KY-051

This level shifter converts digital signals from one voltage to another up or down. There are 4 available channels that can be converted.

Nowadays there are a number of microcontroller systems that operate in different voltage ranges: For example, the inputs and outputs of older systems such as Arduino, based on an Atmega controller, work with 5V level, the newer Raspberry-Pi computers based on an ARM controller, with a voltage level of 3.3V.

This is due to the fact that communication between microcontrollers used to have to work with higher voltages, since the input stages have a greater distance between the voltage level for [Digital ON] = 5V and for [Digital OFF] due to noise / interference in the lines = 0V - In the course of modernization, the input / output stages of the controllers have become significantly better and nowadays one would like to keep the voltage used as low as possible so that heat development and power consumption decrease. The use of 1.8V systems is not uncommon these days.

However, if you want to communicate between two systems with two different voltage levels (like the Arduino -> Raspberry Pi example below), the voltage level must be "shifted" - if this is not done, the system with the lower voltage level must transfer the excess voltage to the Input levels "consume in heat". Depending on the system, this can lead to permanent damage to the system.

Pin assignment

The pin assignment is printed on the module board.

The signals at the inputs / outputs A1-A4 and B1-B4 are shifted to the respective voltage level (VCCa -> A1-A4 | VCCb -> B1-B4)

Example:

Arduino output -> Digital [ON] = 5V @ B1 >>>>>>> 3.3V @ A1 -> Raspberry Pi input

Additional software or code is not required for operation; the module works autonomously.

Please note that VCCb must be greater than / equal to VCCa (example VCCb = 5V - VCCa = 3.3V)

Example connection assignment between Arduino and Raspberry Pi:

Pin assignment Arduino:

Arduino Sensor
5V Vccb
Pin 3 B1
Pin 4 B2
Pin 5 B3
Pin 6 B4
Mass GND

Pin assignment Raspberry Pi

Raspberry Pi Sensor
3.3V [pin 1] Vcca
GPIO 18 [pin 12] A1
GPIO 3 / SCL [Pin 5] A2
GPIO 2 / SDA [Pin 3] A3
GPIO 11 [pin 8] A4
Ground [pin 6] GND

Please make sure that both systems are connected to the same GND (ground) - OE does not have to be connected with this module.

Example connection assignment between Arduino and Micro:Bit:

Pin assignment Arduino:

Arduino Sensor
5V Vccb
Pin 3 B1
Pin 4 B2
Pin 5 B3
Pin 6 B4
Mass GND

Pin assignment Raspberry Pi

Micro: bit Sensor
3.3V [pin 3V] Vcca
P0 [pin 0] A1
P1 [pin 1] A2
P2 [pin 2] A3
P8 [pin 8] A4
Ground [pin GND] GND

Please make sure that both systems are connected to the same GND (ground) - OE does not have to be connected to this module. A breakout board is recommended to connect the Micro: Bit.