0.19 Leagues Under The Sea

ROV

[Doug] and [Kay] have been building a steel 70-foot sailboat for the last few years, and since it’s a little too cold to work outside their home/shop in Oklahoma, they’re bringing their projects inside for the winter. Until it warms up a bit, they’re working on an underwater ROV capable of diving to 3000 feet below the waves, maneuvering on the ocean floor, and sending video and side-scan sonar back to their homebuilt ship.

Like [Doug] and [Kay]’s adventures in shipbuilding, they’re documenting the entire build process of ROV construction via YouTube videos. The first video covers the construction of a pressure vessel out of a huge piece of 10″ ID, half inch wall steel pipe. The design of the ROV will look somewhat like a torpedo, towed by the ship with cameras pointing in all directions.

For communication with the surface everything is passing over a single Cat5 cable. They’re using an Ethernet extender that uses a twisted wire pair to bring Ethernet to the ocean bottom. With that, a few IP webcams relay video up to the ship and a simple Arduino setup allows for control of the ships thrusters.

The thrusters? Instead of an expensive custom solution they’re using off the shelf brushless motors for RC cars and planes. By potting the coils of a brushless outrunner motor, [Doug] and [Kay] found this solution makes an awful lot of sense; it’s cheap, fairly reliable, doesn’t require a whole lot of engineering, and most importantly cheap.

Bunch of videos below, or just check out [Doug] and [Kay]’s progress on their slightly out-of-date blog.

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PIDDYBOT – A Self Balancing Teaching Tool

We’re sure that most Hackaday readers are already familiar with the inverted pendulum system, which basically consists of a pendulum having its center of mass above its pivot point. Most applications (like the one we are going to describe) limit the pendulum to 1 degree of freedom by affixing the pole (or circuit board here) to an axis of rotation. The overall system is therefore inherently unstable and must be actively balanced in order to remain upright.

[Sean] created the piddybot, a tiny balancing robot aimed to teach the basics of PID control by trying to get the robot to stand still. More interestingly, the Proportional / Integral / Derivative values can directly be adjusted using the three on-board potentiometers. This will allow users to get the feel of each parameter’s impact on the robot behavior. The piddybot is based around the Arduino nano, a custom PCB, 2x 26:1 geared motors, one 1A dual motor driver board, a six degrees of freedom Inertial Measurement Unit, 2 batteries and finally a 3D printed body. You can check out a video of the robot in action after the break.

This project stems from a non-PID self balancer which [Sean] hacked together in September.

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Miniscule Line-Follower

miniscule-line-follower

Building line following robots is fun and easy. Building a line-follower that is this tiny is a different story. The surprising thing for us is that despite how it looks, this robot whose name is Rizeh doesn’t use wheels to get around. [Naghi Sotoudeh] built the line-follower using two vibrating motors, with needles (not shown above) making three points of contact with the ground.

His website is a little sparse, but hit the downloads page to get a PDF file that serves as the build log. We also downloaded the 32 second demo video which is worth it. The magic-marker track that the bot is circumnavigating isn’t any bigger than the palm of your hand!

Onboard the diy PCB you’ll find two GP2S04 IR reflectance sensors which detect the black line on a white paper. The power-up sequence spends a few seconds calibrating these sensors. Speaking of power, [Naghi] went with a lithium polymer cell from a Bluetooth headset. At the heart of it all is an ATtiny45 which uses its hardware PWM capabilities to drive the two motors.

Of course line-followers rank up there with self-balancers as our favorite robot projects. But by far the ones we love the most are the speed-run maze solvers.

R/C Rock Crawler Prepped To Become Stair Climbing Robot

rc-robot-frame

[Starlino] is working on an autonomous mobile robot. Like many before him, he looked to the radio controlled car world for a base frame. He found a good candidate in a rock crawler model called “Mad Torque”. Crawlers have been around for years, but they’ve recently been getting more popular. As always, popularity leads to lower priced entry-level models, which puts this crawler at a reasonable price for a robot frame. As the name implies, rock crawlers are all about crawling. Relatively low speeds, locked differentials, four-wheel drive, and (optional) four-wheel steering.

Of course, [Starlino] had to test drive his frame out before tearing it down to install electronics. As long time R/C modelers ourselves, we can’t blame him. Testing uncovered one major problem. The Mad Torque wasn’t quite mad enough to climb the stairs in his house. The front tires would grab and pull over the first step, but the wheelbase wasn’t quite long enough for the rear wheels to grab hold.

[Starlino’s] solution was to extend the wheelbase. For most 4WD R/C cars or trucks this would be a major problem, as the motors are mounted amidships. An extended wheelbase would mean also extending the drive shafts or belts. This isn’t a problem with rock crawlers. Crawlers need to support huge amounts of suspension articulation. Rather than create complex drive linkages, the common design is to place an electric motor on each axle. This isn’t the greatest idea in terms of unsprung mass, but it does make for easy wheelbase changes. [Starlino] found that the design was so modular he could bolt a second chassis up to the original. The new rear chassis bolted to the front at the top shock mounts. An extra set of battery brackets formed a lower brace. The new extended truck was long enough to clear the steps, though it does still struggle a bit, as can be seen in the video. We think larger diameter tires might help a bit here. [Starlino’s] next step is to ditch the R/C unit and give this ‘bot a brain!

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Autonomous Quadcopter Fits In The Palm Of Your Hand

[Horiken Engineering], which is made up of engineering students at the department of aerospace at the University of Tokyo have developed an autonomous quadcopter that requires no external control — and its tiny. By using two cameras and a sonar sensor, the quadcopter is capable of flying by itself due to its ability to process the data from the on-board sensors. To do the complex data processing fast enough to fly, it is using a Cortex-M4 MCU, a Spartan-6 FPGA, and 64MBs of DDRSDRAM. It also has the normal parts of a quadcopter, plus gyros, a 3D printed frame and a 3-axis compass. The following video demonstrates the quadcopter’s tracking ability above a static image (or a way point). The data you see in real-time is only the flight log, as the quadcopter receives no signal — it can only transmit data.

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Giving A Roomba Internet Connectivity

roombahack01_09

What was supposed to be a fun 1-day build ended up turning into a 3-day journey full of close calls when [Arthur] decided to give his Roomba Internet Connectivity.

The Roomba, whom [Arthur] calls Colin, has been in service for a couple of years, and once he got his hands on the Electric Imp, he had just the project in mind.  With embedded Wi-Fi and a 32-bit processor all in an SD Card form factor, the Electric Imp makes it very easy to add the “Internet of Things” to just about anything you can think of.  [Arthur] wanted to gain control of the Roomba, so he tapped into the SCI (Serial Command Interface).  Now he can read out the Roomba’s on-board sensor data including battery voltage, current draw, and even the temperature.

These are the kind of walk-through’s we love to see, because he did it in real-time, so you get to experience all of the “surprises” along the way.  For example, he removed an external charging port to make room for the added components, but that ended up disabling the dock charger.  Then he discovered that when the Roomba was charging, the input voltage to the Electric Imp breakout board was too high, so he had to introduce an intermediate voltage regulator.  But perhaps the biggest bump in the road was when he accidentally brushed the Electric Imp breakout board along the Roomba’s control board while power was on.  Luckily the damage was isolated to just one smoked — a simple FET.  The project turned out great, and (today) Colin’s data is actually visible through a public Xively feed.

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Rex, The ARM-Powered Robot Board

REX

There are a million tutorials out there for building a robot with an Arduino or Raspberry Pi, but they all suffer from the same problem: neither the ‘duino nor the Raspi are fully integrated solutions that put all the hardware – battery connectors, I/O ports, and everything else on the same board. That’s the problem Rex, an ARM-powered robot controller, solves.

The specs for Rex include a 1GHz ARM Cortex-A8 with a Video SoC and DSP core, 512 MB of RAM, USB host port, support for a camera module, and 3.5mm jacks for stereo in and out. On top of that, there’s I2C expansion ports for a servo adapter and an input and output for a 6-12 V battery. Basically, the Rex is something akin to the Beaglebone Black with the hardware optimized for a robotic control system.

Because shipping an ARM board without any software would be rather dull, the guys behind Rex came up with Alphalem OS, a Linux distro that includes scripts, sample programs, and an API for interaction with I2C devices. Of course Rex will also run other robotics operating systems and the usual Debian/Ubuntu/Whathaveu distros.

It’s an impressive bit of hardware, capable of speech recognition, and machine vision tasks with OpenCV. Combine this with a whole bunch of servos, and Rex can easily become the brains of a nightmarish hexapod robot that responds to your voice and follows you around the room.

You can pick up a Rex over on the Kickstarter with delivery due sometime this summer.