Learn how to use market available generic devices – resistance monitors – to develop your own battery-free strain gages or any other sensors.

Farsens has been working on developing wireless and battery-free sensor solutions based on RFID technology. Using standard commercial UHF RFID readers (EPC C1G2 compliant) we have managed to wirelessly supply and communicate with a variety of sensors – from temperature or pressure sensors to accelerometers or relays.

In our mission to help users develop your own battery-free sensor solutions, we have come to the conclusion that we should provide you with a generic version of our sensor solutions that you could use in a fairly simple way.

Monitoring resistance variations

The first outcome of our efforts in that line is the R-Meter. The R-Meter is a wireless, battery-free sensor tag based on our proprietary RFID IC (ANDY100) that allows you to measure the resistance value of the device under test (DUT).

R-Meter for battery-free strain gages block diagram

R-Meter for battery-free strain gages – block diagram

The main idea is to use the resistance dependent sensors of your preference and make them wireless and battery-free instead of sticking to the sensor references already available in Farsens’s portfolio. Ambient light sensors (LDR), thermistors and soil moisture sensors are just some of the sensors that you can use with the R-Meter.

Developing new sensor tags – Strain gages

An alternative to using different sensor references to monitor the same magnitudes is using sensors to monitor different magnitudes. The battery-free strain gage is a good example.

We just developed a new demo with a resistance dependent strain gage by using the R-Meter. When signal conditioning circuits are required to amplify the signal you will require more energy, thus reducing read range or sensor performance. Please have a look at our “How to” series to learn more about power management in battery-free sensor tags.

Full passive strain gages are an interesting solution for a variety of industries such as:

  • Construction – Structural Health Monitoring (SHM) is a very hot topic these days. Being able to monitor the status of a bridge, tunnel or building so that an intelligent maintenance can be programmed based on objective sensor data
  • Manufacturing – many industrial products require of thorough stress testing. Wireless and battery-free strain gages can help users reduce set up time and even think about new set ups without wiring limitations.

Monitoring deformation is a very wide topic. Technology now brings you a new opportunity to embed strain gages in devices that can be placed in hardly accessible locations because they need no wiring nor battery changes, ever!