I have a an RC522 NFC reader in fairly close proximity to a LOLIN V3 module. The Lolin is sending WIFI status to an iphone.
The NFC device, when powered on, is affecting the Wifi signal. When powered off the WIFI is working fine.
Both devices work at different frequencies so I cant understand why I am getting interference.
Please describe the equipment that you used to determine this, and describe how the WiFi signal was affected.
Also, considering the vast gulf between the NFC and WiFi operating frequencies, it would be good to know how closely spaced all the bits of equipment are.
How are the devices powered? Schematics could be valuable. Pen and paper is okey.
the wifi signal on my iphone drops when the NFC antenna is turned on.
both devices are powered from separate sources. the NFC reader is controlled by another arduino. I have asynch comms between the two arduinos. there is a common ground.
NFC reader is adjacent to the LOLIN board. about 1 cm apart.
Sounds like a problem with your iPhone. Post on the Apple forum to see if others have noticed a problem.
it also drops on my PC
This is not an Arduino problem, regardless of the root cause.
I was wondering how narrow the WIFI signal from an arduino or NFC is. and if anyone else had the same problem.
NFC operates at 13.56 MHz. WiFi operates at typically 2.4 and 5 GHz, for example in consumer routers. In most countries, all such commercial devices have to be agency certified to meet to strict transmission bandwidth standards.
Given that there are at least two orders of magnitude separating those frequency bands, it is nearly inconceivable that band overlap is causing whatever effect you see.
However, a receiver can be overloaded by having it too close to some transmitting device, leading to the appearance of interference.
Interestingly, according to law in the U.S. and perhaps elsewhere, that is your problem, not a problem that you can blame on the manufacturer of the transmitting equipment.
Thank you. very informative reply. appreciated
That is an indication that the input to the device is broadbanded and is being overloaded by the other signal. Frequencies have almost nothing to do with overloading of a receiver.
Apologies to all. It turns out the interference was not from the nfc reader but from another lolin board underneath the reader. That lolin has no Wi-Fi set and no Wi-Fi drivers but in proximity to the lolin with the Wi-Fi active it was causing wireless signal loss. Weird but I will raise this issue as a separate question.
Turns out a lolin board turns on the wifi as part of its startup. older versions of its internal core library do that. latest version reportedly does not, or you have to use the wifi library to disable the wireless.
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