ESP8266 Not Booting Properly on First Power On – Works After Restart

Question

I'm working on an ESP8266-based water level monitoring system using an ultrasonic sensor and an I2C LCD. The problem I'm facing is that sometimes the ESP8266 does not boot properly when powered on for the first time. However, if I turn the power off and on again, it boots and works fine.

Project Details

Microcontroller: ESP8266 (NodeMCU)

Peripherals:

Ultrasonic sensor (JSN-SR04T)

16x2 I2C LCD

Buzzer

Push button

Wiring:

const int trigPin = D3; 
const int trigPin2 = D8;
const int echoPin = D0; 
const int echoPin2 = D6;
const int overflow = D4; 
const int buzzer_out1 = D5; 
const int push_Button = D7;

LCD Connections:

SCL: D1

SDA: D2

I2C Blank Text

Issue Description:

When I first power on the ESP8266, it sometimes does not boot properly. The LCD either remains blank or shows a pattern of blocks (see attached image). If I turn off the power and turn it back on immediately, the ESP8266 boots and works correctly. The issue is inconsistent but happens frequently enough to be a concern.

Any insights on what might be causing this and how to fix it would be greatly appreciated!

• jsotola: possibly a problem with the code
• johnson veigas: But most of the time esp boots properly Without any issue, so might be issue with my pin selection or wiring
• Matt: What is "overflow" (d4) ? Please, show full schematic.
• 6v6gt: This is for an ESP32 but the situation is the same for the ESP8266 where the enable (EN) pin is broken out: reddit.com/r/esp32/comments/ou6r8d/… The idea is to delay enabling the device for a few milliseconds after power is applied to it to help ensure the power is stable. But also add some details of the power supply to your question.
• johnson veigas: I am using 5V adapter connected directly to Vin pin of ESP8266