I have two basic starting points; the first is to test the feasibility of tin cans as a structural medium. The second is the issue of control.
The tin can structure
The current idea is to segment the tins, making tubular sections that contain functional modules. Theses tubes will have an inner-lining wall which can be used to mount boards and components, as well as making the sections stack. The top section of the can robot (which may be a underside peice) will house a few staple senosrs, some LEDs or other generic audio-visual components and then the micro-controller. At this point, that`s an Arduino Pro Mini. In contrast, the bottom may house motors for locomotion and batteries, maintaining a low centre of gravity.
Having chopped up a few tin cans, my intial findings are listed below as pros and cons:
- Cans are easy to cut and drill.
- Cheap material that is readily available.
- Compatible with chemical welding.
- Accurate cutting with a good finish is difficult.
- No flat surfaces for mounting components.
- Inner surface difficult to insulate effectively (shorting risk).
- Metal warps and tears easily which interferes with stacking.
The challenge to make this work will be a way of easily assuring a workable structure. I may need to make a separate sub-structure that the can and components may be mounted to, rather than relying solely on the can`s own rigidity. An alternative may be to keep the set height form factor and make front slot-in modules.
The hope behind the modules is that you get plug-and-play functional parts of the robot that you can easily swap out, such as a grabber, or a distance measurer. To make this easy, each module should have an integrated degree of operational self-autonomy. For example, if you attach a grabber, it should be able to open and close itself, and know when it achieves the required state. I`ll be short of space in the can, so for this, I`m going to use an ATtiny45 chip in each module. In the next post, I`ll start to look at making the chip communicate with my Arduino.