This project is aimed at creating a simple rover robot which can use a camera to identify navigational cues and interesting features when negotiating a maze.
The project consists of a) a set of CAD files used for fabricating the robot's chasis, and b) source code for motion control, vision, remote operation, and autonomous navigation.
- 4 8"x0.75" aluminum right angle extrusion
- 8 4"x0.75" aluminum right angle extrusion
- 84 M2.5 x 10 Socket head cap screws
- 8 M2.5 x 20 Socket head cap screws
- 92 M2.5 Nuts
- 1 PandaBoard, with SD card
- 1 Arduino
- 2 Continuous rotation servos
- 2 P1230 Photogates & supporting hardware (refer to your photogate's datasheet.)
- 1 USB webcam (I used a V7 CS2021.)
- 3D printer (I recommend using FDM'd ABS for this for its mechanical qualities.)
- Drill press
- Soldering iron
- Tweezers (highly recommended for both soldering and tightening fasteners.)
Ok, so you want to build your own robot. How do you get started?
First, you're going to need a chasis. There's no reason you have to use mine versus building your own, but in case you do, all the files you need should be in the draw/ directory. All of the parts except for angle aluminum and fasteners are available as .stl meshes, ready and tested for 3D printing. Most are also provided as STEP files that can be imported into all major CAD systems and modified to suit your needs. You'll also need to cut and drill some pieces of angle aluminum to serve as the primary structural members. I've included drawings of these parts to give you the right dimensions. All of it goes together as an assembly as detailed in the assembly.pdf drawing.
Great, you have a chassis to hold everything in place. Now you're going to need some electronics to drive it! The "ServoBracket.{step, stl}" parts are designed to hold a standard size servo. Of course, a standard servo won't work for turning wheels; you'll need continuous rotation ones. Mount two of them in the brackets. In order to keep track of distance traveled and current speed settings, you'll need to have some kind of encoder on your wheels. I designed a 3D-printable encoder wheel that sits between the servo and the drive wheel. It's designed to fit into a P1230 photogate, though it should fit others as well. These can be slotted into the smaller holes on the servo bracket and glued into place with a 2-part epoxy. Connect the servos and photogates to an Arduino, modify the firmware to match your pin choices, and upload the firmware. Congrats, you have a simple motion control system!
Next comes the brains of the operation. I assume that you made 3 of the board mount assemblies; if not, do so now. These have little arms that rotate to meet up with holes in the PandaBoard. Mount your board in the most convenient orientation; I decided to put the USB ports forward. Attach the Arduino via USB to the board, and do the same for your webcam. There is a part for mounting a V7 webcam to the chasis; if you have a similar device it should work well, and if not you'll have to design your own. Attach your webcam to the chasis.
All right, that just about covers the hardware! Next step, software.
I'll assume that you have a working Linux distribution on your PandaBoard. You're going to need to install Python (2.7 is preferred), OpenCV and its Python bindings, PySerial, and Git. Clone this repo onto the PandaBoard, check that settings.py reflects your configuration, and start up BotDriver. It will attach to the network interface and wait for a connection from Pilot. On your control machine, start a Processing session and initiate a Pilot run. Enter the IP address of the robot and hit "Connect". If everything's working, it should start feeding you video and relaying your commands to the robot. If not, something went wrong; look at the output of both Pilot and BotDriver to see if either of them has any useful information. If not, feel free to get in contact with me.
I'm open to incorporating updates or changes to any of this software/hardware; if you make any improvements, I'd love to hear about them! If they have any chance of being useful for other people, send me a pull request and I'll try and merge them.
See the issue tracker.
All of the code in this repository is free software, licensed under the GNU GPL. If you'd like an alternative license, contact me and we'll work something out.