Results.
Our group has accomplished most of its individual objectives, except when those objectives are combined all together. Each addition to the original hovercraft worked as originally planned: analog-controlled directional/propulsion motors, remote-controlled on/off switch, and failsafe idle mode when hovercraft loses the transmission signal. However, our group did not anticipate the noise that would be generated by the three separate motors at the onset of this project. Therefore, during all individual testing phases, everything appeared to be working properly: the transmitter and receiver would send strong well defined signals, the directional motors received the correct analog values, and the main motor powered up and down currently. Once however, we placed them all together, the noise generated by the circuits, despite our best attempts at quieting it through numerous capacities, diodes, and separate power supplies, was too much for the MCU and receiver to handle.
Once the main motor was activated, it was virtually impossible for the rear motors to receive their correct values. Because we separated the power supplies, the hovercraft became weighed down with the additional batteries and seized to properly hover. And furthermore, the additional batteries, would not fit inside the original case.
We could not use the same
transmitter as the original either, because we needed to read in analog
inputs. The transmitter included with the original hovercraft was
rudimentary and there was no realistic way for us to place two
potentiometers within the assembly. However, we did decide to use a
the potentiometers from a Playstation2 controller instead, which provided
very nice spring-centered inputs for each of the two motors.
In terms of maneuverability, the analog controlled hovercraft is a big
improvement over the original hovercraft. The user has much greater control
in the turn rate, acceleration, and deceleration of the hovercraft,
ultimately leading to much greater enjoyment. And since we have made the
code to the hovercraft virtually failsafe, the user does not need to worry
about a runaway hovercraft if it loses the transmission signal.
Another improvement over the original hovercraft is the addition of the
power on/off button on the transmitter. Now, the user can turn the
hovercraft on and off whenever he/she wishes by simply pressing a button.
This is a definite improvement over physically having to go over to the
hovercraft to turn it off. It should be noted that turning the hovercraft
off while on water is not a good thing.
Our original idea to use DACs to vary the voltages into the motors proved
not to work, but the PWM worked extremely well, with very smooth transitions
from one magnitude setting to another. From the highest settings to the
lowest, there was a very noticeable change in speed yet there was no
“stuttering,” that we feared would happen at the lower speed settings.