All detection systems are characterized by the same set of parameters, whether they are detecting incoming missiles, gasoline in a fuel tank, or the Higgs boson. Engineers recognize these parameters as sensitivity, selectivity, noise rejection and signal discrimination, among others.
Figure 1. Industrial Leddar™ Sensor counting objects on multiple conveyors simultaneously
─ Source: LeddarTech
This is true whether the sensing system is detecting traffic movement, liquid levels, materials moving through an automated factory process, or any other application.
Engineers who are designing a detection system have to navigate among several common hazards, including the tradeoff between missed detections vs. false alarms, failure to perform due to reliability and environmental factors, and of course cost.
Occasionally, a new product comes along that provides a valuable addition to the range of possible design options. LeddarTech has recently introduced such a product— a light-emitting-diode (LED) based sensing module. The module's compact form factor, ease of integration, low power consumption and high accuracy is meant to give developers and integrators flexibility to enhance their own branded products.
Figure 2. Signal travelling through the main components of a Leddar™ sensing module
─ Source: LeddarTech
Using light wave time-of-flight, the multi-element module processes the scattering from an infrared light source to a 16-segment receptor array to reconstruct an image using a proprietary software algorithm. This arrangement allows the module to detect objects quickly, accurately, ruggedly and inexpensively for a variety of applications such as production-line monitoring, vehicular transportation, and capacity sensing.
The Technology
Unlike laser-based technology, LEDs create a diffused beam that covers either a narrow or wide area. The receiver collects the backscatter from objects in the beam, accurately locating and measuring the distance of the detected objects using accumulation and over-sampling techniques.
The multi-element photodetector platform, because of its lateral discrimination abilities, can also reconstruct image ranges, physical profiles, and motion of the object. Since it doesn't need a laser source, it is lighter, more rugged and less expensive than laser-based technologies of similar resolution. The LeddarTech device is also said to have superior range compared to conventional photoelectric sensors.
The single-element photodetector platform provides a more focused, yet conic beam that is particularly suitable for applications like level sensing, which refers to the ability to measure such things as fluid levels in tanks. It is also well suited to proximity detection.
Applications
The company sees a variety of applications for these sensing modules. Among them are industrial production-line automation, unmanned vehicles, vehicular transportation monitoring, level sensing and security and surveillance, to name just a few.
Figure 3. Leddar™ sensors around a building provide an optical detection barrier
─ Source: LeddarTech
In industrial applications, the advantages of speed and accurate object profile recognition allows for detection of production line activity and problems.
In the realm of vehicular transportation, the device will find uses in traffic control, collision avoidance, vehicle classification/profiling (think tolls), and the increasingly important field of intrusion detection.
Furthermore, the detector exhibits low sensitivity to ambient light noise, so a given application can be expected to work particularly well in either daylight or darkness, and is not strongly affected by harsh weather. The company has a number of sensing application white papers that set out these applications in more detail.
The company includes a software development kit and Arduino library for investigating properties of the module, prototyping applications and integrating the device into larger systems. The kit includes .NET and C libraries, integration examples using LabVIEW and MATLAB, and sample RS-485 code for both Windows and Linux.
This device gives designers in a number of fields a new range of possibilities, especially in the application areas listed above. It appears to be easy to integrate into either existing systems or new designs. Sensor alignment and detector installation capabilities should also render it easier to set up and maintain than is the case with conventional detectors.
It is important to note that the number of segments and accuracy are not suited to applications requiring measurement or profiling of very small objects (e.g. dimensions smaller than the accuracy, which is 5 cm on the current models). And there are always the expected teething problems with all new technologies, however promising. On balance, this is a product worthy of notice.
There is also an evaluation kit available that allows potential users to try the technology before implementing it across the board. Consider it for your next sensing application.
Note: LeddarTech has sponsored promotion of their sensing solutions on ENGINEERING.com. They have no editorial input to this post - all opinions are mine. – Arnie Peskin