ESP8266 Community Forum

- Tue Oct 25, 2016 3:33 pm #57111 I can confirm that this setup works 100%:

Arduino is connected via USB.

ESP01 is connected to 3.3V pin. It is connected to WiFi network, send/receive MQTT messages, read/write UART.

I use newest NodeMCU firmware
Arduino: http://www.ebay.com/itm/SainSmart-UNO-R3-Board-ATmega328P-ATmega16U2-Free-USB-Cable-For-Arduino-/300948763268?hash=item4611f1b284:g:HygAAOSwB4NWxX3K

- Tue Oct 25, 2016 3:58 pm #57112 So, you are lucky then, because several hundreds of people report errors and complains ...

Make sure you at least add a capacitor such 100uF or 220uF nearby VCC/GND pins of ESP.

EDIT : Oh ! I think the SainSmart UNO R3 doesn't use the LP2985 regulator, and there is a switch to toggle the whole board between 3.3V and 5V, I didn't found schematic yet, probably the regulator is stronger, that would explain why you don't have issues like others.

- Tue Oct 25, 2016 4:09 pm #57114 Just tried to connect ESP01 to 5V pin of Arduino and use regulator lf33cv. I havent capacitor right now so I was not able to test it now.

I still got corrupted text (ESP is still not able to send correct text). But it is now constant string(every time same wrong characters). That is change, previously it was random characters or nothing sent at all.

Still have no clue why it work with USB connected