getting excited when we first saw the alarm circuit; a quick glance at the schematic seemed like it was based on a 555, which it totally could be. But no, [Dave]’s design goals include protection against spoofing the alarm with a quick “cheek sneak,” which was most easily implemented in code. So that 8-pin device in the circuit is an ATtiny85, which sounds the alarm after 30 minutes and requires him to stay off his butt for a full minute before resetting. The video below hits the high points of design and shows it in use.

Annoying? Yes, but that’s the point. Of course a standing desk would do the same thing, but that’s not going to work for everyone, so this is a nice alternative.

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Want To Use A Classic Mac Mouse On A Modern Computer? No? Here’s How To Do It Anyway

August 11, 2022 by Donald Papp 23 Comments

Need to hook a classic Mac mouse up to your modern machine with the help of a DIY USB adapter? [John Floren] has you covered. [John]’s solution uses a board with an ATmega32U4 microcontroller on it to connect to the Mac mouse on one end, and emulate a USB HID (Human Interface Device) on the other. A modern machine therefore recognizes it like it would any other USB input device.

Why is this necessary? The connector on the classic Mac mouse may look like a familiar DE-9 connector, but it is not an RS-232 device and wouldn’t work if it were plugged into a 9-pin serial port. The classic Mac mouse uses a different pinout, and doesn’t have much for brains on the inside. It relies on the host computer to read its encoders and button states directly.

This project is actually a bit of an update to a piece of earlier work [John] did in making a vintage Depraz mouse work with modern systems. He suspected that it wouldn’t take much to have it also work with a classic Mac mouse, and he was right — all it took was updating the pin connections and adding some pull-up resistors. The source code and design files are on GitHub.

Even if one does not particularly want to use a classic Mac mouse for daily work, there’s definitely value in this kind of thing for those who deal in vintage hardware: it allows one to function-check old peripherals without having to fire up a vintage machine.

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Haptic Baby Monitor Gets The Wearer’s Attention

August 11, 2022 by Tom Nardi 10 Comments

Anyone who’s ever slept through a morning’s alarm can tell you that sounds, even loud piercing ones, don’t always wake a person out of a deep sleep. Similarly, hearing a baby cry on the other side of the monitor might not always wake a parent up in the middle of the night. So what’s the solution? This haptic baby monitor created by [Guy Dupont] certainly looks like it has some promise.

[Guy] picked up a fairly standard baby monitor from VTech and popped it open to see how he could tie a vibration motor into the original circuitry. He originally thought he’d have to do some signal processing magic to figure out the amplitude of the audio, but then he realized that the five LEDs on the front of the unit that light up to indicate the audio level were already doing the hard work for him.

Detecting audio level by reading the status of the LEDs.

So he wired each of the LEDs up to the pins of a Seeed Studio XIAO nRF52840 microcontroller, and wrote some code that would poll their status a few hundred times per second. Dividing the total number of LEDs by the count of how many are currently illuminated gives him a nice average that he can use to set the intensity of the vibration motor that he’s built into a stretchy armband.

For extra points, [Guy] is also using the Bluetooth capability of the XIAO to provide a rudimentary configuration service — just connect up to the MCU with a Bluetooth serial application on your computer or phone, and fire off a value between 0 and 10 to augment the motor’s intensity. There’s also a BLE characteristic which can be read from a client device to determine the currently detected audio amplitude, which could be used to chart how well the baby is sleeping over time. Alternately, as demonstrated at the end of the video, you could use it to play Flappy Bird.

It’s an elegant modification that could potentially hold promise for parent’s who need a bit of extra help keeping tabs on their miniature humans. This isn’t the first time we’ve seen hackers try to improve upon the classic baby monitor, but this is arguably the most approachable attempt we’ve seen to date.

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Microsoft’s New Simulator Helps Train Drone AIs

August 11, 2022 by Lewin Day 15 Comments

Testing any kind of project in the real world is expensive. You have to haul people and equipment around, which costs money, and if you break anything, you have to pay for that too! Simulation tends to come first. Making mistakes in a simulation is much cheaper, and the lessons learned can later be verified in the real world. If you want to learn to fly a quadcopter, the best thing to do is get some time behind the sticks of a simulator before you even purchase anything with physical whirly blades.

Oddly enough, the same goes for AI. Microsoft built a simulation product to aid the development of artificial intelligence systems for drones by the name of Project AirSim. It aims to provide a comprehensive environment for the testing of drone AI systems, making development faster, cheaper, and more practical.

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Building The Most High-Tech Pond In The Neighborhood

August 11, 2022 by Tom Nardi 14 Comments

What do you think of when you hear the word pond? If you’re like most people, it conjures up images of a simple water-filled hole in the ground, maybe with a few fish added in for good measure. But not [Anders Johansson] — his pond is a technical marvel, utilizing more unique pieces of hardware and software than many of the more traditional projects that have graced these projects over the years.

In fact, this is one of those projects that is so grand in scope that any summary we publish here simply can’t do it justice. The aptly-named Poseidon project is built up of several modular components, ranging from an automated fish feeder to an array of sensors to monitor the condition of the water itself. How many other ponds can publish their current water level, pH, and oxygen saturation over MQTT?

The ESP8266 fish feeder is just one element of Poseidon

[Anders] has provided schematics, 3D models, and source code for all the various systems built into the pond, but the documentation is where this project really shines. Each module has it’s own detailed write-up, which should provide you with more than enough guidance should you want to recreate or remix what he’s put together. Even if you use only one or two of the modules he’s put together, you’ll still be ahead of the game compared to the chumps who have to maintain their pond the old fashioned way.

In the past we’ve seen projects that tackled some of the individual elements [Anders] has developed, such as 3D printed fish feeders, but after searching through the archives we can’t find anything that’s even half as ambitious as Poseidon. At least, not for ponds. It reminds us more of a highly advanced aquaponics setup, and we wonder if that might not be a possible spin-off of the core project in the future.