The purpose of this project was to design, construct and test a prototype implementation of a GPS interface for road cyclists, which may be used without their being distracted from the road surface. This is a combination of software and hardware which allows connections from existing smartphone applications to the device in order to allow them to display navigation directions when necessary. The motivation for this is to improve road safety whilst ensuring that the amount of information presented to cyclists is sufficient.
Examining the technological constraints of such a system, and why it has not been implemented in this way in the past, is important for this project, as is ensuring that all road regulations are complied with. A device such as this may require explicit approval before it can be used on public roads.
A fully-functional prototype of the hardware and software was developed and tested in order to test the usefulness of such a system.
The end result is a fully-functional implementation of the requirements with a number of extension plans implemented also. This can be tested and improved upon based on user experience and reviews.
The block diagram shows the rough implementation of the whole system. Most of the blocks should be self-explanatory, aside from:
The Safety Circuit - this looks at laser movements and switches the laser off if it's stationary for more than an appropriate timeout.
DAC - these are MCP4822 units, controlled over SPI
The arrow towards the power supply controls power to the galvonometers via relay. This is because they draw ~150W (closed loop).
This is why you're here. We all know it.
This shows the main blocks of the galvonometer setup.
Laser (Red) - This was replaced with a slightly stronger green unit in the final design.
Photodiode (Green) - This was part of the safety circuit. Laser must hit the photodiode before the timeout to avoid being shut off (this is to prevent it sticking)
This shows an early drawing of a square. Nothing very exciting yet...
An arrow! This is more like it.