Characterization and Performance of an Optical-Relay Switching System for Cost-Effective Multichannel Sensing Arrays

Multisensor technology is now commonly used in many applications to monitor a wide range of complex systems. In many cases, the outputs from the individual sensors are multiplexed through relays or electronic switching systems into the detection and signal conditioning electronics so that only one set of measurement equipment is required. These switching systems are often very expensive and limited to relatively benign laboratory-type environments. Within the work presented here, the performance of commercial off-the-shelf (COTS) optical-relay ICs within a digital switching system is characterized to access their suitability in a cost-effective switching system. A low-cost (sub £(30) optical-relay switch system (ORSS) is developed and characterized that achieves remote switching speeds of over 2800 switches/s. Combining the ORSS with a sourcemeter results in measurement speeds of up to 66 sensors/s with less than 1% error compared with measuring the sensors individually. Finally, in demonstrating the application of the ORSS, multiple temperature sensors were used to monitor the temperature profile of a microcontroller board where a clear temperature profile for the individual components and the printed circuit board (PCB) is measured. Hence demonstrating that this ultrafast and cost-effective ORSS can be used for a wide area of applications including large-scale device characterization, monitoring multichannel sensors for workplace safety, or data acquisition in industry and academia.