It should be noted that Vernier offers a wide array of sensor types, but this tutorial applies specifically to Standard sensors only (those with BTA or BTD connectors). Go Direct™, USB, and Wireless sensors are not addressed in this tutorial.
Standard Vernier sensors come in two basic types:
ANALOG SENSORS (BTA)
Standard analog (BTA) sensors require a 5-volt source and produce a voltage that can assume any possible value between 0 and 5 volts. You can use the Arduino to provide the source and measure this voltage. Most Vernier sensors, including temperature, force, light, and sound, are analog sensors. Analog sensors have a 6-pin BTA connector.
DIGITAL SENSORS (BTD)
Standard digital (BTD) sensors require a 5-volt source and produce a signal that is either HIGH (5 volts) or LOW (0 volts). For these sensors, we use a BTD connector, also with 6 pins, but with the tab on the opposite side. The Vernier Motion Detector, Photogate, and Rotary Motion Sensor are examples of digital sensors.