Taking data from a sensor node via UART (Software UART) -> Get Timestamp from RTC -> Store that data into SD card -> On regular time interval Post collected data to Thingspeak using Bulk Data update API.
Issue I'm facing is while ESP8266 posting data to Thingspeak it remains busy to get back the response from thingspeak for successful posting. It takes 6 - 8 seconds normally and sometimes if internet is down it takes 25 - 30 seconds.
So during this time, ESP8266 not able to get data from Sensor node via UART.
Is there any way to get data via UART during the time of posting also???
I'm using
Arduino IDE
NodeMCU as ESP8266 board
Thingspeak REST API bulk update
UART communication between sensor node and ESP8266
Any other alternative way is also acceptable like instead of using UART, use SPI.