Learn the differences between RFID chip or ICs that make possible the development of wireless and battery-free RFID sensors.
We’ve been long discussing about RFID sensor tags in this blog. From high level technical approaches to application side posts, lots of information has been shared on autonomous sensing, IoT, M2M and such trends.
However, we never posted about the basis for such developments: the RFID chip or IC.
There are multiple RFID ICs in the market. Just type RFID chip or RFID IC in google and you will be able to find multiple chip manufacturers in the first two pages.
What to look for in an RFID chip
Apart from key specifications which are valid for standard identification solutions such as read range (sensitivity in RFID chip specs) and operating frequency and temperature, when talking about battery-sensor tags you need to pay special attention to different specifications:
- Power output – if you want to develop battery-free sensors, actuators or any other device this is a must. The RFID chip needs to have a power output you can connect your device to.
In this sense, you will also have to check what the power output is to understand if your device can effectively be powered up by the RFID chip, if a start-up circuit will help of if you definitely need to look for a different model of your device with different power requirements.
- Communication protocol for devices – Not the wireless communication – which should be EPC C1G2 – but the communication protocol with your device.
Standards such as SPI or I2C are quite common but it all depends on the device you want to use. In case it has a very specific protocol, you can always add a microcontroller to act as a bridge between the RFID chip and your device.
PLEASE NOTE that the RFID chip can have a master or slave module. Master means that it actually commands the communication – start, stop, etc. – while the slave has to be commanded by the master.
It is an important detail as you will have to decide which device has the control over communication. Take into account that in a battery-free mode, the RFID side has power before the device side when deciding how to design your solution.
- Wireless protocol – make sure your battery-free device will work with any of the RFID readers in the market. You should look for EPC C1G2 RFID ICs that explicitly say that no custom commands are required for sensing solutions.
You will have to develop the software for specific readers – reader manufacturers don’t provide the SW for sensor tags – but make sure you can do it with EPC C1G2 standard commands using the APIs provided by the reader manufacturer.
There are of course project specific characteristics you will need to keep into account but these are the key generic specifications in all cases for sensor tags.
I hope this helps you select the RFID chip you need for your battery-free sensor or actuator development. For any further assistance you can reach us at firstname.lastname@example.org.
Good luck with your solutions!