Small form factor RFID reader modulesJune 09, 2015
The RFID Application Development (or RADLab) has been involved in building RFID systems for three years now and in that time we've used several different reader types to augment our systems. Usually, this was achieved by utilizing an external reader like an Alien 9900 or an Impinj Speedway. They are great systems but when your requirements suddenly change and you need to create something much smaller, or just more portable, you have to start thinking about an RFID module that is a much smaller form factor and can be embedded in with the rest of your appliance or perhaps as a small add-on.
Though we've investigated several RFID modules that may have fit our requirements, we've settled on the ThingMagic M-Family of devices for most of our development.
The devices can support up to four antennas — but will do more if you need them and can work with ThingMagic's API for multiplexing — are small in size and the power required to read tags is relatively small.
The real power behind the M6e device is the API created by ThingMagic for use by their customers. With this interface, a developer is able to create applications which can utilize the reader hardware easily and relatively quickly. The API is built on top of the Low-Level Reader Protocol API, the de facto RFID industry standard that as ratified by EPCglobal in April 2007.
Once the device is wired into your device, via USB or Serial port, you're ready to write code that will access the reader's capabilities. One of our hardware gurus would be better prepared to talk about how the device is physically attached to the parent system so I'll leave that to them.
ThingMagic have provided Java, .NET and C interfaces for their users which comes in handy depending on your platform of choice. The RADLab has been playing in the small-form-factor space for some time now — RaspberryPI, Arduino, Olimex, etc. — these devices all run some flavour of Linux so it's almost a requirements that we'd use the C language API for writing applications for the ThingMagic device.
Usage of the API is simple when compared to what a developer would need to do in order to use the LLRP API directly. A high-level explanation of asynchronous read cycle using the ThingMagic API might be the following in C:
- Create and utilize a 'reader' code structure.
- Connect to the reader code structure via serial or USB.
- Configure the reader structure parameters required by your specific requirements.
- Do a single read cycle of user-defined length — in milliseconds.
- Gather tags read during the reading cycle and action accordingly.
- Repeat steps 4 and 5 until required.
- Clean up the reader structure (destroy).
- Exit application.
As you can see, the process is relatively simple, when compared to some of the other small form factor RFID devices. This is a very simple process for use by labs wanting to do RFID reads for any number of research activities.
By Chris Zaal