Battery-Powered IoT MQTT Notifier with USB-C Power-Path Charging, Multi-Rail Power Architecture, and 3 s Long-Press PFET Power-Gate (MP5014 + LTC2955 + MCU SYS_EN Override) #power_control #long_press #load_switch #sys_en

Pocket Soundbox – LiPo-Powered Cellular I2S MP3 Audio Player (SIMCom A7670E-LASE, Nano-SIM, I2S MP3 to PCM5101A DAC, FM8002E Amp, 1.8V↔3.3V UART/PWRKEY Level Shifting, Remapped J4, MP2315 3.3V Power Path, USB-C ESD/TVS) with power ON/OFF long-press control via SW2 and Q2 featuring pull-ups, RC debounce, and PFET safety clamp (#Cellular #I2S #LiPo #Audio #powerbutton #debounce #PFET)