pert:
Try selecting Tools > Upload Speed > 115200.You might consider buying a USB to TTL serial adapter. It's much more convenient than trying to turn an Arduino board into an adapter. They are available from all the places you would purchase electronics components (eBay, Aliexpress, Amazon, Adafruit, Sparkfun, etc.) for a reasonable price. They most commonly use either the FT232 or the CH340 chip. It's a useful tool to have on hand. I prefer the ones that come with the "FTDI header" pinout:
- DTR
- RX
- TX
- VCC
- CTS
- GND
That is the most standardized pinout, which allows you to plug it right in to many boards (e.g. Pro Mini). Some have DTR and CTS swapped, but that doesn't matter. You will want one that allows you to select 5 V or 3.3 V.
Speed was already set correctly.
I'm not exactly trying to repurpose an Arduino to be an adapter, I'm currently attempting to add networking functionality to it. The ESP8266 will need to send data over the UART serial connection, and be able to connect to my Adafruit IO MQTT account. I've got all the code I need, its just the trouble of uploading it.