Author: Bryan Cockfield

1759 Articles

Smart Doorbell Focuses On Privacy

August 18, 2023 by 11 Comments

As handy as having a smart doorbell is, with its ability to remotely see who’s at the front door from anywhere with an Internet connection, the off-the-shelf units are not typically known for keeping user privacy as a top priority. Even if their cloud storage systems were perfectly secure (which is not a wise assumption to make) they have been known to give governmental agencies and police free reign to view the videos whenever they like. Unfortunately if you take privacy seriously, you might need to implement your own smart doorbell yourself.

The project uses an ESP32-CAM board as the doorbell’s core, paired with a momentary push button and all housed inside a 3D-printed enclosure. [Tristam] provides a step-by-step guide, including printing the enclosure, configuring the ESP32-CAM to work with the popular open-source home automation system ESPHome, handling doorbell notifications automatically, and wiring the components. There are plenty of other optional components that can be added to this system as well, including things like LED lighting for better nighttime imaging.

[Tristam] isn’t much of a fan of having his home automation connected to the Internet, so the device eschews wireless connections and batteries in favor of a ten-meter USB cable connected to it from a remote machine. As far as privacy goes, this is probably the best of all worlds as long as your home network isn’t doing anything crazy like exposing ports to the broader Internet. It also doesn’t need to be set up to continuously stream video either; this implementation only takes a snapshot when the doorbell button is actually pressed. Of course, with a few upgrades to the ESP circuitry it is certainly possible to use these chips to capture video if you prefer.

Thanks to [JohnU] for the tip!

Polaroid Develops Its Pictures Remotely

August 16, 2023 by 8 Comments

For those who didn’t experience it, it’s difficult to overstate the cultural impact of the Polaroid camera. In an era where instant gratification is ubiquitous, it’s easy to forget that there was a time when capturing a photograph meant waiting for film to be developed or relying on the meticulous art of darkroom processing. Before the era of digital photography, there was nothing as close to instant as the Polaroid. [Max] is attempting to re-capture that feeling with a modified Polaroid which instantly develops its pictures in a remote picture frame.

The build is based on a real, albeit non-functional, Polaroid Land Camera. Instead of restoring it, a Raspberry Pi with a camera module is placed inside the camera body and set up to capture pictures. The camera needs to connect to a Wi-Fi network before it can send its pictures out, though, and it does this automatically when taking a picture of a QR code. When a picture is snapped, it sends it out over the Internet to wherever the picture frame is located, which has another Raspberry Pi inside connected to an e-ink screen. Once a picture is taken on the camera it immediately shows up in the picture frame.

To help preserve the spirit of the original Polaroid, at no point is an image saved permanently. Once it is sent to the frame, it is deleted from the camera, and the next picture taken overwrites the last. And, for those who are only familiar with grayscale e-ink displays as the integral parts of e-readers, there have been limited options for color displays for a while now, as we saw in this similar build which was painstakingly built into a normal-looking picture frame as part of an attempted family prank.

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Automation For The NES

August 15, 2023 by 11 Comments

Old hardware might not be anywhere close to as powerful as modern technology, but it does have a few perks. Aesthetics can of course drive the popularity of things like retro gaming systems, but the ease of understanding the underpinnings of their inner workings is also critical. The Nintendo Entertainment System, now nearly four decades old, is a relatively simple machine by modern standards and this lends the system to plenty of modifications, like this controller that allows the system to be somewhat automated.

The original NES controller used a fairly simple shift register to send button presses to the system. The system outputted a latch signal to the controller, the shift register would take as input the current state of the buttons, and then would send them one-by-one to the system at a rate of around 1000 times per second. These signals can be sent without a controller easily enough, too. This build uses a CD4021 shift register, which is the same as the original controller, but instead of reading button states it accepts its inputs from a separate computer via a latching circuit. In this case, the separate computer is a custom design that came about through adapting cassette storage for a 6502-based computer, but it could come from anything else just as easily.

With this system in place, it’s possible to automate gameplay to some extent. Since the system can’t get feedback about the game in its current state, it requires some precise timing to get it to play the game well, and a lot of tuning needs to go into it. This isn’t just a one-off, either. Similar methods are how we get tool-assisted speedruns of games and although these are often done in emulators instead of on real hardware, they can result in some interesting exploits.

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Making Things Square In Three Dimensions

August 13, 2023 by 32 Comments

Measure twice, cut once is excellent advice when building anything, from carpentry to metalworking. While this adage will certainly save a lot of headache, mistakes, and wasted material, it will only get you part of the way to constructing something that is true and square, whether that’s building a shelf, a piece of furniture, or an entire house. [PliskinAJ] demonstrates a few techniques to making things like this as square as possible, in all three dimensions.

The first method for squaring a workpiece is one most of us are familiar with, which is measuring the diagonals. This can be done with measuring tape or string and ensures that if the diagonals are equal lengths, the workpiece is square. That only gets it situated in two dimensions, though. To ensure it’s not saddle-shaped or twisted, a little more effort is required. [PliskinAJ] is focused more on welding so his solutions involve making sure the welding tables are perfectly flat and level. For larger workpieces it’s also not good enough to assume the floor is flat, either, and the solution here is to minimize the amount of contact it has with the surface by using something like jack stands or other adjustable supports.

There are a few other tips in this guide, including the use of strategic tack welds to act as pivot points and, of course, selecting good stock to build from in the first place, whether that’s lumber or metal. Good design is a factor as well. We’ve also featured a few other articles on accuracy and precision,

Liquid Metal Battery Goes Into Production

August 12, 2023 by 89 Comments

The news is rife with claims of the next great thing in clean energy generation, but most of these technologies never make it to production. Whether that’s due to cost issues, production, or scalability, we’re often teased with industry breakthroughs that never come to fruition. Multi-layered solar panels, wave and tidal energy, and hydrogen fuel cells are all things that are real but can’t seem to break through and overtake other lower cost, simpler, and proven technologies. One that seems to be bucking this trend is the liquid metal battery, which startup Ambri is putting into service on the electrical grid next year.

With lithium ion battery installations running around $405 per kilowatt-hour, Ambri’s battery technology is already poised to be somewhat disruptive at a cost of about half that. The construction method is simpler than lithium as well, using molten metal electrodes and a molten salt electrolyte. Not only is this more durable, it’s also not flammable and is largely immune to degradation over time. The company’s testing results indicate that after 20 years the battery is expected to still retain 95% of its capacity. The only hitch in scaling this technology could be issues with sourcing antimony, one of the metals needed for this type of construction.

Even though Ambri can produce these batteries for $180 to $250 per kilowatt-hour, they need to get the costs down to about $20 for the technology to be cost-competitive with “base load” power plants (an outdated term in itself). They do project their costs to come down significantly and hit this mark by 2030, which would put electrical grids on course to be powered entirely by renewables. Liquid metal batteries aren’t the only nontraditional battery out there trying to solve this problem, though. Another promising interesting energy storage technology on the horizon is phase-change materials.

Solar Boat Makes Waves

August 11, 2023 by 11 Comments

The two best days in a boat owner’s life are the day they buy it, and the day they sell it. At least, that’s the common saying among people who actually spend money to buy a boat. [saveitforparts], on the other hand, looks like he’s going to have many more great days on this boat than that since he cobbled it together nearly for free, and he won’t even need to purchase any fuel for it since it runs on solar power.

The build starts with [saveitforparts] heading out to a literal pile of boats in his yard, unearthing an old single-person sailboat, and then fixing the major problems with its hull. With a new coat of red paint, the focus turns to the drivetrain. Propulsion is handled by an electric trolling motor found at an auction for $8 and is powered by an off-the-shelf battery bank provided by a sponsor of his channel. A pair of solar panels (which were traded for) fitted to outriggers keep the battery bank topped off, and there’s plenty of energy left over with this setup to charge drone batteries and other electronics while out on the lake.

[saveitforparts] reports that the single-passenger solar boat is remarkably stable on the water and fairly quick at full speed thanks to its light weight. He even hypothesizes that it could be fished from. The only thing not particularly stable was towing it to the lake, as the rough roads and permanently-attached solar panel outriggers weren’t particularly congruent with each other. If you’re looking for something similar to carry a few passengers, though, have a look at this much larger version.

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Weather Station With Distributed Sensors

August 11, 2023 by 2 Comments

Building a weather station is a fairly common project that plenty of us have taken on, and for good reason. They can be built around virtually any microcontroller or full-scale computer, can have as many or few sensors as needed, and range from simple, straightforward projects to more complex systems capable of doing things like sending data off to weather services like Weather Underground. This weather station features a few innovations we don’t often see, though, with a modular and wireless design that makes it versatile and easy to scale up or down as needed.

Each of the modules in this build use the ESP32 platform, which simplifies design and also takes care of the wireless capability needed. The base station gets a few extra sensors including those for carbon dioxide, volatile organic compounds, and nitrogen oxides. It also includes a screen which can be used to display a wide variety of data gathered locally but also includes forecast information fetched from the free OpenWeatherMap API. For the sensor modules, BME280 sensors are used for temperature, pressure, and humidity and each module includes its own solar panel and battery with the ESP32 chips set to operate using as little energy as possible.

One of the things that helps easily integrate all of the sensor modules is the use of ESP-NOW, which we have seen a few times before. It essentially eliminates the need for a router and allows ESP modules to connect directly with one another. The build also goes into detail about most of the aspects of this project including the programming of the GUI that the ESP32 base station displays on its screen, so for anyone looking to start their own weather station project this should be an excellent guide. Make sure to check out this one as well if you want to send all of your weather data to Weather Underground.