Raspberry Pi

Power Supply Issues

• Lightning bolt icon = undervoltage — random crashes, corruption, weird behavior until fixed
• Pi 4/5 needs 3A+ supply — older 2A adapters cause instability
• USB peripherals draw from Pi's power budget — use powered hub for multiple devices
• Official power supply recommended — cheap adapters often can't sustain required amperage

Storage Reliability

• SD cards fail under heavy writes — databases and logs kill them within months
• USB boot with SSD for reliability — SD for bootloader only, root on SSD
• Quality SD cards matter — Samsung EVO, SanDisk Extreme; not generic cards
• Read-only filesystem for kiosks — prevents corruption on power loss

GPIO Dangers

• 3.3V logic only — 5V input permanently damages the Pi, no protection
• Check operating voltage of sensors/modules — many Arduino accessories are 5V
• Some GPIO used by default — I2C, SPI, UART pins need dtparam to free up
• Hardware PWM only on GPIO 18 — software PWM on others is less precise