Cheap and effective chain wear indicator

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The initial design involved utilizing two optocouplers as optical switches or slot sensors. The optocoupler consists of a transmitter and receiver, with the sensor responding to interruptions in the beam caused by opaque objects. By placing the sensors at a specific distance L, the behavior of the chain can be determined. If L equals the normal length (Lnormal), both sensors will emit identical signals when the chain moves up or down, indicating no wear. Conversely, if Lextended exceeds Lnormal due to wear, the sensor signals will not occur simultaneously, introducing a phase shift that can be processed by a microcontroller. This concept can also be implemented using magnetic (inductive or Hall effect) or capacitive sensors, which are less sensitive to dirt and dust and do not require external protection from light. Mechanical switches can be used but are prone to wear and tear, making contactless sensors a better choice. An advanced version of this idea involves utilizing an optical linear sensor (CCD or CMOS) similar to those found in office scanners for paper documents or cash machines for banknotes. In addition to detecting extension wear by phase shift control, the optical linear sensor can identify cracks, nicks, gouges, visible distortions, severe corrosion, and sudden changes in edge or color. It is also possible to compare images from the sensor with a stored pattern of an unworn chain for enhanced accuracy. However, considering the price of linear optical sensors (ranging from $10-$15) and the availability of webcams at similar prices, it may be more cost-effective to use camera matrices as linear sensors. Advanced technologies like 3D laser scanners or shadow scanners can also be employed for surface control, but they require powerful software to process the data effectively.