Overcoming Complex Challenges in Sensor and Automation Systems

Throughout my career as a systems engineer, I have encountered numerous challenges that required innovative solutions to achieve the desired performance and reliability. In this article, we will explore some of the most difficult problems I have tackled and the strategies I employed to overcome them.

1. Long-Lasting Wireless Pressure Sensor

One of the most challenging projects I undertook involved developing a long-lasting wireless pressure sensor based on a vibrating wire and a steel membrane. The objective was to ensure the sensor could operate for 10 years, sampling every 10 seconds, with a 500mA sealed lithium battery as the power source. To achieve this, I leveraged my experience with spread spectrum technology to design a unique signal transmission method.

The process involved hitting the wire with a 10-pulse set of wide-spectrum frequencies, followed by an idle period, then waking up the computer and sensing the vibration, narrowing the spectrum, and hitting the wire with the expected frequency. The computer then went back to sleep for half a second, waking up to measure the time of zero crossings for exceptional accuracy. The PCB was encapsulated in a 1/2 inch round tube that could withstand up to 1000 psi, ensuring the integrity of the sensor over time.

2. Remote Operation of a Digger in a Dangerous Mine Environment

Another significant project involved operating a 5-story copper digger unit in a dangerous open-pit mine environment. In the late 1990s, I designed a learning system that recorded and logged sensor data as a remote control operator performed tasks in a safe distance. The system allowed the digger to operate independently based on these records, enabling the operator to control the process while ensuring safety.

3. Home Alarm System with Advanced Communication Security

Dating back to the 1970s, I designed and implemented the first home computerized alarm system. This was an innovative approach that used digital signaling over standard telephone lines, up to 10 miles in length. The system utilized a pseudo-random communication protocol that was later broken by university researchers as a form of near-encryption. The protocol ensured secure communication to a protected alarm premises, a feature that set it apart from existing systems that relied on tones and logic.

The system was designed for up to 16 subscribers, each with isolated pulse transformers for positive and negative signaling. The secure data transmission used a known pattern, similar to a rolling code used in car remotes. The communication security was enhanced by the fact that the competition did not even use computers for their systems, ensuring a level of protection that was unique at the time.

4. Protecting Safes and Vaults with Advanced Technology

Other notable projects include protecting safes and vaults using fiber optic cables. These systems were designed to detect thermic lance attacks by analyzing sound vibrations while ignoring noise from a subway underneath. Additionally, I developed a double-redundant radio control system for mining equipment and a radio control system for a mine sweeper, attaching the controls in just two hours.

In another project, a probe was designed to detect water level changes at 100 feet below the water's surface with 1/100th foot resolution. This probe utilized a barometer above the ground as a reference, significantly enhancing the precision and reliability of the system.

These projects showcase the diverse challenges faced in the development of advanced sensor and automation systems. The solutions involved a combination of innovative thinking, practical engineering, and a deep understanding of the target environments and applications. Each of these projects has contributed to the advancement of technology and has provided valuable lessons in problem-solving and system design.

Conclusion

The projects detailed in this article highlight the complex challenges and innovative solutions that defined my career in sensor and automation systems. From developing long-lasting wireless sensors to creating advanced communication protocols and secure protection systems, these projects have not only pushed the boundaries of technology but also ensured reliability and safety in diverse and challenging environments.