Hello. We’ve previously used the SparkFun RFID Qwiic Readers without issue, but are struggling with undercounting RFID scans and occasionally scanning an nonexistant (repeated identical - 3102000232) tag across multiple devices. We have not changed anything about the code or build, but did notice t…

Are you using more than one RFID reader on one i2c bus? Are you using python?

We are daisy chaining two readers, so I think that counts as running 2 on 1 I2C bus. Wiring diagram is attached if I am incorrect on that point. We are not running on Python. We use the Arduino IDE. Best, Marie ▶ (attachments)

Alrighty - have you disabled all but one set of pull up resistors on the i2c bus? You accomplish this by severing the traces labeled “i2c” in this photo (using an exacto knife or similar), be sure to leave only one set intact and re-try

Ah, when we tried that previously, we severed those jumpers on BOTH readers. We will try that tomorrow and let the systems run overnight and get back to you. Thank you!

@mariedoyle take a look at my posting, it might be the same issue. I also bought the first reader just recently. [image] Qwiic RFID wrong readings after 20 reads NFC & RFID frowning too bad since the reader we are discussing here is the only Qwiic RFID reader from Sparkfu…

Hello, We are trying the I2C jumper modifications on one of the boards currently. But now that I’m back in the office I was able to look at the chips on the “old” (7D/7C addressed reader) vs “new” (13/14). The new readers read: ATMEL355B2B TINY84-20U 231016U The old readers read: ATMEL355B2B …

@michaelheiml82 I’ve actually been in contact with @happy_kass about this and unfortunately they are different issues, BUT I’m guessing they stem from the same source. We only ever see 1 unique false RFID that reads <10 times in 24 hours, so it doesn’t sound as extreme an issue. However, we previou…

@TS-Russell maybe Sparkfun could sell us boards with the updated ATtiny84 firmware? We are woking with multiple boards so updating it in house will be difficult and we will end up damaging the boards

Im going to see what all is going on with stock (and future stock!) and let you know ASAP, hang tight for now I can say we’ll get a definite solution underway!

The last set of numbers on the chip are a date code for when the chip was manufactured in YYWW format. YY is the year, WW is the week in that year. Not sure what the last 3 characters in the date code are but the datasheet for that chip will tell you. (Probably what facility or production line with…

Question about changes to SparkFun RFID Qwiic Reader

Sensors NFC & RFID

TS-Russell July 29, 2025, 12:45pm 14

This thread has some new info Qwiic RFID wrong readings after 20 reads - #46 by happy_kass

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Question about changes to SparkFun RFID Qwiic Reader

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