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PN532 NFC/RFID TX Output Wattage
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PN532 NFC/RFID TX Output Wattage

by robert_murrell on Fri Jun 11, 2021 11:25 am

What's the output wattage on the PN532 NFC/RFID? I'm looking to drive a passive e-paper display and its optimum wattage in the 13 Mhz range is ~ 1.4 Watts. It can work with less but is error prone. I am able to drive the display with my phone NFC, which I'm pretty sure isn't at 1.4 Watts. Thoughts? Here is the display I'm using: https://www.waveshare.com/wiki/7.5inch_ ... ed_e-Paper

I will be using the Adafruit HUZZAH32 – ESP32 Feather Board as my controller but looking for something Adafruit to drive the NFC. Thanks!

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Re: PN532 NFC/RFID TX Output Wattage

by mikeysklar on Mon Jun 14, 2021 5:04 pm

Wow, that is cool. I didn't realize people were powering displays with NFC readers.

Looking through the PN532 datasheet it looks like the chip max current is 140mA. I've seen reports on this board drawing up to 160mA during tag reading activity. If you are going to use a 3v board like the Huzzah the max wattage might be in the .5W range. Maybe .8W if you were going on a 5v setup.

https://cdn-shop.adafruit.com/datasheets/pn532ds.pdf

This would be quite a bit below your display requirements. What do you think your phone reader is outputting?

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Re: PN532 NFC/RFID TX Output Wattage

by robert_murrell on Thu Jun 17, 2021 11:10 pm

My phone is probably around the same as the PN532. That being said, it is sometimes fickle with my phone even. I guess I'll have to look at another option. *sigh* just means more C code I gotta write... :/

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