Sensors
Sensors are devices that provide feedback when there is change in the environment. A non-robotics example is our eyes. We use our eyes to take in information about the environment and use that information to adjust. When we see that something is far away, we move closer. Or when we see that something is going to hit you, you move out of the way. FRC robots have their own type of sensors as well. This page will cover the basics.
There are some FRC electronics that are mentioned here. So if you are new to FRC and aren't familiar with the different electronics, it is recommended that you check out the electronics page first.
When talking about sensors and how they can be used, new terms show up. The follow describes the terms, and their definition.
Axes is the plural of an axis. In a non-robotics definition, an axis is "an imaginary line about which a body rotates". An example of the imaginary line is that the earth revolves on its axis once every 24 hours. In a robotics/math definition, an axis is a fixed reference line for the measurement of coordinates. When talking about axes, there are 3 axes typically used for aircraft but they can also be applied to our robot. These axes are:
- Yaw
- Roll
- Pitch The photo below is a visual demonstration, created by FRC team 401, showing the three axes.
For robots to take information about their surrounding, they use electronic sensors. There are many different types of sensors that FRC robots use. The ones that are commonly used on the team are described briefly below.
A Gyroscope, or a gyro, is a sensor that measures rate of turn (the angle). They are very useful in FRC because they help with measuring and controlling the robot's direction. We have used gyros during autonomous to turn the robot a certain number of degrees in order to place/shoot a game piece.
For information on the software for this sensor, click here.
For information on the hardware for this sensor, click here
One type of Gyro that we have looked into using is the NavX. The NavX is very useful because it has more software features and more hardware features. There were plans in using the NavX during the 2020 season but it was not used due to lack of time. If you are interested you can learn more about the NavX at their website
An Accelerometer is a sensor that measures acceleration. They also have two different types: single axis and 3-axis. A sign axis accelerometer measures acceleration on one dimension. A 3-axis accelerometer measures acceleration in all three dimensions at the same time. Accelerometers can also be used to detect collisions.
For information on the software for this sensor, click here
For information on the hardware for this sensor, click here
Ultrasonic sensors are sensors that measure distance to an object using a high-frequency sound that we humans can't hear. If this term sounds familiar to you, that's because Bats use it to find food. However it is used different in FRC. We use a physical sensor and the sensor is commonly used to measure how close something is to the robot.
For information on the software for this sensor, click here
For information on the hardware for this sensor, click here
An Encoder is a sensor that measures movement, commonly used to track the rotations of wheels. We have used them on drive trains to move the robot a certain distance in autonomous. We have also used them on mechanisms. A good example of an encoder being used on a mechanism is on our 2018 robot. We set up an encoder to the elevator motor so the elevator had three set height position.
For information on the software for this sensor, click here
For information on the hardware for this sensor, click here
Digital Inputs are any sensor that can be connected to the roboRIO. An example that is commonly used on the team is the Limit Switch. The roboRIO can support 10 digital inputs. Digital inputs only have two states which are "high" and "low". The roboRIO will default the sensor to "high".
For information on the software for these types of sensors, click here
For information on the hardware for these types of sensors, click here
Cameras do count as sensors because we can use them to detect vision targets. We also used them to see and navigate the field during a match.