125kHz reader problem - 0000000000 ids

Other Hardware Sensors
1

Hi

I have currious problem with my 125KHZ EM4100 RDM6300 RFID reader. Its running for few months now but sometimes there is some issue with the chip reading. It happens very rarely but in one case when one person used the chip the reader was keep reading the chip again and again for several minutes even when the person was long gone (I had some suspicion that the problem could be relatet to the chip itself because it was some new type different then the rest of chips we are using right now and this suspicion is becuase so far this glitch was only related to the people with the new chip).

But few days back even more strange problem showed up. The RFID reader suddenly keep reading chip of a person that wasnt even here, again it was repeating for several minutes like if someone would hold the chip above the RFID reader but I check the security camera feed and noone was near the reader in that time - about 8:55 AM. And last use was day before at 23 PM so threre were hours of "inactivity" and I have to say that this person whos chip was popping up in the reader was not the last person that night. There were two other people after him so if this would be some memory problem I would understand that some glitch would call the last person, not the 3rd last person data... I have no idea how this could be even possible :((

2

Well, if it's not in your hardware, then it must be a problem with your software.

Paul

3

Thanks, I really wouldn't think of that... :confused:

I know there must be something causing this but pleas can someone help me with something more specific than this? I solved half of this by debuging the logs and records and here is what i found:

  • the reader start to read something on its own when noone is even close to it and the chip ID was like F000F00000
  • the code will correctly recognizes this as a non-existent chip
  • few minutes or seconds after this the reader reads ID 0000000000 - here was problem in my API, one bad if statment was leting the 0 through and select the last person from all users, this bug was fixed right now
  • this 0000000000 reads was repeating and repeating several times over and over
  • then again the reader read something else with ID like DDBDFFF1ED and again correctly recognized as non-existent chip
  • and few seconds after again the 0000000000

See the event in time (date time and chip ID):

2019-10-30 09:14:07 0000000000
2019-10-30 09:13:50 0000000000
2019-10-30 09:13:43 0000000000
2019-10-30 09:13:34 DDBDFFF1ED not found!
2019-10-30 09:13:17 0000000000
2019-10-30 09:12:22 0000000000
2019-10-30 09:11:27 0000000000
2019-10-30 09:09:10 0000000000
2019-10-30 09:08:49 0000000000
2019-10-30 09:08:36 0000000000
2019-10-30 09:08:15 0000000000
2019-10-30 09:07:40 0000000000
2019-10-30 09:07:23 0000000000
2019-10-30 09:06:41 0000000000
2019-10-30 09:06:23 0000000000
2019-10-30 09:05:54 0000000000
2019-10-30 09:05:26 0000000000
2019-10-30 09:04:50 0000000000
2019-10-30 09:04:05 0000000000
2019-10-30 09:03:58 0000000000
2019-10-30 09:03:28 0000000000
2019-10-30 08:57:22 0000000000
2019-10-30 08:55:56 0000000000
2019-10-30 08:51:41 F000F00000 not found!

I dont have any idea how it can read something when noone is near that thing and why there is some weird ID like F000F00000 and then just only zeros and zeros... and then egain some weird ID and after that again zeros....

Can it be from some interference (like wifi, radio waves or anything like taht) or you thing is some HW malfunction of the reader or arduino due to the long run time, temperature or just some bad component somewhere on the board ?