Giving Control Of A Smartphone Robot To A Raspberry Pi

July 21, 2021 by 3 Comments

Most gadgets that interface with smartphones have a rather short lifespan and inevitably end up as E-waste. Unless hackers give them a second life, as is the case with the Romo, a little smartphone-controlled robot. [David Goeken] has successfully reverse-engineered the communication protocol to allow the Romo to controlled Raspberry Pi (or microcontroller)

The Romo was a little iPhone-controlled robot brought to market with a Kickstarter campaign back in 2013. It originally used the audio jack from the iPhone for the control interface, but was quickly followed by an updated version that used iPhone 4’s 30 pin connector and later the Lightning port. Romotive, the company behind Romo, eventually went out of business, but fortunately, they open-sourced the IOS app and the firmware. This has led to a few third-party apps currently on the app store.

[David] wanted to use other hardware for control, so he set about reverse-engineering the protocol using the open-source software and a logic analyzer. Unsurprisingly, it uses a serial interface to send and receive commands, with two additional pins to detect the connection and wake up the Romo. After breaking out the interface header on the board, he was able to modify the Romo to mount a Raspberry Pi Zero, and power it using the internal battery.

[David] has not made his code public yet, but it sounds like he plans to. It looks like Romo’s can be a fun little experimentation platform, and they can be found for cheap on eBay. We covered another cool Romo hack back in 2014, which used a projector and vision system to create a Mariokart-like game.  For a completely open-source smartphone robot, check out the OpenBot.

A Capable Nerf Launcher Robot

July 12, 2021 by 5 Comments

Nerf blasters are fun to play with, and it’s now possible to even get robotic Nerf launchers you can use to chase around your friends. [Engineering After Hours] wasn’t satisfied with the official hardware, though, so built his own remote control Nerf rig to battle it out in the back yard.

The rig is built around an earlier build from [Engineering After Hours], a skid-steer RC chassis that is nice and tough to handle rough and tumble driving. It’s paired with a trailer attached to the center of rotation of the chassis that makes the pair highly maneuverable.

In order to launch rockets, an air tank on the trailer is hooked up to some piping to launch four Nerf rockets. Charged up to just 40 psi, it’s capable of launching the rounds with plenty of power for play purposes. Paired with a elevation control and a servo to trigger the firing valve, it’s a complete system that can shoot on the go.

It’s a fun build that packs a punch, even if it doesn’t quite have the accuracy or range you might desire in an all-conquering Nerf combat platform.  We’d love to see a similar build hooked up to some AI smarts to stalk targets independently of human control. Video after the break.

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Hackaday Podcast 126: Cable 3D-Scanner, Tesla Charger Robot, Ultrasonic Anemometer, And A Zoetrope

July 9, 2021 by No comments

Hackaday editors Elliot Williams and Mike Szczys dive into a week of exceptional hacks. Tip-top of the list has to be the precision measuring instrument that uses a cable spooling mechanism. There’s news that the Starlink base station firmware has been dumped and includes interesting things like geofencing for the developer modes. We saw a garage robot that will plug in your electric vehicle if you’re the forgetful sort. And we close up by talking about heavier-than-air helium airships and China’s Mars rover.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (55 MB or so.)

Places to follow Hackaday podcasts:

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This Horrifying Robot Is Here To Teach You A Lesson

July 1, 2021 by 8 Comments

No, despite what it might look like, this isn’t some early Halloween project. The creepy creation before you is actually a tongue-in-cheek “robot” created by the prolific [Nick Bild], a topical statement about companies asking their remote workers to come back into the office now that COVID-19 restrictions are being lifted. Why commute every day when this ultra realistic avatar can sit in for you?

OK, so maybe it’s not the most impressive humanoid creation to ever grace the pages of Hackaday. But if you’re looking to spin up a simple telepresence system, you could do worse than browsing through the Python source code [Nick] has provided. Using a Raspberry Pi 4, a webcam, and a microphone, his client-server architecture combines everything the bot sees and hears into a simple page that can be remotely accessed with a web browser.

Naturally this work from home (WFH) bot wouldn’t be much good if it was just a one-way street, so [Nick] has also added a loudspeaker that replays whatever he says on the client side. To prevent a feedback loop, his software includes a function that toggles which direction the audio stream goes in by passing the appropriate commands to the bot over SSH; a neat trick to keep in mind for your own, less nightmarish, creations.

If you’re looking for something a bit more capable and have some cardboard laying around, this DIY telepresence mount for your phone might be a good place to start.

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Machine-Vision Archer Makes You The Target, If You Dare

June 30, 2021 by 6 Comments

We’ll state right up front that it’s a really, really bad idea to let a robotic archer shoot an apple off of your head. You absolutely should not repeat what you’ll see in the video below, and if you do, the results are all on you.

That said, [Kamal Carter]’s build is pretty darn cool. He wisely chose to use just about the weakest bows you can get, the kind with strings that are basically big, floppy elastic bands that shoot arrows with suction-cup tips and are so harmless that they’re intended for children to play with and you just know they’re going to shoot each other the minute you turn your back no matter what you told them. Target acquisition is the job of an Intel RealSense depth camera, which was used to find targets and calculate the distance to them. An aluminum extrusion frame holds the bow and adjusts its elevation, while a long leadscrew and a servo draw and release the string.

With the running gear sorted, [Kamal] turned to high school physics for calculations such as the spring constant of the bow to determine the arrow’s initial velocity, and the ballistics formula to determine the angle needed to hit the target. And hit it he does — mostly. We’re actually surprised how many on-target shots he got. And yes, he did eventually get it to pull a [William Tell] apple trick — although we couldn’t help but notice from his, ahem, hand posture that he wasn’t exactly filled with self-confidence about where the arrow would end up.

[Kamal] says he drew inspiration both from [Mark Rober]’s dart-catching dartboard and [Shane Wighton]’s self-dunking basketball hoop for this build. We’d say his results put in him good standing with the skill-optional sports community.

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Robotic Ball-Bouncing Platform Learns New Tricks

June 30, 2021 by 11 Comments

[T-Kuhn]’s Octo-Bouncer platform has learned some new tricks since we saw it last. If you haven’t seen it before, this device uses computer vision from a camera mounted underneath its thick, clear acrylic platform to track a ball in 3D space, and make the necessary (and minute) adjustments needed to control the ball’s movements with a robotic platform in real time.

We loved the Octo-Bouncer’s mesmerizing action when we saw it last, and it’s only gotten better. Not only is there a whole new custom ball detection algorithm that [T-Kuhn] explains in detail, there are also now visualizations of both the ball’s position as well as the plate movements. There’s still one small mystery, however. Every now and again, [T-Kuhn] says that the ball will bounce in an unexpected direction. It doesn’t seem to be a bug related to the platform itself, but [T-Kuhn] has a suspicion. Since contact between the ball and platform is where all the control comes from, and the ball and platform touch only very little during a bounce, it’s possible that bits of dust (or perhaps even tiny imperfections on the ball’s surface itself) might be to blame. Regardless, it doesn’t detract from the device’s mesmerizing performance.

Design files and source code are available on the project’s GitHub repository for those who’d like a closer look. It’s pretty trippy watching the demonstration video because there is so much going on at once; you can check it out just below the page break.

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Ball CVT Drives Robot From A Constant Speed Motor

June 29, 2021 by 13 Comments

[James Bruton] is experimenting is a series of interesting mechanical mechanisms, the latest being a CVT transmission system which uses a tilting sphere to get a variable speed output from a constant speed input. Video after the break.

In [James]’ proof of concept RC vehicle, a single powered disc is mounted on top, at 90 degree to the wheels. A rotating sphere makes contact with both the driven disc and the wheel. When the rotation axis of the sphere is at 45° between the disc and the wheel, it provides a one 1:1 transmission ratio. As the axis is tilted, the contact points on the sphere shift, changing the relative circumference at the contact points, and therefore changing the transmission ratio. It can also reverse by tilting the sphere in the opposite direction, and disconnected from the output wheel by aligning it with the hole in the bottom of the sphere. [James]’ simple two-wheel RC car concept quite well, driving around his kitchen with the transmission spheres being tilted by servos.

Thanks to the response time, CVT gearboxes are generally not needed for electric motors, but on internal combustion engines that which run best within a certain RPM range they can be very useful. One possible weak point of a design like this is it’s dependence on friction to transfer torque, which makes it vulnerable to wear and slipping.

This build is a spin-off of his spherical omni-wheels and the robot chassis he developed around them. For another interesting robot mechanism, check out is gyroscope balancing system. Continue reading “Ball CVT Drives Robot From A Constant Speed Motor” →