Electronic – Powering up an ESP32 with IO extender (MCP23017) and two of 8 channel relays from an external 5 V, 10 A power supply

esp32esp8266power supply

I'm working on a project that needs an ESP32 board, IO extender (MCP23017), two of 8 channel relays and some sensors, I've powered up all of the parts from a stable 5 V, 10 A power supply as shown in this block diagram:

the block diagram of the parts

Added: More detailed wiring diagram:

diagram showing external connections to the ESP32 board

After connecting all the parts to the external power supply, the ESP32 gets too hot and then it burns after 10 seconds.

Could you please correct my connections, if there are any mistakes?

The sensors are:

  • 2 DHT22

  • 2 MQ135

  • 2 Magnetic switches

  • Ultrasonic

Thanks for your time.

Update: The connections were correct. I've just added voltage dividers and it worked correctly.

diagram showing external connections to the ESP32 board, with added voltage-dividers

Best Answer

The ESP32 runs of 3.3V (I found a schematic which I hope is the correct one).

I do not have schematics of the other parts but I notice that everything runs of 5V. I suggest you check:

  1. If the I/O of all connected ports are 3V3. or
  2. If the ESP32 has 5V tolerant ports.

If not you are connecting 5V I/O ports to a 3V3 processor. That might explain why it gets hot.

A more dangerous way is to connect things one-by-one and check which one makes it get hot. (I would normally not recommended that but it is a quick-and-dirty way to narrow done where the problem is)

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