Remote-controlled Tank Tread Robot Will Walk The Dog For You

March 22, 2011 by Mike Nathan 30 Comments

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Instructables user [IAMTHEBOT] recently finished building his robot which can be controlled by a human using an R/C transmitter, via a PC, or through its built-in object avoidance system. The robot doesn’t seem to have a name, though Johnny Five might be appropriate.

The robot was built using plenty of erector set parts, as well as a Lynx motion tank tread kit. The robot is crammed full of controllers, including a Propeller USB servo controller which operates the arms, and a pair of Parallax motor controllers to manage the tread movement. A pair of Parallax Stamp controllers are used to drive these controllers as well as to manage the remainder of the robot’s functions.

The robot’s head consists of a custom pan and tilt wireless camera system, which allows him to drive it around from the comfort of his home, while watching the video stream on his PC. The robot also has the ability to roam around autonomously, avoiding objects using a ping sensor that can be mounted where the camera is currently located. It seems all that’s missing is Steve Guttenberg.

As you can see in the videos below, the robot manages pretty well on all sorts of surfaces, and even walks this guy’s dogs.

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Freedombot Explores Your Fridge

March 21, 2011 by Chris Nelson 10 Comments

Freedombot is a neat little robot designed for exploring magnetic surfaces. It has two whiskers for detecting objects in its path and two rare earth magnets which allow it to stick to your fridge.

Overall Freedombot may not be anything revolutionary but its builder [skater_j10] does a good job of covering topics which my be interesting to robotics beginners. For example he goes through the process of modifying some HiTec HS- 55 Micro Servos for continuous rotation which allows them to act as the wheels. To control the bot he uses two 555 timers wired up in astable mode to generate the needed PWM for the servos. The proximity sensors are simple limit switches with some wire soldered on to the end. The end result is a neat little robot for roaming the front of your fridge. See a video of it in action after the break.

This happens to be [skater_j10]’s entry into the 555 timer contest. Unfortunately the deadline has passed for new entries but be sure to swing by and check out some more awesome 555 hacking.

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Simple Robot Knows Its Bounds

March 21, 2011 by Mike Nathan 8 Comments

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The [Dallas Personal Robotics Group] recently put together a set of tutorials for their members, including the build process of a table-top robot, they call the Tiny Wanderer. The bot can be constructed pretty easily, and is meant as an introduction to robot building.

The small servo-driven bot uses simple edge sensors to ensure that it doesn’t fall off a raised surface. The sensors were built using a small IR LED and photo transistor, which is partially isolated from the LED by a piece of shrink tubing. An ATiny micro-controller takes two measurements of the amount of IR light entering the photo transistor – one with the LED on, the other with the LED off. The difference of these measurements is compared to determine if the edge sensors are hanging off the side of the table. The logic used here is pretty simple – the difference will be high if the sensors are hovering over a surface, due to reflected light, and low if the sensors are hanging over open space.

The writeup contains templates for building the bot’s structure, as well as source code and schematics for all of the electronic bits.

Be sure to stick around to see a video of the robot in action.

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Tricycle Robot Using Omni-wheels

March 21, 2011 by Mike Szczys 10 Comments

[Markus Gritsch] built this six-wheeled robot using omni-wheels. Two wheels are used on each axis in order to ensure perpendicular rotation is possible no matter where the axis rotation stops. The wheels have also been improved by dipping the elliptical components to give them a rubbery coating.

The robot gets its commands wirelessly from a separate controller unit. That controller, as well as the bot seen above, uses a Teensy microcontroller board. Two analog sticks take input from the operator and transmit commands using an inexpensive RF pair. The wheel movement is facilitated by three servo motors which may seem like an odd choice. But we think that it simplifies the electronic side of the build because you do not need an H-bridge to control a servo motors. It’s a bit loud, as you can hear in the video after the break, but it certainly works quite well.

One of the commenters on the thread above asks why [Markus] didn’t use mechanum wheels. These would have allowed him to use just one wheel on each axis but the omni-wheels were so inexpensive that he went this route instead.

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Robot Gets Around On Lopsided Wheels

March 18, 2011 by Mike Szczys 16 Comments

This concept robot uses angular momentum to roll around. You can see that on either end of the robot there are two discs which have been cut on one side to make them off-balance. For locomotion, two DC motors spin the outer discs which are not in contact with the floor. This spinning action exerts a force in the opposite direction on the body of the vehicle, causing it to move.

It’s not a perfect system and there is one major flaw with using this system. When the forces have equalized acceleration will stop and it will eventually come to a standstill. You can’t just stop spinning the motors because that will act as a braking mechanism. But still, it’s a concept we haven’t seen before and we love the experimentation that’s happening here. Take a look at the test footage after the break and don’t hesitate to let us know if this starts causing light bulbs to flip on above your head.

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Bristlebot Mod Never Rubs You The Wrong Way

March 13, 2011 by Mike Nathan 6 Comments

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[Underling] sent in his bristlebot project that aims to put a new spin on controlling bristlebot movement. We have seen several attempts at bristlebot directional control in the past, but none of these methods really fit what he wanted to do. His goal was to use a single brush rather than two, and be able to aim the bot in any direction at will.

He tried several different designs, but settled on what you see in the picture above. The large brush head is fitted with a vibrating motor on the front as well as a cell phone battery near the midsection. These pieces are placed in the center plane of the brush as to not influence the direction of movement. A separate servo-like motor is placed on the back of the brush, and each side of the motor’s arm is attached to a paddle that extends down the sides of the brush. When the motor is activated, one paddle is pressed in towards the bristles, while the other paddle is pulled away. This causes an immediate shift in direction, and should provide for a relatively tight turn radius. It should be noted that he also took the time to remove bristles from the center of the brush where the steering paddles are located in order to improve turning performance.

Unfortunately [Underling] does not currently have a video camera with which to show off his work, but we hope to see some action footage in the near future.

Protei: Articulated, Backward Sailing Robots Clean Oil Spills

March 12, 2011 by Mike Szczys 15 Comments

The Protei project aims to develop a robotic solution for oil-spill cleanup. [Cesar Harada] quit what he calls his dream job at MIT to work toward a solution to the ecological disasters that are oil spills. He had previously been working on Seaswarm, a swarm of robots that use conveyor belts of absorbent material to leech oil from seawater. But Protei doesn’t use legions of drones. It aims to use better design to improve the effectiveness of a small number of units.

The whole idea is well described in the video after the break. If a long trailing boom of absorbent material is towed in a serpentine pattern perpendicular to the flow, starting down current and moving upward, it can be quite effective at halting the spread of crude. Initial experiments have shown that a robotic vessel can do this efficiently with just a few improvements. First, to counteract the drag of the tail the rudder of the boat was moved to the bow. Secondly, the hull has been articulated as you can see above. This allows the robot to better utilize wind power to sail, making turns without losing the push of the wind.

The project is raising money through Kickstart as an open hardware project. Let’s hope this becomes a cheap and effective way to fix our costly drilling mishaps. Continue reading “Protei: Articulated, Backward Sailing Robots Clean Oil Spills” →