This week I worked on getting the forwarding of connection and keypress data from the auxiliary BLE receivers to the main BLE receiver. I also modified the software of the main BLE receiver to be reprogrammable over UART. The first thing I did was consider the possibility of setting up a network where the 2 secondary BLE receivers would then connect to the main BLE receiver and forward the keypress data. However, I decided that this idea would not be feasible since the BLE latency from a direct connection was already over half the use case requirement of 50ms at 37.5ms, so adding a second jump for the connection would not be feasible. My solution to this issue was to physically connect the 3 microcontrollers. Since they all have the same pin footprint, I simply soldered headers that allowed the microcontrollers to stack on top of each other, transmitting the key press data in the form of pin signals. Receiver 1 is tied to pins D2-D6 and receiver 2 is tied to pins A2-A6. Whenever a key event is detected, the pin is set to the corresponding level. This adds a negligible latency, as when testing with the 240 fps slow motion camera on my phone, the latency was still 9 frames even when connecting to the bottommost receiver in the stack. Additionally, I implemented the protocol to receive the programming commands over UART. The main receiver will then parse the received string and determine what the new key assignments should be.<\/p>\n
My progress is on schedule, and I have finished pretty much everything needed for the project.<\/p>\n
Next week I will be working on the presentation, final report, and preparing everything for the demo.<\/p>\n","protected":false},"excerpt":{"rendered":"
This week I worked on getting the forwarding of connection and keypress data from the auxiliary BLE receivers to the main BLE receiver. I also modified the software of the main BLE receiver to be reprogrammable over UART. The first thing I did was consider the possibility of setting up a network where the 2 … <\/p>\n