Logic Level converter makes it possible to connect 3.3V (or even lower voltage sensors) to 5V micro controllers like the Raspberry Pi. With this module you can easily connect different logic voltage levels together for bi-directional communication on up to 8 channels, allowing you to use low-voltage sensors with a 5V micro-controller.
Instructions: (Take 3.3V, 5V conversion for example)
VCCA connects to Raspberry Pi 3.3V power supply
VCCB connects to 5V power supply(It can be external 5V power supply)
GND connects to negative pole, two power supplies common-grounded
Ax inputs Raspberry Pi 3.3V TTL level, Bx outputs 5V sensor module TTL level
Bx inputs 5V electronic module TTL level, Ax outputs Raspberry Pi 3.3V TTL level
1 x Conversion Module