The scenario
An embedded developer plans an ESP32-based smart home controller that drives a relay for a lamp and interfaces with a touch screen over I2C.
What is in this drawing
Read the decisions behind it.
01
Use a 5V USB supply with LDO to power the ESP32 at 3.3V and I2C pullups for the touch screen
02
Use an opto-isolated relay module driven by GPIO to switch a separate 12V lamp load
03
Add flyback diode across relay coil and filter capacitors on supply rails
When designing or documenting ESP32 home automation nodes with relay outputs and TFT touch interfaces.
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