Nathan runs a company that rents high-end amplifiers and sound equipment to musicians, artists, and rock bands. While many of his clients hire experienced electricians, others improvise equipment and wiring, which could cause equipment to overheat.
Less experienced renters may not be aware of voltage drops and wire routing limits on stage floors. The reduced voltage at the remote end creates high internal temperatures in the equipment and, combined with the increased ambient temperature of the stage lights and overheating of the cables, the stage equipment can be damaged or reduce its useful life. Sensitive electronics wear out faster than Nathan expected, which means higher maintenance and replacement costs, all costs passed on to his customers.
Even with careful contractual language, how can Nathan monitor and verify operating temperatures to protect his investment or get paid when he knows equipment has overheated?
HF RFID detection enabled
Melexis has created the MLX 90129 sensor IC that can be combined with multiple sensor inputs and read with a Proxima RF 13.56 MHz Radio Frequency Identification (RFID) reader. With the MLX 90129, a simple and cost-effective temperature data logger can be connected to the rental equipment to verify operating temperatures with a portable reader on rental return.
The read/write sensor IC has an internal temperature sensor and three additional inputs for sensing or monitoring. By combining resistive sensing with high frequency (HF) passive RFID, Melexis opens the door to new sensing applications that were previously difficult to achieve. As an added benefit, HF RFID can use unique product identifiers for inventory and rental control, plus it can be password protected for added security.
What can make sense?
The Melexis Sensor IC can be used for more than just temperature sensing. Combined with virtually any resistive sensor on up to three sensors or monitoring ports, the Sensor IC can provide data via proximity RFID for monitoring applications including:
– Sensors of tension or force to measure small movements, stretches, weight
– Pressure sensors (air, liquid pressure, vacuum)
– Flow (liquid or gas)
– Temperature, humidity
– Electrical voltage, resistance and current.
– Tampering, tilting, breaking a seal
– Proximity of nearby objects or linear position
– Shock, rotation speed, angular position and light
– Run time, duty cycle, on/off
Detection without battery or data logging?
The Melexis 90129 sensor IC and combination sensors can be encapsulated in a number of different form factors; from tiny, inexpensive plastic casings to high-temperature and waterproof casings.
The complete sensor can be integrated into new equipment or construction to create an “in situ” battery-free sensing product for point-in-time data collection. Low power sensor IC with 13.56 MHz passive interface draws power from Proxima RF designed HF reader – this energy harvesting means designers can incorporate sensors into products and equipment where water and liquids are a problem for ultra high frequency (UHF) RFID.
By adding a battery, the sensor becomes a data logger, taking data points on a schedule that matches the needs of the application.
Why high frequency for sensors?
HF is a “proximity” read technology that has a short read range. The shorter read ranges are useful where personal human intervention is preferred or already part of standard operating procedure, such as in healthcare, high-security applications, or with sensitive or mission-critical devices. Personal interaction allows human verification of the reading and the environment, to add redundancy in the system. The short read range ensures 100% reads without interference or the need for anti-collision software, as is required with the longer read active UHF technology used in real-time location and inventory systems.
High-frequency 13.56 MHz RFID has superior performance characteristics in and around liquids, making it a logical choice for use with sensor systems used to monitor food, beverage, and liquid products, whether in control processes, manufacturing, transportation or storage.
The proximity reading nature of 13.56 MHz passive RFID results in fewer environmental emissions, a benefit in healthcare applications or anywhere emissions could create a concern with sensitive electronic equipment. The recent HIBCC ANSI 4.0 standard specifically recommends the use of HF in healthcare to reduce concerns that active UHF could interfere with sensitive equipment.
HF Readers – Desktop or Mobile
MLX 90129 based sensors can be read with the standard Proxima RF USB desktop reader or the AV-X mobile reader. The FCC/CE USB Desktop Reader has an internal antenna, so no additional parts are required. The small polycarbonate case draws power from the USB connection and includes an LED for visual read confirmation.
The Proxima RF AV-X Mobile HF Reader is designed specifically for the rugged Psion Teklogix Workabout Pro product line. The reader is designed to work with the other radios in the handheld: operator can maintain WiFi, code scanner Barometer or GPS running while taking HF reading. Since many users require mobile readings, the AV-X is perfectly suited for HF-enabled sensor applications.
Development of applications for sensors enabled with RFID HF
Melexis and Proxima RF have partnered to create the DVK 90129 Kit for sensor designers to easily evaluate the characteristics of the MLX 90129 sensor IC. The kit includes an evaluation board pre-loaded with a temperature sensor, light, and a potentiometer. The evaluation board is read with the Proxima RF USB HF Desktop Reader. The kit includes powerful drag and drop control panel software. An optional keychain-style temperature sensor (ST-KF1) can be ordered with the kit for developers who may be interested in testing the sensor in an application-ready form factor.
The DVK 90129 is available from Future Electronics or your local Melexis representative.
Why rock bands should care
Nathan, the equipment tenant, is like any business person; he needs to make sure he provides a quality product, protects his investment, and keeps costs down. If he finds that the life of his equipment is shortened due to overheating, he will simply charge more. But everyone saves time, money and headaches by instantly checking operating temperatures with a simple mobile reader. And the Rock Bands can make music again.