General Overview

Passive sensor gathers target data through the detection of physical phenomena. A passive sensor is a which just ‘listens’ to what is happening, contrary to active sensors that need to transmit a signal into the environment and measure the response.

Passive sensor detects electromagnetic radiation emitted or reflected from a source. Sensor converts an external stimulus to an output signal.

Microwire is a wire of small diameter (on a micro-scale). RVmagnetics produces glass coated bistable MicroWires using Ulitovsky-Taylor method.

Calibration constant is the coefficient used to convert the value acquired by MicroWire sensor into physical quantity. For calibrating MicroWire sensors RVmagnetics uses standard calibration constant.

For electronic setup there is no general sketch, schematic or block diagram – it is always customized based on the existing design, limitations, noise levels, environment etc.

Power consumption depends on the measurement frequency and also depends on the electric and magnetic properties of the environment.

Pressure, temperature, position in the magnetic field, but also also electric current, torsion, stress, vibration … Read more about the measurement.

One MicroWire is sufficient to perform a measurement of e.g. temperature, mechanical strain, etc. More MicroWires are employed when use case requires creating the „heat map“ of a physical quantity. Sensing head is able to read multiple MicroWires in its vicinity,

Estimated cost of the sensor unit depends on the volume of R&D / customization work and also on order volume of sensors. In higher volumes (over 1 million units a MicroWire unit can be provided at a price below 1 EUR). Sensing head and electronics part varies significantly.

Technical Overview

We are measuring the time occurrence of the magnetization reversal process in the MicroWire. This is a unique magnetic response from the MicroWire to the external magnetic field. We separate the response from the measured external magnetic field(s) and from our excitation AC magnetic field. Read more about principles of measuring for MicroWire.

The accuracy and sensitivity of our custom developed sensor can be adjusted with chemical composition of the MicroWire, diameter of MicroWire, design of the electronics and other parameters. Read more about the difference between accuracy and resolution.

Now, the maximum range is up to 10cm in ideal conditions (low electric and magnetic fields). In presence of strong electric and magnetic fields, or „pushing“ the signal through several mm thick metallic / magnetic walls sensing distance shortens.

Our sensor generates a unique signal. In the case of strong interference, the response from the wire can be obtained simply by averaging of the received signal.

The longer the wire, the better the signal. Typically 1 cm sensor is ideal for sensing, but for some applications we use up to 4 cm long wire. In ideal conditions the shortest MicroWire of 6mm length can be used. Find out more about MicroWire in the basic technical overview section.