The principle behind this design is that the rover is a micro-rover, similar to the Sojourner.
>Has 6 wheels
>Is a very small and compact size but everything is housed within the body
>Camera is in fixed position
>Could also have a simulated ‘base unit’ on the terrain that users can drive onto and find out about
>However ground clearance would be comparatively low
This design is supposed to replicate the Nasa rovers and be a scaled-down version of the Spirit and Opportunity rovers.
>It has 6 wheels on long ‘legs’
>It has a camera mounted on a ‘neck’ that has the potential to be moveable
>It features a layer of solar panels on the top to cover the electronics from view
I first looked at existing rovers that have been created using the Raspberry Pi, and what electronic parts they used.
These two projects seemed to offer the most information:
It seems that I can either wire through a motor driver board, or simply use a breadboard and resistors.
Here is a diagram of the Raspberry Rover which uses a motor driver board (click to enlarge):
The board takes the signal from the GPIOs and controls the voltage directly so that there is no need for resistors. Both wheels on the same side are linked to the same set of 2 outputs. It is probable that this rover uses tank controls (to turn, wheels on one side reverse while on the other they continue forwards) as there is no servo to control the steering.
This is a diagram of the wiring on the Curiosity Pi (click to enlarge):
Instead of motors and a motor driver, this rover uses 16kohm and 180ohm resistors which are connected to servos. This controls steering, camera motion and the drive of a single front wheel. This method may be more complicated when more wheels need to be controlled.
I will need to combine multiple technologies to realise the project successfully.
The rover will require a chassis with wheels and motors to drive the wheels. These can be acquired in kits, or I can put one together myself. If I am replicating the current Mars rovers then I will need one with six wheels that are on elongated struts.
A touchscreen tablet device could be used to both control the rover, to view the video feed or both.
The Raspberry Pi will need an extraneous wireless power source that can be fitted to the rover with it. A rechargeable battery pack with a 5v output will work well for this.
The Pi will also need a webcam or the compatible camera module.
A wireless connection between the Pi and another device is necessary for control and to relay the video feed.
Alternate control devices:
Alternate video viewing devices
Chroma Keying ( sometimes known as greenscreen or bluescreen) could be used to show images or videos to the user through the same video feed as the camera. A narrative or other information about space or rovers or telepresence could be then implemented easily.
I have chosen to pursue the rover idea. This is due to the following criteria:
- Highly interactive
- Interesting combination of physical and virtual interaction
- Room to be creative
- Different solutions
- Can deliver information and be entertaining.
Here are some possibilities that I would like to explore moving forward from the initial idea.
- Setting the rover in a simulated landscape such as the Moon or Mars.
- Delivering information or narrative to the user, for example using pre-recorded videos that play at various points.
- Making the user feel as though they are controlling a rover on another planet.
A mock up of how the construction might look.
The rover could be placed on a simulated planet’s surface inside of a sandbox type construction, with the sides resembling the view from the planet.
The user could use a joystick, a touch-screen or a computer to control the rover.
The camera could move and be controlled separately.
This would use the camera functions and the GPIOs on the Raspberry Pi. The robotic arm would be controlled by the Pi in such a way that the user could choose an object, and then using the technology behind motion tracking, the arm would find and move the object to a new location. The possibility of voice commands could also be explored so that the only input device is the user’s voice. The technology could be useful in other applications, eg. assisting with mobility for those with disabilities.
The Raspberry Pi would control a rover or car with a camera on it that could travel around a space and look at different objects that create a story or give information on a particular subject. The user may not be able to see the rover, instead relying on the camera feed to see where they are going.
The Pi is the most useful tool for this for its GPIO pins that allow it to control things via electrical signals and its ability to support a camera and send the video feed over a wireless network, as well as its compact size letting it be mounted on a vehicle.