Risks:
One major risk in our project currently is interpreting data retrieved by the linear hall effect sensor. While this device met our specification needs, it is very sensitive to close-range changes in magnetic field. For example, moving a magnet across the magnetometer will cause high peaks and lows on the graph produced by our Arduino, signifying great changes in the magnet field. However, moving a far magnet across the magnetometer produces little change in the magnet field. This behavior will force us to do extensive signal processing to interpret the magnetometer data so we can 1) establish a baseline sinusoidal for when the carrier is regularly moving along the track and 2) properly detect peaks in the magnetometer from the speed coils or approaching a stop (another magnet).
Another risk comes from creating a stable carrier. Currently, the prototype for the one-to-one carrier and track magnet design levitates but is sensitive to sudden movement, even when the sides of the track are elongated. Given we have not tested this design with our speed up coils, this can cause some problems once the train starts to move. We were previously given a design suggestion from course staff that have attempted to implement. This design involved a one-to-two carrier and track magnet design. However, due to gaps between magnets in the track, the sides of the carrier magnets would be attracted to the sides of the track magnets due to the gaps in track. Given that the magnets are circular, we could not come up with a solution to this problem without considering buying smaller magnets to but in these gaps or using new, straight magnets instead.
We found with our current propelling coils that we are not generating as much force as we would have expected. We need to make sure that we have the coils as close to the carrier as possible to ensure the magnetic field is at its strongest. We also will look to replace the bolt in the middle of the coil with a plastic core to reduce the inductance of the solenoid so that we do not need to drive as much voltage to our bridge.
Design Changes:
Spacing between the magnets has further reduced in the straight-away one-to-one design to 0.5 cm between each magnet in the track and carrier. Spacing for the straight away two-to-one design has changed from 1cm to 0.5cm to no space. Given the problems with this design, we expect to see more changes in the following week. Make our propelling coils larger in hopes of creating larger magnetic field strength, and replacing the steel core with a plastic or somehow an air core.
Schedule Change:
We have changed our schedule to be more accurate to our current design, responsibilities, and progress on those responsibilities.
