Build your module

If you selected the components what you will use, it's time to assemble. The PINs in ESP can be changed if you compile the firmware yourself.

TLDR:

• ESP Serial RX (for GPS) PIN 6
• I2C SCL -> ESP PIN 4
• I2C SDA -> ESP PIN 5

For H4 I2C: (this is the preferred method!)

• GND -> GND
• SCL from H4 goes -> GPIO 10 on ESP
• SDA from H4 goes -> GPIO 11 on ESP

Don't use USB + I2C at the same time, it won't help in anything, the PP will receive the same data but duplicated.

Serial GPS module

Line the GND to the module's GND, and 3.3V or 5V according to your module to the VCC of your module. The GPS TX pin should be wired to ESP's PIN 6. GPS RX not used.

I2C devices

Line the GND to the module's GND, and 3.3V or 5V according to your module to the VCC of your module. Wire the module's SCL pin to ESP PIN 4, and SDA pin to ESP PIN 5.

With I2C devices you must use the same SCL, SDA pins for all devices you want to connect.

Example of a built module