The next sensor I have been experimenting with is an IR (infra red) sensor. This is the perfect sensor that can be activated with a simple TV remote control.
A 220ohm resistor in series with the IR sensor. This sensor is connected to the battery pack. Here is how it’s broken down.
Pin 1 is connected to the resistor and LED (anode or cathode??). Pin 2 (middle) is connected to the negative terminal of the battery pack. Pin 3 is connected to the positive terminal of the battery pack. LED (cathode, anode) are connected to the positive terminal of the battery pack.
A random TV remote control button is pressed to activate the sensor and turn the LED on.
Ensure that the LED is connected with the correct polarity by testing it with just the battery, then with the battery and resistor.