Most cases we need to interface 5V (TTL) logic level devices with ESP8266. For this you can simple use 1N4148 diode and one pull-up resistor.

The above circuit working can be understood using below figure.

1. When we give logic 1 i.e. 5V to TXD diode becomes reverse bias and ESP 3.3V RXD pin gets supply of 3.3V (Logic 1) from pull-up.
2. When we give logic low 0V to TXD pin the diode becomes forward bias and the voltage at its anode terminal drops below 0.7V i.e. logic zero.
3. For TXD pin of ESP we don’t need any circuit as we can read 3.3V as logic 1 and 0V as logic 0 using any 5V controller.

5V TTL Serial Communication with ESP8266

For serial interface you have two options go with 3.3V USB to Serial converter or use above circuit  to do level conversion and use 5V serial converter.

Serial interface is required to program the ESP flash.

ESP8266 require a sequence of input to enter into programming mode when programming is done using Arduino IDE. With few external components.

Continue reading Reset and Programming Circuit of ESP8266 →

ESP8266 operates at 3.3V and consumes around 100mAmp current, for designing of its power supply you can use LM1117-3.3V Low drop out (LDO) linear regulator which is having current capacity of 800mAmp. Remember that, this regulator is low drop out regulator. It is better to give 5V as input to the regulator to avoid over heating of regulator. You can create small heat sink on PCB using copper area.

Continue reading Power supply Design for ESP8266 →