R/C Bot Takes Your Strawberries Away

July 10, 2016 by Steven Dufresne 16 Comments

Don’t let the friendly smile on this RC cart fool you, it will take your strawberries away — though that’s kinda the point. It’s an RC car that [transistor-man] and a few friends modified for carrying freshly picked strawberries at strawberry fields so that you don’t have to.

RC strawberry carrying robot before putting on the cooler — RC strawberry carrying robot – WIP

They started with an older Traxxas Emaxx, a 4-wheel drive RC monster truck. The team also bought a suitable sized water cooler at a local hardware store. A quick load test showed that 5lbs collapsed the springs and shock absorbers, causing the chassis to sink close to the ground. The team had two options: switching to stronger springs or locking out the springs altogether. They decided to replace one set of shocks with metal plates effectively locking them. After that it was time for some CAD work, followed by the use of a water jet to cut some aluminum plate. They soon had a mounting plate for the water cooler to sit in. This mounting plate was attached to 4 posts which originally held the vehicle’s Lexan body. A bungee cord wrapped around the cooler and posts on the mounting plate holds the cooler in place.

Some initial testing showed that the vehicle moved too fast even in low gear and tended to tip over, as you can see in the first video below. Some practice helped but a 3:1 reduction planetary gearbox brought the vehicle down to walking speed, making a big difference. A trip was arranged to go to local strawberry picking field at Red Fire Farms, but not without some excitement first. At 1AM the UNIK 320A High Voltage Speed controller emitted some magic smoke. A quick check with a thermal-camera found the culprit, one of the MOSFETs had failed, and after swapping it with one that was close enough they were back in business.

As you can see in the second video below, testing in the strawberry field went very well, though it wasn’t without some tipping. Kids also found it a fun diversion from picking strawberries, alternating between mock fright and delight.

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Hackaday Prize Entry: Selfie Bot Let’s You Vlog Hands Free

July 8, 2016 by Gerrit Coetzee 23 Comments

[Sergey Mironov] sent in his SelfieBot project. His company, Endurance Robots, sells a commercial version of the bot, which leads us to believe that in a strange and maybe brilliant move he decided to just sell the prototype stage of the product development as a kit. Since he also gave away the firmware, STLs, BOM, and made a guide so anyone can build it, we’re not complaining.

The bot is simple enough. Nicely housed hobby servos in a 3D printed case take care of the pan and tilt of the camera. The base of the bot encloses the electronics, which are an Arduino nano, a Bluetooth module, and the support electronics for power and motor driving.

To perform the face tracking, the build assumes you have a second phone. This is silly, but isn’t so unreasonable. Most people who’ve had a smart phone for a few years have a spare one living in a drawer as back-up. One phone runs the face tracking software and points the bot, via Bluetooth, towards the user. The other phone records the video.

The bot is pretty jumpy in the example video, but this can be taken care of with better motors. For a proof-of-concept, it works. A video of it in action after the break.

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Tissue-Engineered Soft Robot Swims Like A Stingray

July 7, 2016 by Dan Maloney 46 Comments

We’re about to enter a new age in robotics. Forget the servos, the microcontrollers, the H-bridges and the steppers. Start thinking in terms of optogenetically engineered myocytes, microfabricated gold endoskeletons, and hydrodynamically optimized elastomeric skins, because all of these have now come together in a tissue-engineered swimming robotic stingray that pushes the boundary between machine and life.

In a paper in Science, [Kevin Kit Parker] and his team at the fantastically named Wyss Institute for Biologically Inspired Engineering describe the achievement. It turns out that the batoid fishes like skates and rays have a pretty good handle on how to propel themselves in water with minimal musculoskeletal and neurological requirements, and so they’re great model organisms for a tissue engineered robot.

The body is a laminate of silicone rubber and a collection of 200,000 rat heart muscle cells. The cardiomyocytes provide the contractile force, and the pattern in which they are applied to the 1/2″ (1.25cm) body allows for the familiar undulating motion of a stingray’s wings. A gold endoskeleton with enough stiffness to act as a spring is used to counter the contraction of the muscle fibers and reset the system for another wave. Very clever stuff, but perhaps the coolest bit is that the muscle cells are genetically engineered to be photosensitive, making the robofish controllable with pulses of light. Check out the video below to see the robot swimming through an obstacle course.

This is obviously far from a finished product, but the possibilities are limitless with this level of engineering, especially with a system that draws energy from its environment like this one does. Just think about what could be accomplished if a microcontroller could be included in that gold skeleton.

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A Pi Robot Without A Hat

July 6, 2016 by Rud Merriam 10 Comments

Daughter boards for microcontroller systems, whether they are shields, hats, feathers, capes, or whatever, are a convenient way to add sensors and controllers. Well, most of the time they are until challenges arise trying to stack multiple boards. Then you find the board you want to be mid-stack doesn’t have stackable headers, the top LCD board blocks the RF from a lower board, and extra headers are needed to provide clearance for the cabling to the servos, motors, and inputs. Then you find some boards try to use the pins for different purposes. Software gets into the act when support libraries want to use the same timer or other resources for different purposes. It can become a mess.

The alternative is to unstack the stack and use external boards. I took this approach in 2013 for a robotics competition. The computer on the robots was an ITX system which precluded using daughter boards, and USB ports were my interface of choice. I used a servo controller and two motor controllers from Pololu. They are still available and I’m using them on a rebuild, this time using the Raspberry Pi as the brain. USB isn’t the only option, though. A quick search found boards at Adafruit, Robotshop, and Sparkfun that use I²C.

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Hackaday Prize Entry: Dtto Modular Robot

July 3, 2016 by Moritz Walter 16 Comments

A robot to explore the unknown and automate tomorrow’s tasks and the ones after them needs to be extremely versatile. Ideally, it was capable of being any size, any shape, and any functionality, shapeless like water, flexible and smart. For his Hackaday Prize entry, [Alberto] is building such a modular, self-reconfiguring robot: Dtto.

To achieve the highest possible reconfigurability, [Alberto’s] robot is designed to be the building block of a larger, mechanical organism. Inspired by the similar MTRAN III, individual robots feature two actuated hinges that give them flexibility and the ability to move on their own. A coupling mechanism on both ends of the robot allows the little crawlers to self-assemble in various configurations and carry out complex tasks together. They can chain together to form a snake, turn into a wheel and even become four (or more) legged walkers. With six coupling faces on each robot, that allow for connections in four orientations, virtually any topology is possible.

Each robot contains two strong servos for the hinges and three smaller ones for the coupling mechanism. Alignment magnets help the robots to index against each other before a latch locks them in place. The clever mechanism doubles as an ejector, so connections can be undone against the force of the alignment magnets. Most of the electronics, including an Arduino Nano, a Bluetooth and a NRF24L01+ module, are densely mounted inside one end of the robot, while the other end can be used to add additional features, such as a camera module, an accelerometer and more. The following video shows four Dtto robots in a snake configuration crawling through a tube.

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SpotMini Struts Its Stuff

July 1, 2016 by James Hobson 17 Comments

Boston Dynamics, the lauded robotics company famed for its ‘Big Dog’ robot and other machines which push mechanical dexterity to impressive limits have produced a smaller version of their ‘Spot’ robot dubbed ‘SpotMini’.

A lightweight at 55-65 lbs, this quiet, all-electric robot lasts 90 minutes on a full charge and boasts partial autonomy — notably in navigation thanks to proprioception sensors in the limbs. SpotMini’s most striking features are its sleek new profile and manipulator arm, showing off this huge upgrade by loading a glass into a dishwasher and taking out some recycling.

Robots are prone to failure, however, so it’s good to know that our future overlords are just as susceptible to slipping on banana peels as we humans are.

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Wireless Robotic Gripper With Haptic Feedback

June 29, 2016 by Gerrit Coetzee 17 Comments

We’re not sure what kind of, “High School,” [Sam Baumgarten] and [Graham Hughes] go to that gave them the tools to execute their robotic gripper so well. We do know that it was not like ours. Apparently some high schools have SLS 3D printers and Solidworks. Rather than a grumpy shop teacher with three fingers who, despite that, kept taking the safety off the table saws and taught drafting on boards with so many phalluses and names carved into the linoleum, half the challenge was not transferring them to the line work.

Our bitterness aside, [Sam] and [Graham] built a pretty dang impressive robotic gripper. In fact, after stalking [Sam]’s linkedin to figure out if he was the teacher or the student, (student) we decided they’re bright enough they could probably have built it out of scraps in a cave. Just like [HomoFaciens], and Ironman.

The gripper itself is three large hobby servos joined to the fingers with a linkage, all 3D printed. The mechanical fingers have force sensors at the contact points and the control glove has tiny vibrating motors at the fingertips. When the force of the grip goes up the motors vibrate more strongly, providing useful feedback. In the video below you can see them performing quite a bunch of fairly fine motor skills with the gripper.

The gripper is mounted on a pole with some abrasive tape, the kind found on skateboard decks. At the back of the pole, the electronics and batteries live inside a project box. This provides a counterbalance to the weight of the hand.

The control glove has flexible resistors on the backs of the fingers. The signal from these are processed by an Arduino which transmits to its partner arduino in the gipper via an Xbee module.

[Sam] and [Graham] did a great job. They worked through all the design stages seen in professional work today. Starting with a napkin sketch they moved onto digital prototyping and finally ended up with an assembly that worked as planned. A video after the break explaining how it works along with a demo video.

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