This board has an ESP8266MOD WiFi module on it and a CP2102 USB to Serial interface on it.
The problem with both boards is when I plug them into my computer (running Linux), they do not show up as a USB device.
I have other CP2102 breakout boards and these "just work" on my computer. They are seen as "/dev/ttyUSB0".
I tried using short, sturdy USB cables (making sure the board had a good connection to the USB). I also tried a 1000 uF capacitor across the 3.3 volt board supply and the 5.0 volt incoming USB power.
Upon powerup, a blue LED on the WiFi module flashes a few times, then stays dark. Pressing "reset" causes the blue LED to blink the same pattern, then stay dark.
Nothing seems to work.
I then took one of my CP2102 breakout boards and connected it to the TX, RX, 3V3 and GND pins of the WiFi board.
The board SOMETIMES would start up, displaying a few characters of garbage, then a readable string that something like "AI Thinker", but upon trying to type commands, nothing happened (no characters echoed, no response from the board).
I have 2 of these boards, and they both act the same way, so I'm quite sure the boards themselves are not bad (at least it seems unlikely that 2 would have the same exact problem).
Did you try plugging in the usb while holding down the 'flash' switch? That may be how you get it in bootloader mode? I don't kniw why the usb interface isn't showing up.
Did you try plugging in the usb while holding down the 'flash' switch? That may be how you get it in bootloader mode? I don't kniw why the usb interface isn't showing up.
That shouldn't fix the problem. My guess is that you received a faulty module. Tro hooking up an FTDI adapter and see if it works
Common enough Chinese board ... I have a lot of 10 marked "Lolin" and I use Linux Mint 18 with no issues. All the boards enumerate properly.
One of the biggest gripes I have heard about the NodeMCU boards with the micro-USB is that sometimes the reflow soldering process does not properly solder the USB connecting end to the breakout board which of course keeps USB from working. I have hot-air reflow in the lab and while the Lolin boards have not given me any problems, I have had a few STM32 Chinese clones that had to be reworked a bit.
I suggest taking a micro-USB that does not have the PC end attached ... that is, broken out for access to the wire. You already know ground and +5 must be working (the blue light flashes), so D+ and D- are suspect. Use a DVM on the Ohm scale to test.
I recently got the same NodeMCU. It had the same problems. I have connected to the UART with an external adapter - it worked. I looked at the CP2102 through a magnifying glass - one side was not soldered :o ! Chinese >:( ! I soldered the CP2102 reliable - now it works correctly !
P.S. Connection speed over UART for this chinese module usually is 78800
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