Friday Hack Chat: Training Robots By Touch

When it comes to training robots, you could grab a joystick or carefully program movements in code. The better way, though, is to move the robot yourself, and have the robot play back all those movements ad infinitum. This is training robots by touch, and it’s the subject of this week’s Hack Chat over on hackaday.io.

Our guest for this week’s Hack Chat will be [Kent Gilson], inventor, serial entrepreneur, and pioneer in reconfigurable computing. [Kent] is the creator of Viva, an object-oriented programming language and operating environment that harnesses the power of FPGAs into general-purpose computing He’s launched eight entrepreneurial ventures, won multiple awards, and created products used in numerous industries across the globe.

[Kent]’s claim to fame on hackaday.io is Dexter, a low-cost robotic arm with 50-micron repeatability and modular end effectors. It does this with three harmonic drives and optical encoders that give it extreme precision. The arm is also trainable, meaning that you can manually control it and play back the exact path it took. It’s training robots by touch, exactly what this Hack Chat is all about.

For this Hack Chat, we’re going to be discussing:

  • Building trainable robots
  • Developing robotics haptics
  • Training robots to manufacture
  • Heterogenous direct digital manufacturing

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the Hack Chat Event Page and we’ll put that in the queue for the Hack Chat discussion.join-hack-chat

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week is just like any other, and we’ll be gathering ’round our video terminals at noon, Pacific, on Friday, July 27th.  Need a countdown timer? Well, here you go, mango.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Watney: A Fully 3D Printed Rover Platform

We’re getting to the point that seeing 3D printed parts in a project or hack isn’t as exciting as it was just a few years ago. The proliferation of low-cost desktop 3D printers means that finding a printer to squirt out a few parts for your build isn’t the adventure it once was. Gone are the days of heading to a local hackerspace or college hoping their janky Mendel felt like working that day. But all that really means is that hackers and makers now have the ability to utilize 3D printing even more. Forget printing one or two parts of your design, just print the whole thing.

That’s exactly what [Nik Ivanov] did with Watney, his fully 3D printed rover project. After lamenting that many so-called 3D printed rovers were anything but, he set out to design one that was not only made primarily of printed parts, but was robust enough to put some real work in. Over the course of several design iterations, he built a very capable all-wheel drive platform that needs only some electronics and a handful of M3 screws to leap into action.

As long as you’ve got a 3D printer big enough to handle the roughly 120mm x 190mm dimensions of this bot’s body, you’re well on the way to owning your very own video rover. [Nik] recommends printing everything in PETG, no doubt for its increased strength when it comes to things like the drive gears. Plus it’s low warp, which is really going to help when printing the top and bottom sections of the body. TPU is advised for the tires, but if you don’t have any (or your printer chokes on flexible filaments) you can just wrap the wheels with wide rubber bands.

[Nik] is using a Raspberry Pi Zero W as the brains of the operation, but the beauty of an open platform like this is that you could easily swap out the controls for something else to meet your needs. In addition to the Pi, there’s a L298N H-bridge motor controller to interface with the dual geared motors, as well as a servo to provide tilt for the SainSmart camera module.

We’ve often been surprised at just how expensive commercial robotics platforms can be, so we’re keenly interested in seeing if the availability of designs like this spur on DIY rover development. Though if you’re looking for something a little more rough and tumble, we’ve seen a 3D printed rover that looks combat-ready.

Continue reading “Watney: A Fully 3D Printed Rover Platform”

Robotic Muscles from Fishing Line and Nichrome

Did you know that under the right conditions, nylon can be used as a type of artificial muscle? We certainly didn’t until we came across [Brandon T. Wood]’s Material Linear-Actuator for Robotics entry for the 2018 Hackaday Prize.

When [Brandon] first learned about Nylon Linear Material Actuators (NLMAs), he became determined to find a repeatable and practical method of making and experimenting with them. This is how it works: hyper-wound coils of nylon, when heated, will contract along their length while expanding in width. Upon cooling, they return to their original shape.

[Brandon] has been busy mainly with the kind of work that is important but not very flashy: finding accessible methods to reliably create strands of artificial nylon muscles cheaply and reliably. His current method uses a jig to wind nylon fishing line until it coils upon itself tightly, then twist a length of nichrome wire around the outside to act as a heater. Using this method, the coils can be electrically controlled. [Brandon] is currently experimenting with creating bundles of individual nylon coils to act all together as one big muscle, because while one wire isn’t particularly strong, a bundle could be quite another story. It’s definitely unusual and is doing a lot of work to turn a known phenomenon into something hackable, which makes it lovely to see in this year’s Hackaday Prize.

Hold the Salt and Butter, This Popcorn Is For a Robot

Popcorn! Light and fluffy, it is a fantastically flexible snack. We can have them plain, create a savory snack with some salt and butter, or cover with caramel if you have a sweet tooth. Now Cornell University showed us one more way to enjoy popcorn: use their popping action as the mechanical force in a robot actuator.

It may be unorthodox at first glance, but it makes a lot of sense. We pop corn by heating its water until it turns into steam triggering a rapid expansion of volume. It is not terribly different from our engines burning an air-fuel mixture to create a rapid expansion of volume. Or using heat energy to boil water and trigger its expansion to steam. So a kernel of popcorn can be used as a small, simple, self-contained engine for turning heat energy into mechanical power.

Obviously it would be a single-use mechanism, but that’s perfectly palatable for the right niche. Single-use is a lot easier to swallow when popcorn is so cheap, and also biodegradable resulting in minimal residue. The research paper demonstrated three recipes to harness popping corn’s mechanical energy, but that is hardly an exhaustive list. There’s an open invitation to brainstorm other creations to add to the menu.

Of course, if you prefer candy over popcorn, you could build a robot actuator out of licorice instead.

Either way, the robot uprising will be delicious.

[via IEEE Spectrum]

Continue reading “Hold the Salt and Butter, This Popcorn Is For a Robot”

3D Printed Arduino Bot is Limbo Master

As if we didn’t have enough to worry about in regards to the coming robot uprising, [Ali Aslam] of Potent Printables has recently wrapped up work on a 3D printed robot that can flatten itself down to the point it can fit under doors and other tight spaces. Based on research done at UC Berkeley, this robot is built entirely from printed parts and off the shelf hardware, so anyone can have their own little slice of Skynet.

On display at East Coast RepRap Festival

The key to the design are the folding “wings” which allow the robot to raise and lower itself on command. This not only helps it navigate tight spaces, but also gives it considerable all-terrain capability when it’s riding high. Rather than wheels or tracks, the design uses six rotors which look more like propellers than something you’d expect to find on a ground vehicle. These rotors work at the extreme angles necessary when the robot has lowered itself, and allow it to “step” over obstructions when they’re vertical.

For the electronics, things are about what you’d expect. An Arduino Pro Mini combined with tiny Pololu motor controllers is enough to get the bot rolling, and a Flysky FS-X6B receiver is onboard so the whole thing can be operated with a standard RC transmitter. The design could easily be adapted for WiFi or Bluetooth control if you’d rather not use RC gear for whatever reason.

Want to build your own? All of the STL files, as well as a complete Bill of Materials, are available on the Thingiverse page. [Ali] even has a series of videos on YouTube videos walking through the design and construction of the bot to help you along. Outside of the electronics, you’ll need a handful of screws and rods to complement the 50+ printed parts. Better start warming up the printer now.

As an interesting aside, we got a chance to see this little critter first hand at the recent East Coast RepRap Festival in Maryland, along with a number of other engineering marvels.

Continue reading “3D Printed Arduino Bot is Limbo Master”

Raspberry Pi Zero Stepper Driver, First of Many Modules

The Raspberry Pi in general (and the Zero W model in particular) are wonderful pieces of hardware, but they’re not entirely plug-and-play when it comes to embedded applications. The user is on the hook for things like providing a regulated power source, an OS, and being mindful of proper shutdown and ESD precautions. Still, the capabilities make it worth considering and [Alpha le ciel] has a project to make implementation easier with the Raspberry Pi Zero W Stepper Motor Module, which is itself part of a larger project plan to make the Pi Zero W into a robust building block for robotic and CNC applications.

[Alpha le ciel] is building this stepper motor module as the first of many Raspberry Pi hats meant to provide the Raspi with the hardware for robotics applications. This module, in particular, features two A4988 stepper motor drivers, a connector for a power supply or battery providing 7-20V, and a buck converter to bring that power down to the 5V needed by the Pi itself. All the relevant pins are broken out onto the Pi’s GPIO header, making this module the simplest way possible to add a pair of motors to a Pi. What does that mean? Printers or self-balancing robots, really whatever you want.

A stepper driver that conforms to the footprint of the Pi Zero is a good start, and the larger concept of creating additional modules is a worthy entry to the Hackaday Prize.

Adding Smarts To Dumb Brushed Motors

A big part of the Hackaday Prize this year is robotics modules, and already we’ve seen a lot of projects adding intelligence to motors. Whether that’s current sensing, RPM feedback, PID control, or adding an encoder, motors are getting smart. Usually, though, we’re talking about fancy brushless motors or steppers. The humble DC brushed motor is again left out in the cold.

This project is aiming to fix that. It’s a smart motor driver for dumb DC brushed motors. You know, the motors you can buy for pennies. The motors that are the cheapest way to add movement to any project. Those motors.

The Smart Motor Driver for Robotics allows a DC brushed motor to be controlled by a host microcontroller over I2C, and sends back the speed and direction of the motor. PID is implemented, and the motor can maintain its own speed, independently of a lot of difficult control on the host system.

The guts of this motor controller are made of a PIC 12F microcontroller, a H-bridge motor driver, a Hall-effect sensor, and a neat magnetic encoder disc. Ultimately, this project will simply bolt onto the back of a cheap brushed motor and give it the same capabilities as a fancy servo or stepper. It’s never going to have the same torque or power handling as a beefy NEMA 17 stepper, but sometimes you don’t need that, and a simple brushed motor will do. A great project, and an excellent entry for the Hackaday Prize.