How to choose a sensor for your robot?

5.Speed measurement sensors

The speed measurement sensors are mainly used to determine the wheel speed of the robot system. If the wheel speed of the robot is known, we can compute the distance traveled by the robot and the position of the robot. The estimation of robot position from speed measurement sensors is called ‘Odometry‘.

Here are some examples of speed measurement sensors

5.1 Wheel Encoders: The commonly used speed measurement sensors in robots are wheel encoders. The encoder circuit can trigger whenever a movement in the robot wheel/motor gear shaft/motor shaft itself. There are different categories of encoders. Here you can see the different technologies used in wheel encoders.

• Optical encoders: These encoders detect the wheel movement using an optical transmitter like LED and receiver like photodiode. It uses a wheel disc in-order to detect these changes.
  Examples: HKT22 Optical Rotary Encoder, US Digital encoders
• Magnetic (hall-effect) quadrature encoders: These sensors are using a hall-effect sensor in order to detect the motion of the wheel. A magnetic disc will be mounted on the wheel shaft, whenever the disc moves, this sensor will trigger.
  Examples: Pololu Magnetic encoder

6.Force/Torque/Touch sensors

Force/Torque/Touch sensors give a feel of touch. The robot can estimate how much force/torque robot exerting on the joints or the robot tip(end effector). Here are some examples of Force robot sensors.

Robotiq FT-300 Force sensor

7.Robot audio sensors

Audio sensors are basically microphone based circuits that are either used to detect a sound with a certain threshold, or processing the audio signals for speech recognition, speaker identification, etc. Here are some microphone based modules for detecting sound.

• DFRobot Gravity
• KY-037 Microphone Sensor Module

8.Robotic 2D vision sensors

These sensors are mainly digital cameras. There are different types of digital cameras available in the market. In robots, you can use from ordinary webcam up to industrial cameras like point grey.

Here are a few examples of 2D cameras.

1. Logitech Web cam
2. Prosilica GigE vision camera
3. Point Grey camera

Conclusion

This post was about discussing different kinds of sensors and their applications. This can give you an idea of how to choose a sensor for your robot. There are a different category of sensors, but in this post, I have categorized sensors based on the applications

Reference

• ROS Sensors
• Robotiq blog
• Velodyne LiDAR