Hi All,
I am working on project based on TRF7960 and the object to be tracked is lithium ion battery pack. I plan to use mifare or equivalent tag on the battery pack.
TRF7960 will be used to the read the tag. The read range should be about 3-5 cm when the tag is on battery and upto 8-10 cm when not on battery.
I should be able to read and write to the tag. The size of the tag will be either 24mm inlay or 40mmx25mm inlay that will be stuck on the battery pack.
Is this achievable with TRF7960?
Which protocol will suit this application - 14443A/B or 15693.
The Antenna for reader will be that used on TRF7960 eval kit - one to one copy.
Any help/feedback is greatly appreciated.
Thanks
Prithvi
Hi Prithvi,
If you mount the tag directly to the battery pack, it is unlikely that it will read at all depending on the metal composition of the battery. The tag will suffer from detuning effects. I would suggest providing at least a few mm's seperation of the tag from the metal. You can also find special ferrite material that can be applied to the tag and help shield.
With this in mind, I have attached the free space read range of the EVM and the different ISO 15693 tags that we offer. This is assuming the tag and reader are in parallel orientation. In order to acheive your range requirement, you may need to consider a larger reader antenna or larger tag antenna or higher Q antenna.
ISO 15693 will allow for longer range due to the lower bandwidth, hence higher Q antennas are possible. ISO 14443A/B can offer higher security though. What is the goal for this application? Do you require very high security?
Best Regards,
Eddie LaCost
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Hi Eddie,
Thankyou very much for the reply.
The Battery packs would be that of lithium-ion. Application is to track the inventory/supply chain.
I also read (on internet) that metal shielding is required to eliminate the effects of eddy currents that are induced which de-tunes the antenna.
As of now, the goal is to read from tag on battery pack. I may be able to manage a 1 or 2 mm separation but not more than that.
Security is not an issue since I can manage that by writing encrypted application data and reading that. My application should be able to handle that.
I see that inlays from TI are about 0.4mm thick and this perfectly suits my application and so does the cost.
So, now the question is how do I add this ferrite shield to TI inlays?
Regarding the read range - from the document you sent I see that 3-4 cm is quite achievable in open air. But still need to test with battery pack.
Second question is, it looks like reading and writing to tags is now a function of shielding the tag.
So, can I go ahead and use the TRF7960 eval kit as reference design to build my reader? There is always an option to add external antenna.
Thanks Eddie once again. Appreciate that.
Regards
Prithvi,
The Ferrite Shield material should attach to the tag with adhesive. You could assemble a few by hand for testing purposes and once you find something that works, have a label converter add the material using an automated process. I have included a few manufacturers of thin ferrite material below. You also may want to look at metalcraft who manufactures tags using our inlays with a foam type spacer.
http://www.ferrishield.com/html/RFIDShielding/RFIDabsorbershielding.html
http://www.delevan.com/seriesPDFs/FFAM.pdf
http://www.tdk.co.jp/tebck01/flexield_e/e/future_1.html
Metalcraft: http://www.idplate.com/
I think the TRF7960EVM would be a great platform to use as a reference design and for range testing. The kit also comes with a few sample tags.