Recently, I've been attempting to build an anti-collision detection system for uses in a car. I bought several nodeMCU units and wil use one as a WiFi hub.
In the course of experimenting, I broke off the micro-USB connectors of two of the units. I have since purchased a hot glue gun and glued the other two down.
The problem is programming without a USB connector. I've read elsewhere, a USB-to-serial adapter/converter can be used. The units are common and feature the FTD232RL chip with the power jumper set to 3.3V. I have several. What I've read states that the FLASH button is held down while the RESET button is "tapped." This establishes bootloader mode.
I'm not sure what I'm doing wrong, but this doesn't work for me. One of the two USB-less units contains a program that runs whenever I plug it in. That unit has a 5v power supply soldered to the Vin/GND pins. After trying to follow the steps, the original programs still runs when the unit is plugged in.
The Arduino IDE compiler attempts to connect to the unit via a Windows COM port but times out. When I hold the FLASH button down and push the RESET button, I then release the FLASH button. There is a quick blip of the blue LED, then the LED comes on and stays on for about 10-15 seconds. Is this to be expected?
I also tried with the other USB-less unit which has a couple of wire leads soldered to the ESP chip to replace a broken FLASH button. The same thing happens.
Any ideas? Am I doing this correctly? I've read this post:
This is the wiring setup: ESP USB2Serial
Tx / Rx
Rx / Tx
Vin / 5V
GND / GND
UPDATE: Apr 20; I've disvcovered several of my cables are not functioning as exprected. Fortunately, three are.