[Solved] RMT collisions with UART?

[u063096]

Solution: see next post!

Since the RMT reception problems I am experiencing always occur when some kind of UART communication is going on - either the Serial output to the PC via USB or display commands via UART2 to a Nextion HMI display - could there be any interference between RMT and UART?
The RMT is working like a charm as soon as I will disconnect both USB and display UART connections. When either of these is plugged in, the RMT gets seemingly less (USB) or no (display UART) data anymore.
Huh...

[u063096]

The problem was the 433MHz receiver module, not the ESP32.

The cheap receiver modules all are amplifying whatever they pick up to a level where they are "seeing" data signals. This is the reason why most 433MHz protocols are sending some lead bytes with a recognizable pattern to let the receivers adjust to the signal level, thus reducing the noise.

In my environment the LCD display added a _lot_ of low-amplitude noise, that got amplified until it prevented the lead-in pattern to be detected.

The solution was to solder a resistor to two pins of the chip on the receiver module, that now is lifting the reaction threshold of the amplifying circuit to a level above the noise. Works like a charm

I found two solutions for two of the most used modules:

• SRX882 with PT4303 chip: https://www.mikrocontroller.net/topic/459520
• RXB6 etc. witch SYN470R chip: http://forum.espruino.com/conversations/268494/

[fabltd]

Hi

Do you have any info on how you got the RMT working. I am stuck but cannot find any help.

JT