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Detecting and controlling mains voltages with a Raspberry Pi or Arduino | Experiments using a Raspberry Pi and solid state relays (SSRs) to sense the presence of mains electricity and switch loads
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Geekworm Raspberry Pi 4 X735 V3.0 Expansion Board with PWM Cooling Fan & Safe Shutdown & DC 6V-30V Width Voltage Input for Raspberry Pi 4B/ 3B+/ 3B / 2B : Amazon.fr: Informatique
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power - Powering the Pi 4 - safe voltage levels and current requirements - Raspberry Pi Stack Exchange
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