I am building a planar RR arm to be used for drawing. The arm will use two servos for joint control and be made of predominantly polycarbonate. At the end effector is a pen holder which will allow the robot to grasp a pen. The robot will create continuous line drawings based on images that are converted into path files. Below are some additional images of the arm design including my concept sketches.
I built a frame that paint bot can be mounted on for testing. I built it out of scrap lumber from the CMU Robotics Club. The frame has the motors mounted near the top with the cables running through guides at the top of the frame.
I currently do not have any sort of painting mechanism mounted to paint bot. I’m thinking about building a marker holder so I can test it a little easier than using spray paint. Currently I just have a weight attached to the two cables to simulate the painting mechanism.
I completed the main electronics board for Paint Bot in Mid-July. The control board consists of an Arduino Microcontroller, a motor driver from Pololu and a custom circuit board (perf board) that does some interfacing for the sensors. The board is mounted on a piece of 3mm acrylic.
Over the past month or so I have been working on building a painting robot. This robot will be able to paint a wall using spray paint in a graffiti-esque manner. My initial inspiration, and thus similarity in design, was a robot called Hektor. Hektor was a graffiti robot built as a project by Jürg Lehni with help from Uli Franke at écal, the University of Art and Design Lausanne. More about Hektor here and écal here.
I just finished some testing on my spray paint can holding/spraying mechanism. The video below shows the second test of the spraying mechanism. In the initial setup the servo used to depress the spray nozzle couldn’t provide enough downward force all the time. The second video shows an attempt at getting around this issue by the servo pressing on the nozzle from a different direction.
Second Spray Test:
Initial Spray Test:
I will probably end up modifying the spraying mechanism further so it is less of a hack to get it to depress the spray can nozzle.
The following pictures show the can holder and spraying mechanism during the build:
I’ve also finished building motors to move the spray can around. When I get time, I’ll post something about the motor build.
During the previous semester, as part of a class project, we built urban search and rescue robots. We built the robots using the LEGO NXT set. For our robot I built a custom pan-tilt mechanism to mount the camera we were provided with.
The pan-tilt used two servos and a custom microntroller board to interface the servos with the NXT. The controller board also allowed for LEDs (used for illumination) to be turned on and off.
We controlled the robot over a bluetooth link via joystick. It turns out that the NXT brick times out after 15 min no activity and that an open bluetooth does not count as activity.
In short, this project ruined my childhood and made me hate LEGOs. The constraints of the project made it very difficult to build an effective robot. However, a simple combination of wheels and treads let a build a robot to fit the constraints.
We’ve mounted Stairbot in a hanging position so we could perform some testing on its legs. We’ve discovered some issues with our servos, and we keep blowing some of them up. We’re not sure if it’s an issue with the design, or if the servos are bad.
A video of the legs cycling through some motions:
We also have some pictures of the hanging setup:
My Mobot for the 2010 Mobot race has finally been completed. I have tested it electrically, so I know that part works (all of the sensors!). I’m working on writing code for the race (just over a week away!). I’ll add more pictures and talk about progress as it’s made. Hopefully I’ll get some video of it in action!
Stairbot is getting closer and closer to completion. The above render is what the final version should look like. We’ve decided to laser cut a lot of acrylic to build most of the leg and body structure.
We’ve ordered all of our electronics, and we should be receiving them soon. Then we can start actually programming and getting gaits set up. Our goal is to have the construction mostly completed by the end of the month, and start working on some basic motion control.
Below are some images from the build process.
I managed to get a gallery of a step-by-step build of the MicroColony/Build18 sensor board uploaded. This post details the sensor board itself a bit better.
We plan on building a better one that uses a multiplexor to allow us to have more than 5 sensors on the board.
During Build 18 I managed to slap together a simply chassis for our micro colony robots. It was super simple, made of some plastic and hot glue, but, it was able to hold everything on it.
Here are some pictures:
As you can see it isn’t very big, not much larger than my cell phone. I used 3 4-40 machine screws which let us slide the sensor board into place and tuck all of the electronics underneath. I really like the 4-40 screws for stacking feature and it is something I would like to retain for the next revision of our chassis.
The next revision will also have a mount for the servos, instead of them just being tacked in place with hot glue. It was a quick and dirty build, but, it got the job done.