Author: Bryan Cockfield

1721 Articles

Small Print Bed? No Problem!

January 24, 2025 by 7 Comments

One of the major limitations of 3D printers is the size of the printable area. The robotic arm holding the printer head can only print where it can reach, after all. Some methods of reducing this constraint have been tried before, largely focusing on either larger printers or printer heads that are mobile in some way. Another approach to increasing the size of prints beyond the confined space typical of most consumer-grade 3D printers is to create some sort of joinery into the prints themselves so that larger things can be created. [Cal Bryant] is developing this jigsaw-based method which has allowed him to produce some truly massive prints.

Rather than making the joints by hand, [Cal]’s software will cut up a model into a certain number of parts when given the volume constraints of a specific 3D printer so it can not only easily print the parts, but also automatically add the jigsaw-like dovetail joints to each of the sections of the print. There were a few things that needed prototyping to get exactly right like the tolerance between each of the “teeth” of the joint, which [Cal] settled on 0.2 mm which allows for a strong glued joint, and there are were some software artifacts to take care of as well like overhanging sections of teeth around the edges of prints. But with those edge cases taken care of he has some working automation software that can print arbitrarily large objects.

[Cal] has used this to build a few speaker enclosures, replacing older MDF designs with 3D printed ones. He’s also built a full-size arcade cabinet which he points out was an excellent way to use up leftover filament. Another clever way we’ve seen of producing prints larger than the 3D printer is to remove the print bed entirely. This robotic 3D printer can move itself to a location and then print directly on its environment.

Electric Vehicle Charging Heats Up

January 22, 2025 by 64 Comments

As the electric vehicle takeover slowly lumbers along, marginally increasing efficiencies for certain applications while entrenching car-centric urban design even further, there are some knock-on effects that are benefiting people and infrastructure beyond simple transportation. Vehicle-to-grid technology has applications for providing energy from the car back to the grid for things like power outages or grid leveling. But [Technology Connections] is taking this logic one step further. Since a large number of EV owners have charging stations built into their garages, he wondered if these charging stations could be used for other tasks and built an electric heater which can use one for power.

This project uses a level 2 charger, capable of delivering many kilowatts of power to an EV over fairly standard 240V home wiring with a smart controller in between that and the car. Compared to a level 1 charger which can only trickle charge a car on a standard 120V outlet (in the US) or a DC fast charger which can provide a truly tremendous amount of energy in a very short time, these are a happy middle ground. So, while it’s true a homeowner could simply wire up another 240V outlet for this type of space heater or other similar application, this project uses the existing infrastructure of the home to avoid redundancies like that.

Of course this isn’t exactly plug-and-play. Car chargers communicate with vehicles to negotiate power capabilities with each other, so any appliance wanting to use one as a bulk electric supply needs to be able to perform this negotiation. To get the full power available in this case all that’s needed is a resistor connected to one of the signal wires, but this won’t work for all cases and could overload smaller charging stations. For that a more complex signalling method is needed, but since this was more of a proof-of-concept we’ll still call it a success. For those wanting to DIY the charger itself, building one from the ground up is fairly straightforward as well.

Thanks to [Billy] for the tip!

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DIY Drones Deliver The Goods With Printed Release

January 22, 2025 by 17 Comments

It seems like the widespread use of delivery drones by companies like Amazon and Wal-Mart has been perpetually just out of reach. Of course robotics is a tricky field, and producing a fleet of these machines reliable enough to be cost effective has proven to be quite a challenge. But on an individual level, turning any drone into one that can deliver a package is not only doable but is something [Iloke-Alusala] demonstrates with their latest project.

The project aims to be able to turn any drone into a delivery drone, in this case using a FPV drone as the platform. Two hitch-like parts are 3D printed, one which adds an attachment point to the drone and another which attaches to the package, allowing the drone to easily pick up the package and then drop it off quickly. The real key to this build is the control mechanism. [Iloke-Alusala] used an ESP32 to tap into the communications between the receiver and the flight controller. When the ESP32 detects a specific signal has been sent to the flight controller, it can activate the mechanism on the 3D printed hitch to either grab on to a package or release it at a certain point.

While this is a long way from a fully autonomous fleet of delivery drones, it goes a long way into showing that individuals can use existing drones to transport useful amounts of material and also sets up a way for an ESP32 to decode and use a common protocol used in drones, making it easy to expand their capabilities in other ways as well. After all, if we have search and rescue drones we could also have drones that deliver help to those stranded.

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Hydroelectric Generator Gets Power From Siphoning

January 21, 2025 by 42 Comments

Siphons are one of those physics phenomena that, like gyroscopes, non-Newtonian fluids, and electricity, seem almost magical. Thanks to atmospheric pressure, simply filling a tube with liquid and placing the end of the tube below the liquid level of a container allows it to flow against gravity, over a barrier, and down into another container without any extra energy inputs once the siphon is started. They’re not just tricks, though; siphons have practical applications as well, such as in siphon-powered hydroelectric turbine.

This is an iteration of [Beyond the Print]’s efforts to draw useful energy from a local dam with an uneconomic amount of water pressure and/or volume for a typical hydroelectric power station. One of his earlier attempts involved a water wheel but this siphon-based device uses a more efficient impeller design instead, and it also keeps the generator dry as well. Using 3″ PVC piping to channel the siphon, as well as a short length of thinner pipe to attach a shop vac for priming the siphon, water is drawn from the reservoir, up the pipe, and then down through the impeller which spins a small DC generator.

This design is generating about 9 V open-circuit, and we’d assume there’s enough power available to charge a phone or power a small microcontroller device. However, there’s a ton of room for improvement here. The major problem [Beyond the Print] is currently experiencing is getting air into the system and having the siphon broken, which he’s solved temporarily by adding a bucket at the outflow. This slows down the water though, so perhaps with any air leaks mitigated the power generation capabilities will be greatly increased.

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Smallest USB Device… So Far

January 20, 2025 by 37 Comments

For better or worse it seems to be human nature to compete with one another, as individuals or teams, rather than experience contentedness while moving to the woods and admiring nature Thoreau-style. On the plus side, competition often results in benefits for all of us, driving down costs for everything from agriculture to medical care to technology. Although perhaps a niche area of competition, the realm of “smallest USB device” seems to have a new champion: this PCB built by [Emma] that’s barely larger than the USB connector pads themselves.

With one side hosting the pads to make contact with a standard USB type-A connector, the other side’s real estate is taken up by a tiny STM32 microcontroller, four phototransistors that can arm or disarm the microcontroller, and a tiny voltage regulator that drops the 5V provided by the USB port to the 3.3V the STM32 needs to operate. This is an impressive amount of computing power for less than three millimeters of vertical space, and can operate as a HID device with a wide variety of possible use cases.

Perhaps the most obvious thing to do with a device like this would be to build a more stealthy version of this handy tool to manage micromanagers, but there are certainly other tasks that a tiny HID can be put to use towards. And, as far as the smallest USB device competition goes, we’d also note that USB-A is not the smallest connector available and, therefore, the competition still has some potential if someone can figure out how to do something similar with an even smaller USB connector.

Thanks to [JohnU] for the tip!

New Frontiers For Nissan Leaf Motor And Battery

January 14, 2025 by 9 Comments

Nissan started off with a massive lead in the electric vehicle industry — their Leaf was the first mass-market EV available and the highest-selling EV until 2020. But the company has begun to lag behind other automotive manufacturers and their more diverse, modern offerings. As an example, the Leaf still doesn’t have active cooling for its battery packs. On the plus side, though, these cars are pretty easy to work on and parts for them are widely available. This includes the battery pack and motor, which can be dropped in to other non-EV Nissan products like this Nissan Frontier.

For conversions using the Leaf battery pack and motor, [Paul] points out that it’s important to find the motor with the inverter and power distribution unit all integrated together, rather than sourcing them all separately since they don’t always mix-and-match well. There are several third-party parts available for getting these motors running in other applications, including a coupler to mate the motor to a transmission. However, this still needs some custom fabrication to properly attach to the Frontier’s drivetrain. With a new controller as well, the Frontier engine can be pulled, the Leaf engine dropped in, and the battery set into the bed and connected.

A followup video shows [Paul] driving his new EV down a neighborhood street, but it looks like there are still a few things to polish up before it’s ready to hit the open highway including a more robust housing for the battery. But, if donor vehicles can be found like a truck body and Leaf drivetrain components, this type of modification can be done for a surprisingly small cost. These EV batteries can also be put to work as home power banks as well.

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Bit-Banging The USB-PD Protocol

January 10, 2025 by 14 Comments

For one-off projects, adding a few integrated circuits to a PCB is not too big of a deal. The price of transistors is extremely low thanks to Moore and his laws, so we’re fairly free to throw chips around like peanuts. But for extremely space-constrained projects, huge production runs, or for engineering challenges, every bit of PCB real estate counts. [g3gg0] falls into the latter group, and this project aims to remove the dedicated USB-PD module from a lighting project and instead bit-bang the protocol with the ESP32 already on the board.

The modern USB power delivery (PD) protocol isn’t quite as simple as older USB ports that simply present a 5V source to whatever plugs itself into the port. But with the added complexity we get a lot more capability including different voltages and greater power handling capabilities. The first step with the PD protocol is to communicate with a power source, which requires a 1.2V 600kHz signal. Just generating the signal is challenging enough, but the data encoding for USB requires level changes to encode bits rather than voltage levels directly. With that handled, the program can then move on to encoding packets and sending them out over the bus.

After everything is said and done, [g3gg0] has a piece of software that lets the ESP32 request voltages from a power supply, sniff and log PD communication, and inject commands with vendor defined messages (VDM), all without needing to use something like a CH224K chip which would normally offload the USB-PD tasks. For anyone looking to save PCB space for whatever reason, this could be a valuable starting point. To see some more capabilities of the protocol, check out this USB-PD power supply that can deliver 2 kW.