- Risks
- IR seems to use incompatible photodiodes and receivers. We do not have a way to fix this, so we will just not use it. This was always a risk, and a big part of the reason we made sure to have multiple lasers was in case one did not work.
- Design Changes
- We are now using a usb power/data splitter for our usb cable. This allows us to use a usb pd source, like a wall charger, for power, combined with usb 2.0 data from a laptop. The board combines them into one cable for use on our board.
- We are now only using the green laser. IR hardware does not work, but green does. The green also appears potentially fast enough to meet our requirements on its own.
- The charge pumps are creating very large radiated emissions onto our photodiode traces. To deal with this, we are using only the charge pump which is further away from the green photodiode. This is far enough to not introduce noise onto the line. This is done with some resistors attached on top of the board, and the regular charge pump DNP’d.
- Updated Schedule
- We will continue working on integration for the next week and beyond as more subsystems are ready to work together.
- Progress
- The power splitter board came in, was reworked, and successfully delivered both power/data to the PCB. This splits the USB-C line from the PCB into power and data outlet, which can be connected separately to a power supply and a computer.
- The data path from FPGA to laser back to the FPGA was successfully verified at a speed of 6.25 Mbaud, even over just 1 laser!
- The board hardware is seemingly complete!
Anju Ito, Roger Lacson, and KJ Newman
