ESP8266 Community Forum

- Wed Mar 23, 2016 9:01 am #43878 dont believe to much with chinese, you'll just learn, "luck". or maybe fengshui. wahahaha

well, ill post it here if my first 5v powered esp stop sending me twillio sms and never reached its 2nd birthday on Nov. 1.

- Wed Mar 23, 2016 1:16 pm #43896 I've some sensors (e.g. a VOC sensor which requires 5V at least for heating) hooked up to an Atmega powered with 5V. The Atmega is connect to the ESP01/ESP12 using I2C without level shifters. The ESP itself is powered by 3.3V using a LM1117. The whole system is powered by a 5V/1A switching wall wart. This setup is stable for more then half a year now. I also secured the I2C transmission using CRC and I've only a very little count of broken checksums.

- Wed Mar 23, 2016 5:36 pm #43901 Diodes will work; typically 0.7V drop is used in calculations for silicon diode.

At a minimum you can connect Rx line with a 10K resistor. Forward biased body diode in ESP Rx pin will bring it to suitable level.

- Wed Mar 23, 2016 7:54 pm #43908 Simple MOSFET level-shifter such as the following is simply the best practice :

In case of Arduino hookup, R2 is not needed ...