improve speed control

[Armandpl]

• filter measurements
  • try exponential moving average
  • try kalman (what equations to use?)
• take esc dead zone into account?
• try higher control freq? like 50Hz
• get bytes instead of string from arduino
• change baudrate?
• use timer instead of time.sleep on the arduino
  • compute instantaneous speed from time between interrupts
  • compute the timeout and threshold from the slowest possible speed of the car

[Armandpl]

fun fact we control the steering and throttle at 50hz so no reason to go above that; dk if we could control them faster