Troubleshooting command center
Find the failure path before you change random wires.
Start with the symptom you can see. Then use the right guide or tool to check power, pins, I2C, upload, wiring, modules, and PCB readiness in a sane order.
Start here
What is failing right now?
Start here if WiFi, relay, servo, GSM, or camera activity makes the project unstable.
I2C OLED, LCD, RTC, or sensor not foundRun the scanner first, then use the address in your display or sensor library.
Upload Arduino or ESP32 upload failsFix USB cables, drivers, board settings, boot pins, COM ports, and serial conflicts.
Relay Relay stays on, clicks wrong, or resets boardCheck active-low logic, COM/NO/NC wiring, coil power, and boot-time GPIO states.
Free tools
Use a calculator before you buy parts or order a PCB.
Power Supply Calculator
Estimate current and catch brownouts, relay noise, SIM800L bursts, and servo spikes.
ESP32 Pin Checker
Check safe, risky, and avoid pins for ESP32, S3, C3, and ESP32-CAM projects.
I2C Scanner
Find OLED, LCD, RTC, EEPROM, and sensor addresses with copy-paste code.
Reliability Score
Score power, wiring, isolation, firmware debugging, and PCB readiness.
Featured fixes
Most useful guides for stuck projects.
ESP32
ESP32 WiFi Not Connecting
SSID, 2.4 GHz WiFi, router settings, power, status codes, and minimal test code.
GSM
SIM800L Power Troubleshooting
Fast blinking, reset loops, AT failures, and network registration issues.
Camera
ESP32-CAM Not Working
Camera init failed, FTDI wiring, brownouts, upload mode, and WiFi stream.
ESP32 fixes
ESP32 WiFi Not ConnectingSSID, 2.4 GHz, router, power, and code checks. ESP32 WiFi Keeps DisconnectingDropouts, reconnect logic, WiFi sleep, and power dips. ESP32 Upload ErrorBOOT button, COM port, USB drivers, and boot-sensitive pins. ESP32 Keeps ResettingBrownout, watchdog, relay noise, and weak 3.3V rails. ESP32 Relay TroubleshootingActive-low logic, relay power, GPIO, and load wiring. ESP32 OLED TroubleshootingI2C address, SSD1306/SH1106, blank display, SDA/SCL.Arduino and sensors
Arduino Not DetectedCOM port, CH340 driver, USB cable, board selection. Arduino Upload Erroravrdude, old bootloader, RX/TX wiring, reset, port busy. Arduino Sensor Not WorkingNo reading, zero values, libraries, wiring, raw serial checks. HC-SR04 Not WorkingTrigger/echo, ESP32 echo voltage, timeout, and target checks. Servo Motor JitteringWeak power, missing common ground, noisy signal, overloaded linkage. DHT11/DHT22 Showing NaNDATA pin, sensor type, pullup resistor, timing, and code.I2C, displays, modules
I2C Device Not FoundSDA/SCL wiring, pullups, ESP32 pins, address scanner. LCD 16x2 Not DisplayingBlack boxes, contrast, 0x27/0x3F, LiquidCrystal_I2C. Relay Module Always OnActive-low trigger, NO/NC wiring, floating input, boot state. SIM800L Power TroubleshootingCurrent bursts, capacitor, antenna, SIM, and 2G availability. SIM800L No AT ResponseUART TX/RX, baud rate, line endings, ground, and power.PCB readiness
Breadboard to PCB ChecklistValidate the circuit before converting jumper wires into hardware. KiCad to Gerber ExportPrepare fabrication files for PCB manufacturing. Electronics Starter Kit IndiaWhat students and makers should buy first, skip, and upgrade. PCB DFM ChecklistManufacturing checks before sending files to a PCB fab. PCB Manufacturing ChecklistGerbers, drill files, BOM, assembly notes, and first-board checks.Free rescue pack
Keep the troubleshooting checklist beside your bench.
Get power, wiring, module isolation, buying, and breadboard-to-PCB checks in one printable pack.