Fix ESP32-SIM800L AT Response

@hhanumanthappa

I can help to debug this issue and help to identify the root cause. Sometimes board may not be properly connected or not working. We can discuss and resolve this issue

@hexabitzprojects

**Dear Client,** I have hands-on experience with **ESP32 + SIM800L, UART/AT-command communication, power management, and GSM integration**, so I can troubleshoot this systematically rather than guessing. The likely areas I would check first are **SIM800L supply voltage/current peaks, UART TX/RX direction, logic levels, baud rate, common ground, PWRKEY/startup sequence, and the specific red-board regulator design**. A single 18650 can work for some SIM800L boards, but the supply must handle GSM current bursts without voltage collapse. I can provide: * Corrected **ESP32 ↔ SIM800L wiring and power diagram**. * Clean Arduino code using `Serial2` on **GPIO26/27**. * Proper baud-rate initialization and AT-command handling. * PWRKEY/startup sequencing if required by your board. * Guidance for voltage-level compatibility and power conditioning. * Step-by-step remote debugging using your serial output or logic-analyser/scope captures. * Final verification that sending **`AT` returns `OK`** reliably. I have worked with **SIM800/SIM7670 and ESP32 cellular systems**, including MQTT/GSM communication and power-management considerations. **Please message me with the exact SIM800L red-board model/photo and your current sketch. I can review it and guide you through the fix in real time.** **Best regards,** **Subhash Suman** ESP32 | SIM800L | GSM | UART | AT Commands | MQTT | Embedded C/C++ | 15+ Years Experience

@warrick1718

This project immediately caught my attention because it is exactly the type of work I do best. Your need for hands-on guidance with the ESP32 and SIM800L pairing, especially in troubleshooting AT command responses, aligns perfectly with my expertise. I understand the importance of achieving a clean, professional setup that is user-friendly and seamlessly integrated. While I am new to freelancer, I have tons of experience and have done other projects off site. My skills include troubleshooting embedded systems, firmware development, and providing clear documentation, which will ensure you receive a concise set of working code along with a corrected wiring diagram. If this sounds like what you're looking for I'd love to hear more about your project. Regards, Warrick Van Eeden

@Rohit6397

Could you confirm the exact SIM800L red-board version you are using, the baud rate currently configured on the module, and whether the PWR/NET LEDs show normal activity after power-up? Also, have you measured the voltage directly across the SIM800L VCC-GND pins while sending an AT command?

@iampranesh17

I can troubleshoot your ESP32-SIM800L AT response issue, verify UART wiring, power stability, baud rate and code, and provide tested working code plus a clear wiring diagram to get reliable “AT” → “OK” communication.

@Qim1997

Hi, I can help you debug this ESP32 + SIM800L setup live. From what you’ve described, I wouldn’t start by changing random components or rewriting the whole sketch. I’d first isolate whether the silence is coming from the SIM800L itself, its power/boot state, or the UART link between the two boards. I work with ESP32/Arduino hardware and can walk through it systematically with you. We can start with a minimal UART test, verify the SIM800L state and supply under load, then check the RX/TX signals with your logic analyser if necessary. Once communication is confirmed, I’ll give you a clean working sketch and corrected wiring/power arrangement so you can consistently send AT and receive OK. I’m available to troubleshoot it with you in real time through chat and work from your measurements/results.

@remelareme92

I can fix your ESP32–SIM800L communication quickly. I’ll verify UART TX/RX, baud rate, voltage levels, power stability and firmware, then provide tested code and corrected wiring. I’ll guide you live until the module reliably responds “AT” → “OK”. I’m ready to start immediately.

@Yashwanthk2026

Actually i have worked on a similar project where i receive AT commands from SIM800L in Arduino for a FDAS project, and i think i might be handfull for you to solve this problem.

@paulpham93

I can isolate the ESP32-SIM800L failure quickly by checking UART pins, baud settings, shared ground, 4V supply stability, PWRKEY timing, and logic levels. I’ll provide a tested wiring correction and concise firmware fix, with serial diagnostics proving AT communication. My Upwork profile with account Paul.P. has earned over $300,000 on Upwork. Best regards, Paul.

@jefreyd

Hi, I am an Electronic Engineer with extensive experience in Embedded Systems, ESP32, and Arduino firmware development. I have successfully integrated SIM800L modules in multiple telemetry and IoT projects, so I am very familiar with this issue. The lack of AT command response between the ESP32 and the SIM800L is usually caused by one of three common factors: a mismatch in the UART configuration (baud rate auto-bauding issues), insufficient peak current during boot (the SIM800L requires up to 2A bursts even if powered by a 18650 cell), or incorrect hardware serial routing in the code. I will help you debug this by: 1. Reviewing your schematic/wiring to ensure proper ground sharing and logic level compliance. 2. Verifying the ESP32 hardware UART configuration in your Arduino IDE code. 3. Providing a clean, tested script to guarantee stable AT command communication. I can start working on this immediately to get your module responsive. Looking forward to your reply! Best regards, Jefrey Diaz P.

@techhelp24x7

I have 16 years of experience in vehicle tracking devices and work very closely and remotely on such kind of projects. Allow me to help you if it’s works for you then only pay else don’t need to pay , no advance once you like my work then only pay

@wahyu8912

Hello, I have previous hands-on experience working with ESP32 and SIM800L modules, including UART communication, power supply considerations, and AT command communication. I have successfully built and tested an ESP32 + SIM800L project, so I am familiar with the common issues involving TX/RX wiring, baud rate, logic levels, and SIM800L power stability. I can help you troubleshoot your current setup and identify the root cause of the communication problem. If you are interested, I can also prepare a short video demonstration showing a working ESP32 + SIM800L setup, along with: -Correct electrical wiring diagram -ESP32/SIM800L UART configuration -Working example code -Possible solutions that can be applied to your existing project We can then compare the working setup with your current configuration and troubleshoot it step by step. Best regards, tesa