ESP8266 Community Forum

- Tue Apr 05, 2016 9:52 pm #44925 Would like to use an ESP-12E as a solar data logger for my solar inverter. The inverter has a serial port DB9 which outputs statistics every 10 seconds. Would like to connect ESP-12E to read these statistics and output them to thingspeak.com

What additional hardware components, if any, are required to be able to connect the ESP-12E to DB9 serial port?

- Wed Apr 06, 2016 12:08 am #44932 A software :https://github.com/dparnell/esp8266-ser2net

- Wed Apr 06, 2016 6:10 am #44949 Old serial connections where 5v, while the ESP should not be connected to anything higher than 3.3v; thus, you will probably need an adapter board.

- Wed Apr 06, 2016 7:27 am #44957 BTW, it is even worst : real RS232 signal is swinging between around -7V and +7V, inverted compared to TTL side, -7V is HIGH and +7V is LOW.

You need to use some interface chip such as MAX232, which built the +-7V out from 5V using internal charge pumps.