Electronic Shelf Label based on Digital 1-to-8 I2C Multiplexer

Sometimes I encounter with a problem like this, I just found the sensor I needed, and now I want to wire up several same sensors to the I2C port of my controller, but they have fixed i2c address which means that I can not directly use them on the same i2c port.

What should I do? Now a Digital 1-to-8 I2C Multiplexer made by DFRobot easily solved my problem.

It is said that we can hook up 8 multiplexers on address 0x70~0x77 to control 64 same-address devices.

So powerful! Today I am gonna make an electronic shelf label with this i2c multiplexer.

Digital 1-to-8 I2C Multiplexer

These are five different electronic shelf labels made by DFRobot (the i2c address of the five screen is 0×73)

The materials you may need:

• Gravity: Digital 1-to-8 I2C Multiplexer
• Gravity: I2C 16x2 Arduino LCD with RGB Font Display (Black)
• Gravity: I2C 16x2 Arduino LCD with RGB Backlight Display
• Gravity: I2C LCD1602 Arduino LCD Display Module (Blue)
• Gravity: I2C LCD1602 Arduino LCD Display Module (Gray)
• Gravity: I2C LCD1602 Arduino LCD Display Module (Green)
• DFRduino UNO R3 - Arduino Compatible
• Gravity IO Expansion Shield for Arduino V7.1
• 7.4 V 2500mA Lithium Battery(with charge-discharge protection board)

It’s quite a simple operation. The most important step is to print out the case, and then mount a clip made of two torsion springs on the case, so you can clip it to the shelf easily.

The following two displays are my favorite.

The usage of I2C Multiplexer is similar to the control of faucet diverter. A main I2C pipe is connected to DFRduino UNO R3, and then the multiplexer divides the main pipe into 8 branches of pipes and faucets. During the use process, which faucet is on, the I2C communication will be connected to the corresponding device. But we cannot turn on two faucets at the same time. If we did so, the first one we turn on is regarded to be invalid by default.