Video Shows Power Isn’t Everything In Laser Engraving

October 11, 2018 by Donald Papp 22 Comments

When it comes to power tools, generally speaking more watts is better. But as laser maestro [Martin Raynsford] shows, watts aren’t everything. He shares a brief video showing his older 100 W laser being handily outperformed by a newer 30 W machine. Shouldn’t the higher power laser be able to do the same job in less time? One might think so, but wattage isn’t everything. The 30 W laser engraves and cuts a wooden tile in just under half the time it takes the 100 W machine to do the same job, and with a nicer end result, to boot.

Why such a difference? Part of the answer to that question lies in that the newer machine has better motion control and can handle higher speeds, but the rest is due to the tubes themselves. The older 100 W machine uses a DC-excited (big glass water-cooled tube) CO2 laser, and the newer 30 W machine uses an RF-excited laser that looks a bit like a big metal heat sink instead of oversized lab glassware. Both tubes output what is essentially the same beam, but the RF tube is overall capable of a more refined, more stable, and more finely focused point than that of the glass tube. Since engraving uses only a small fraction of even the 30 W laser’s power, the finer control that the RF laser has over the low end of the power scale results in a much higher quality engraving.

Embedded below is a short video showing both machines engraving and cutting the same tile, side by side. You may wish to consider watching this one full screen, to better see the fine details.

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One-Legged Jumping Robot Shows That Control Is Everything

October 9, 2018 by Donald Papp 29 Comments

Robots that can jump have been seen before, but a robot that jumps all the time is a little different. Salto-1P is a one-legged jumping robot at UC Berkeley, and back in 2017 it demonstrated the ability to hop continuously with enough control to keep itself balanced. Since then it has been taught some new tricks; having moved beyond basic stability it can now jump around and upon things with an impressive degree of control.

Key to doing this is the ability to plant its single foot exactly where it wants, which allows for more complex behaviors such as hopping onto and across different objects. [Justin Yim] shows this off in the video embedded below, which demonstrates the Salto-1P bouncing around in a remarkably controlled fashion, even on non-ideal things like canted surfaces. Two small propellers allow the robot to twist in midair, but all the motive force comes from the single leg.

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Pocket High Voltage Generator Becomes Great Test Tool

October 8, 2018 by Donald Papp 4 Comments

[The LED Artist] often found a need for a relatively high voltage (100 to 200 Volt) but low current DC power supply, and it turns out that a small HV generator that uses a single AA cell only took about an hour to make. The device ended up being a pretty handy tool for testing things like LED filaments (which have a forward voltage of over 60 V), or even neon and nixie tubes.

The device’s low current means that nixie and neon elements won’t light up very brightly, but they will light up enough to verify function and operation. [The LED Artist] reports that touching the output terminals of the generator only causes a slight tingling sensation.

Open-circuit voltage generated from a single AA cell is about 200 V, but that voltage drops rapidly under any kind of load. Even regular LEDs can be safely lit with the circuit, with less than a milliamp being supplied at the two to three volts at which most regular LEDs operate.

[The LED Artist] fit the device into a two-AA battery holder, with a single AA cell on one side and the circuit in the other, and says it’s one of the more useful tools they’ve ever made. LED filaments are fairly common nowadays, but if they intrigue you, don’t forget that [Mike Harrison] covered everything you need to know about experimenting with them.

SENSEation Shows The Importance Of Good Physical Design

October 4, 2018 by Donald Papp 1 Comment

Sensor network projects often focus primarily on electronic design elements, such as architecture and wireless transmission methods for sensors and gateways. Equally important, however, are physical and practical design elements such as installation, usability, and maintainability. The SENSEation project by [Mario Frei] is a sensor network intended for use indoors in a variety of buildings, and it showcases the deep importance of physical design elements in order to create hardware that is easy to install, easy to maintain, and effective. The project logs have an excellent overview of past versions and an analysis of what worked well, and where they fell short.

One example is the power supply for the sensor nodes. Past designs used wall adapters to provide constant and reliable power, but there are practical considerations around doing so. Not only do power adapters mean each sensor requires some amount of cable management, but one never really knows what one will find when installing a node somewhere in a building; a power outlet may not be nearby, or it may not have any unoccupied sockets. [Mario] found that installations could take up to 45 minutes per node as a result of these issues. The solution was to move to battery power for the sensor nodes. With careful power management, a node can operate for almost a year before needing a recharge, and removing any cable management or power adapter meant that installation time dropped to an average of only seven minutes.

That’s just one example of the practical issues discovered in the deployment of a sensor network in a real-world situation, and the positive impact of some thoughtful design changes in response. The GitHub repository for SENSEation has all the details needed to reproduce the modular design, so check it out.

The Magic Flute Of Rat Mind Control Aims To Mix Magic And Science

October 3, 2018 by Donald Papp 16 Comments

Well this is unusual. Behold the Magic Flute of Rat Mind Control, and as a project it is all about altering the response to the instrument, rather than being about hacking the musical instrument itself. It’s [Kurt White]’s entry to the Musical Instrument Challenge portion of The Hackaday Prize, and it’s as intriguing as it is different.

The Raspberry-Pi controlled, IoT Skinner box for rats, named *Nicodemus*.

[Kurt] has created a portable, internet-connected, automated food dispenser with a live streaming video feed and the ability to play recorded sounds. That device (named Nicodemus) is used as a Skinner Box to train rats — anywhere rats may be found — using operant conditioning to make them expect food when they hear a few bars of Black Sabbath’s Iron Man played on a small recorder (which is a type of flute.)

In short, the flute would allow one to summon hordes of rats as if by magic, because they have been trained by Nicodemus to associate Iron Man with food.

Many of the system’s elements are informed by the results of research into sound preference in rats, as well as their ability to discriminate between different melodies, so long as the right frequencies are present. The summoning part is all about science, but what about how to protect oneself from the hordes of hungry rodents who arrive with sharp teeth and high expectations of being fed? According to [Kurt], that’s where the magic comes in. He seems very certain that a ritual to convert a wooden recorder into a magic flute is all the protection one would need.

Embedded below is something I’m comfortable calling the strangest use case video we’ve ever seen. Well, we think it’s a dramatized use case. Perhaps it’s more correctly a mood piece or motivational assist. Outsider Art? You decide.

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Watch The Snappy, Insect-like Moves Of This DIY Quadruped Robot

September 30, 2018 by Donald Papp 28 Comments

Some legged robots end up moving with ponderous deliberation, or wavering in unstable-looking jerks. A few unfortunates manage to do both at once. [MusaW]’s 3D Printed Quadruped Robot, on the other hand, moves in rapid motions that manage to look sharp and insect-like instead of unstable. Based on an earlier design he made for a 3D printable quadruped frame, [MusaW] has now released this step-by-step guide for building your own version. All that’s needed is the STL files and roughly $50 in parts from the usual Chinese resellers to have the makings of a great weekend project.

The robot uses twelve SG90 servos and an Arduino nano with a servo driver board to control them all, but there’s one additional feature: Wi-Fi control is provided thanks to a Wemos D1 Mini (which uses an ESP-8266EX) acting as a wireless access point to serve up a simple web interface through which the robot can be controlled with any web browser.

Embedded below is a brief video. The first half is assembly, and the second half demonstrates the robot’s fast, sharp movements.

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Gesture Control Without Fancy Sensors, Just Pots And Weights

September 29, 2018 by Donald Papp 3 Comments

[Dennis] aims to make robotic control a more intuitive affair by ditching joysticks and buttons, and using wireless gesture controls in their place. What’s curious is that there isn’t an accelerometer or gyro anywhere to be seen in his Palm Power! project.

The gesture sensing consists not of a fancy IMU, but of two potentiometers (one for each axis) with offset weights attached to the shafts. When the hand tilts, the weights turn the shafts of the pots, and the resulting readings are turned into motion commands and sent over Bluetooth. The design certainly has a what-you-see-is-what-you-get aspect to it, and as a whole it works much like an inverted, weighted joystick hanging from one’s palm.

It’s an economical way to play with the idea of motion sensing, and when it comes to prototyping, being able to test a concept while keeping costs to a minimum is a good skill to have.