Posts with «servo» label

Automatic Sunglasses, The Electromechanical Way

These days, photochromic lenses are old-hat. Sure, it’s useful to have a pair of glasses that automatically tints due to UV light, but what if you want something a little more complex and flashy? Enter [Ashraf Minhaj]’s SunGlass-Bot.

The build is simple, beginning with an Arduino Pro Mini for reasons of size. Connected to the analog input is a light-dependent resistor for sensing the ambient light level. This reading is then used to decide whether or not to move the servo which controls the position of the lenses. In low light, the lenses are flipped up to allow clear vision; in brighter light, the lenses flip down to protect the eyes. Power is supplied by a homebrew powerbank that it appears [Ashraf] built from an old phone battery and a small boost converter board. All the files to recreate the project are available on Github, too.

It’s a fun build that [Ashraf] shows off in style. While this may not be as effortless as a set of Transition lenses or as quick as a welding mask filter, it has a certain mechanical charm that wouldn’t be out-of-place in a certain sci-fi aesthetic.

Hungry for more? Check out these self-blending sunglasses we featured a while back. Video after the break.

Supersize DIY R/C Servos From Windscreen Wipers

We’re all familiar with the experience of buying hobby servos. The market is awash with cheap clones which have inflated specs and poor performance. Even branded servos often fail to deliver, and sometimes you just can’t get the required torque or speed from the small form factor of the typical hobby servo.

Enter [James Bruton] and his DIY RC servo from a windscreen wiper motor. Windscreen wiper motors are cheap as chips, and a classic salvage. The motor shaft is connected to a potentiometer via a pulley and some string, providing the necessary closed-loop feedback. Instead of using the traditional analog circuitry found inside a servo, an Arduino provides the brains. This means PID control can be implemented on the ‘duino, and tuned to get the best response from different load characteristics. There’s also the choice of different interfacing options: though [James]’ Arduino code accepts PWM signals for a drop-in R/C servo replacement, the addition of a microcontroller means many other input signal types and protocols are available. In fact, we recently wrote about serial bus servos and their numerous advantages.

We particularly love this because of the price barrier of industrial servomotors; sure, this kind of solution doesn’t have the precision or torque that off-the-shelf products provide, but would be sufficient for many hacks. Incidentally, this is what inspired one of our favourite open source projects: ODrive, which focuses on harnessing the power of cheap brushless motors for industrial use.

The Sensor Array That Grew Into a Robot Cat

Human brains evolved to pay extra attention to anything that resembles a face. (Scientific term: “facial pareidolia”) [Rongzhong Li] built a robot sensor array with multiple emitters and receivers augmenting a Raspberry Pi camera in the center. When he looked at his sensor array, he saw the face of a cat looking back at him. This started his years-long Petoi OpenCat project to build a feline-inspired body to go with the face.

While the name of the project signals [Rhongzhong]’s eventual intention, he has yet to release project details to the open-source community. But by reading his project page and scrutinizing his YouTube videos (a recent one is embedded below) we can decipher some details. Motion comes via hobby remote-control servos orchestrated by an Arduino. Higher-level functions such as awareness of environment and Alexa integration are handled by a Raspberry Pi 3.

The secret (for now) sauce are the mechanical parts that tie them all together. From impact-absorption spring integrated into the upper leg to how its wrists/ankles articulate. [Rongzhong] believes the current iteration is far too difficult to build and he wants to simplify construction before release. And while we don’t have much information on the software, the sensor array that started it all implies some level of sensor fusion capabilities.

We’ve seen lots of robotic pets, and for some reason there have been far more robotic dogs than cats. Inspiration can come from Boston Dynamics, from Dr. Who, or from… Halloween? We think the lack of cat representation is a missed opportunity for robotic pets. After all, if a robot cat’s voice recognition module fails and a command is ignored… that’s not a bug, it’s a feature of being a cat.

[via TheNextWeb]

Turtlebyte

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What does it do?

Autonomous robot pet

3/6/18- Just finished the front legs! Woohoo! I did several test runs on one of them, the most recent being documented in the video. But I screwed up the movement range in the test Arduino sketches, since the servos can no longer rotate fully. I hope I didn’t strain the servo too bad...

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Afroman Teaches Intro to Servos, Builds Laser Turret

After a longish hiatus, we were pleased to see a new video from [Afroman], one of the most accessible and well-spoken teachers the internet has to offer. If you’re new to electronics, see the previous sentence and resolve to check out his excellent videos. The new one is all about servos, and it culminates in a simple build that provides a foundation for exploring robotics.

[Afroman] leaves no gear unturned in his tour de servo, which is embedded after the break. He explains the differences between open vs. closed loop motor systems, discusses the different sizes and types of servos available, and walks through the horns and pigtails of using them in projects. Finally, he puts this knowledge to use by building a laser turret based on a pan-tilt platform.

The Arduino-driven turret uses two micro servos controlled with pots to move by degrees in X/Y space. Interestingly, [Afroman] doesn’t program the board in the Arduino IDE using wiring. Instead, he uses an open-source microcontroller language/IDE called XOD that lets you code by building a smart sort of schematic from drag-and-drop components and logic nodes. Draw the connections, assign your I/O pin numbers, and XOD will compile the code and upload it directly to the board.

XOD seems like a good tool for beginners to do rapid prototyping. On the other hand, a look into the generated code reveals a whole lot of wrappers that obfuscate the bits of code that actually do stuff. There doesn’t seem to be a way to shed them, either, so once you design something in XOD, you’re kind of stuck using it to iterate. That said, the generated code is well documented, and someone who knows what they’re looking at could find, for instance, the I/O pin assigned to the blink sketch LED.

Once the novelty of the double laser cat tormentor has subsided, use the other servos in that 5-pack you bought to flip a light switch, control a knob, or play the glockenspiel.


Filed under: how-to, Laser Hacks

Design and 3D Print Robots with Interactive Robogami

Internals of 3D printed “print and fold” robot. [Image source: MIT CSAIL]
Robot design traditionally separates the body geometry from the mechanics of the gait, but they both have a profound effect upon one another. What if you could play with both at once, and crank out useful prototypes cheaply using just about any old 3D printer? That’s where Interactive Robogami comes in. It’s a tool from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) that aims to let people design, simulate, and then build simple robots with a “3D print, then fold” approach. The idea behind the system is partly to take advantage of the rapid prototyping afforded by 3D printers, but mainly it’s to change how the design work is done.

To make a robot, the body geometry and limb design are all done and simulated in the Robogami tool, where different combinations can have a wild effect on locomotion. Once a design is chosen, the end result is a 3D printable flat pack which is then assembled into the final form with a power supply, Arduino, and servo motors.

A white paper is available online and a demonstration video is embedded below. It’s debatable whether these devices on their own qualify as “robots” since they have no sensors, but as a tool to quickly prototype robot body geometries and gaits it’s an excitingly clever idea.

Perhaps there’s an opportunity to enhance the “3D print, then fold” approach Robogami uses with this concept for making flexible prints out of non-flexible material, or incorporating simple 3D printed circuitry.

Thanks to [Adam] for the tip!


Filed under: robots hacks

Design and 3D Print Robots with Interactive Robogami

Internals of 3D printed “print and fold” robot. [Image source: MIT CSAIL]
Robot design traditionally separates the body geometry from the mechanics of the gait, but they both have a profound effect upon one another. What if you could play with both at once, and crank out useful prototypes cheaply using just about any old 3D printer? That’s where Interactive Robogami comes in. It’s a tool from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) that aims to let people design, simulate, and then build simple robots with a “3D print, then fold” approach. The idea behind the system is partly to take advantage of the rapid prototyping afforded by 3D printers, but mainly it’s to change how the design work is done.

To make a robot, the body geometry and limb design are all done and simulated in the Robogami tool, where different combinations can have a wild effect on locomotion. Once a design is chosen, the end result is a 3D printable flat pack which is then assembled into the final form with a power supply, Arduino, and servo motors.

A white paper is available online and a demonstration video is embedded below. It’s debatable whether these devices on their own qualify as “robots” since they have no sensors, but as a tool to quickly prototype robot body geometries and gaits it’s an excitingly clever idea.

Perhaps there’s an opportunity to enhance the “3D print, then fold” approach Robogami uses with this concept for making flexible prints out of non-flexible material, or incorporating simple 3D printed circuitry.

Thanks to [Adam] for the tip!


Filed under: robots hacks

Zero-Intrusion Wireless Light Switch

What do you do if your light switch is too far from your desk, and you’re in a rental property so you can’t put in extra wiring to install an electronic control for it? Get up and turn it on or off by hand? Of course not!

If you are [Guyfromhe], you solve this problem with a servo attached to a screw-on light switch faceplate, and you control it with a pair of Arduino/nRF24L01 combos. It’s a pretty simple arrangement, the wireless link simply takes the place of a serial cable that instructs the Arduino on the light switch to operate the servo that in turn moves the switch. The whole thing is triggered through his home automation system, which in turn responds to an Amazon Dash button on his desk. Yes, it’s complex. But turning on the light has been automated without intrusion into his landlord’s domain, and that’s all that matters.

On a more serious note, he’s put some Arduino code up on his write-up, as well as a YouTube video we’ve put below the break.

This is by no means the first such switch we’ve seen, after all we featured a nicer 3D printed servo light switch the other month, and one with a breadboarded Arduino in 2015. While we’re at it though, it would be nice to see a few designed for European switches too.


Filed under: home hacks

Arduino + Geometry + Bicycle = Speedometer

It is pretty easy to go to a big box store and get a digital speedometer for your bike. Not only is that no fun, but the little digital display isn’t going to win you any hacker cred. [AlexGyver] has the answer. Using an Arduino and a servo he built a classic needle speedometer for his bike. It also has a digital display and uses a hall effect sensor to pick up the wheel speed. You can see a video of the project below.

[Alex] talks about the geometry involved, in case your high school math is well into your rear view mirror. The circumference of the wheel is the distance you’ll travel in one revolution. If you know the distance and you know the time, you know the speed and the rest is just conversions to get a numerical speed into an angle on the servo motor. The code is out on GitHub.

Granted, reading a magnet, keeping time, and driving a servo isn’t exactly cutting edge. On the other hand, it made us think about what other kinds of outputs you could drive. We haven’t seen a nixie tube speedometer (well, not on a bicycle, anyway), for example. Or maybe one built with mechanical flip numbers like an old clock.

We have seen some with Arduinos and lots of LEDs (although, again, not really for a bicycle). This speedometer might still be our favorite, though.

 


Filed under: Arduino Hacks, transportation hacks

Tertiarm - low cost, 3d printed robot arm based on Ikea lamp

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Move things, push buttons, etc.

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Let's Make Robots 07 Feb 15:54