The ultimate goal when a robot is built is to be optimized and to be compliant with all specifications. To meet the requirements sometimes you can spend many hours just to sort and identify the sensors that would be the best for an application like detecting and tracking an object. In this article, we explore all sensor types that can be used for target detection and tracking as well as features and the types of applications where they can be used.
Selecting the right sensor is not a strict process. This is about eliminating all the wrong choices based on a series of question aiming to eliminate first the technology that underlying the sensor and then the product that it doesn’t fit to the robot requirements.
When we use the word target, we refer in the same time at a small ball, at an object like a chair, or even at a human that stay in front of the robot.
To select the best sensor from a variety of products and manufacturers is a hard work especially when you’re a beginner and try to build a simple robot. In few words the sensor has to be selected in concordance with your targets size, shape and range. All of these three features have to be on the same line with the specification of the robot. But even so, it is hard to define the best sensor since the performance and precision of this depend on many factors.
A sensor is a sophisticated device that measures a physical quantity like speed or pressure and converts it into a signal that can be measured electrically. Sensors are based on several working principals and types of measurements. In our case almost all types of sensors emit signals and measure the reflection to make measurements.
There are many sensors that can be used for a simple application like line following (IR LED and a Photodiode, LED and LDR, etc.), but this is a simple case when a simple sensor can be selected. A complicated case is when you have to track an object and the budget is limited to purchase a mini computer like Raspberry Pi. In this case it can be used an ultrasonic sensor to scan from side to side till the sensor detect a drop in distance (at this stage it detects the edge of the object and from now on the sensor see only the background). The scanning process continues back to the point where the object is with left and right scanning.
This is one of the cases when expensive products can be replaced with cheap sensors. Continue Reading →