PCB Linear Motors For Model Trains

May 19, 2022 by Anne Ogborn 34 Comments

Modeling a railroad is hard. Railroads are large, linear pieces of civil engineering. So many modelers are drawn to the smallest scale they can use. Recently a new scale, named T, at 1:450 has been pushing this barrier. But fitting a reliable mechanical drive mechanism and MCU board in a package this size is a challenge. In practice, even more of a problem is getting reliable electrical contact through a metal wheel on metal track (about the worst possible design for a contact).

T always seemed to us a long way out on the bleeding edge. But all that may have changed. In a recent Hackaday.io writeup, author [Martin] describes a PCB technology based linear motor system to externally drive T scale locomotives.

The system uses 4mm planar coils. The underside of the PCB has another coil, so the effective pitch is 2mm. With microstepping, a step of 0.25mm is possible, and trains run smoothly. Current is 3-400mA. Continue reading “PCB Linear Motors For Model Trains” →

Scott’s CPU From The Bottom Up

May 19, 2022 by Al Williams 5 Comments

It isn’t for everyone, but if you work much with computers at a low level, you’ll probably sooner or later entertain the idea of creating your own CPU. There was a time when that was a giant undertaking, but with today’s tools and FPGAs it is… well, not easy, but certainly easier. If you have the urge to try your own, you might have a look at [Simply Explained’s] video series called “Building Scott’s CPU.”

The 11 videos cover everything from basic transistor logic to sequential circuits and moves on to things like ALUs, clock units, and how jump instructions work.

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Flexible Grip For Hammer Made With 3D Printing Pen

May 19, 2022 by Lewin Day 17 Comments

When it comes to putting a flexible grip on a tool, you might reach for a self-fusing silicone tape or other similar product. However, [Potent Printables] has discovered you can easily create a flexible grip using a 3D-printing pen and some flex filament.

In this case, a hammer first gets a layer of blue painters tape wrapped around its wooden handle. This serves as a base layer to promote good adhesion. A simple paper template was then printed as a guide for creating the graphics on the flexible grip. Flexible filament was fed through the 3D pen, with the red and black details of the graphics printed first. Then, white flex filament was used to make the rest of the flexible grip. A wood burning tool was then used to smooth out the first layer of flex filament, before a second layer was added on top.

The result is a flexible white grip on the hammer which is stuck fast, likely due to shrinkage as the plastic cooled after printing. We’ve seen some other creative grips made with 3D printing before, too. Video after the break.

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OpenCV Running On A Tiny Microcontroller

May 19, 2022 by Bryan Cockfield 10 Comments

At first blush, it might seem like projects that make extensive use of computer vision or machine learning would need to be based on powerful computing platforms with plenty of clock cycles and memory to handle this type of application. While there is some truth to this, as the field progresses it becomes possible to experiment with these tools on low-power devices as well. Take this OpenCV project which is built entirely on an ESP32 for example.

With that being said, there are some modifications that need to be made to the ESP32 in order to use OpenCV in any meaningful way. The most important of these is the use of the ESP32-DOWDQ6 module which increases the available memory of the ESP32 to allow it to make better use of camera functions. Even then, the ESP32 can’t run the entire OpenCV application, so a shrunken version of OpenCV is required before the device can run it natively. Once those two obstacles are out of the way, though, doing things like edge detection, as this project demonstrates, are well in the realm of possibility.

If running OpenCV on something as small as an ESP32 is possible, it is even easier to run on something orders of magnitude more powerful and yet still inexpensive, such as the Raspberry Pi. While the project’s code is available on its GitHub page for those interested, there are plenty of other OpenCV projects that we have featured on more powerful platforms as well, like this clock which falls off of the wall whenever someone looks at it.

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Hacking The Logitech Z906 Speaker System

May 19, 2022 by Lewin Day 42 Comments

The Logitech Z906 is a well-rounded 5.1 surround sound system. It’s capable of putting out 1000W in peak power, and can decode Dolby Digital and DTS soundtracks as you’d expect. It’s intended to be used as the heart of a home cinema system and used with a central command console. However, [zarpli] figured out the device’s serial secrets and can now run the device in a standalone manner.

As it turns out, the Z906 uses a main control console that speaks to the rest of the hardware over a DE15 connector (also known as the DB-15). [zarpli] realized that the hardware could instead be commanded by just about any device with a serial port. Thus, a library was whipped up that can be readily used with an Arduino to control all the major functions of the Z906. Everything from volume levels to effect modes and channel assignments can be commanded by microcontroller. As a finale, [zarpli] shows off the hardware playing a multi-channel composition without the console connected, with his own hardware running the show instead.

If you’ve got a Logitech Z906 or similar unit that you wish to automate, you might find this work useful. It’s also a good inspiration for anyone contemplating hacking away at the console ports on other hardware. Video after the break.

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Put A New Spin On Your 3D Printed Parts

May 19, 2022 by Al Williams 4 Comments

Once you get tired of printing keychains and earbud holders with your 3D printer, you’ll want to design things a bit more sophisticated. How about things that rotate? [3DSage] has a good how-to about how to integrate a simple motor and controller into a few different size boxes. Combined with some 3D printed linkages, these boxes can turn your project — printed or otherwise — into something that spins.

To demonstrate, he created a few cat toys, played with an idea for a magic trick, and refit a selfie light into… something. We have no doubt you can find something to do with these little motor modules. The boxes vary mostly in how big the battery packs are. There are also several interesting side pieces like a 3D holder for rechargeable button cells and their charger.

In addition, he also demonstrates how to use the motor as a (rather poor) generator. Attaching a water wheel wasn’t a success until he used compressed air to run the wheel. You would have thought water would have done the trick.

The video stresses that you should solder connections, but you don’t have to. Honestly, we think if you are building moving stuff with a 3D printer, you should probably just go ahead and learn to solder. It isn’t that hard and there are plenty of reasons to learn.

Of course, you could 3D print the motor itself. Adapting motor modules for different uses isn’t a new idea, of course, but it is always great to see more ways to apply basic components.

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Water Your Plants Just Four Times Per Year

May 19, 2022 by Kristina Panos 20 Comments

While it’s true that some plants thrive on neglect, many of them do just fine with a few ounces of water once a week, as long as the light level is right. But even that is plenty to remember and actually do in our unprecedented times, so why bother trying? [Martin] has solved this problem for us, having given every aspect of automatic plant care a lot of thought. The result of his efforts is Flaura, a self-watering open-source plant pot, and a YouTube channel to go with it.

The 3D-printed pot can easily be scaled up or down to suit the size of the plant, and contains a water reservoir that holds about 0.7 L of water at the default size. Just pour it in through the little spout, and you’re good for about three months, depending on the plant, the light it’s in, and how much ~~current~~ water it draws. You can track the dryness level in the companion app.

Whenever the capacitive soil moisture sensor hidden in the bottom of the dirt detects drought conditions, it sends a signal through the Wemos LOLIN32 and a MOSFET to a small pump, which sends up water from the reservoir.

The soil is watered uniformly by a small hose riddled with dozens of tiny holes that create little low-pressure water jets. This is definitely our favorite part of the project — not just because it’s cool looking, but also because a lot of these types of builds tend to release the water in the same spot all the time, which is. . . not how we water our plants. Be sure to check out the project overview video after the break.

No printer? No problem — you could always use an old Keurig machine to water a single plant, as long as the pump is still good.

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