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ST25R3916 NFC RFID - Phone Detection

berkayCinci
Associate II

Hello,

Is it possible to detect a phone using NFC/RFID readers?

I am working on a wireless charger unit and trying to detect credit cards. When I put a mobile phone with a credit card, I am not able to detect credit card because phone is getting started to charge. I want to learn whether it is possible to detect phone using ST25 NFC Readers. 

Is it possible to read Q value of NFC side? After we talked with the vendor of power transmitter, he suggested us to read Q value of NFC side. 

14 REPLIES 14

Hi,

if tag and phone enter at the same time then RFID should detect the card and prevent Qi operation, right?

Ulysses

yusufekici
Associate II

Hi Ulysses,

Yes, that's what we want to do.

 

 

Hi Berkay,

Are you fine with the explanations: Always perform NFC polling (rfal_cd) before Qi to avoid damage to pure NFC cards.  This should also handle the case of both being brought together into the field.

BR, Ulysses

 

yusufekici
Associate II

Hi Ulysses,

I am ok with performing NFC polling before Qi to avoid damage.

However I need a mechanism to initiate NFC polling via a phone placed on the NFC. If no RFID tag is detected, the charger should proceed to the Qi state. If I simply poll for an NFC check and then move to the Qi state, there is a risk that the charger might enter the power transfer phase before detecting an RFID card. Therefore, we need an initiator (phone detection) to start this process.

Hi Berkay,

Sorry but I fail to understand the scenario you are describing. Can you add some flow/sequence diagrams? Or at least a written order of actions?

BR, Ulysses