- Risks
- Communication between boards seems a lot more unstable than reflecting back to a single board. It is not clear why, but this may be due to aiming the laser needing to be very precise. We may need to reduce our requirement of aiming accuracy needed for the lasers to work.
- The receiver on the FPGA were encountering issues when tested by itself, which may be due to not using the PCB board. Currently, we are seeing duplicates, and the FPGA code may still have concurrency bugs that can be fixed to make receiving more accurate.
- Design Changes
- We realized it is pointless to include 2 lenses if we are only using one laser, so now each lens housing only holds a lens above the IR laser.
- The header sequence for each packet will now be 4 bytes instead of 1 for increased reliability.
- The packets will now be sent continuously (not waiting for a feedback) from the transmitter, and the receiver at the end will send back all the tags that are missed at the very end so that they can be resent.
- The tag ID byte length was changed from 1 to 4 bytes, so that we will never encounter a wrap around, making software easier to implement with relatively low cost in terms of packet size.
- The packet size will increase from the originally planned 64 bytes into kbytes. This decision was made because we figured out that the FPGA embedded memory that allows us to store that many bytes, and the C read/write functions were slower than expected, so batch operations can help lower the time needed per byte.
- Updated Schedule
- We will continue working on integration for the next week and beyond as more subsystems are ready to work together.
- Progress
- We sent data from one laptop to another through the laser! This was raw data, but it was a very big step to demonstrate that the entire pipeline works.
- We completed the second lens and lens holder assembly, so now both boards have complete mechanical setups.
Anju Ito, Roger Lacson, and KJ Newman