IR sensors:
fall off curve - there's a close distance where the readings fall off. this is problem because you end up with overlap.
hypersonic ranger: use sound (the way bats work). they have a much longer ranger, aprox 30 - 40 feet.
JST connector: black goes to ground, yellow goes to the sensor pin (A to D pin) and to a resistor which also goes to ground, and the red one goes to 5 volts.
Here's the last setup we had working with the pressure sensor and light sensor: