I recently needed to measure how different materials affect light transmission for a gardening project. I decided this was the perfect opportunity to try out the new logic level converter to run both a 5v LCD and a 3.3v light sensor on a single i2c bus. I used the following parts in this project:
- Arduino Uno
- TSL2561 Digital Light Sensor
- 4-channel I2C Safe Bi-directional Logic Level Converter
- 16×2 LCD
- LCD I2C Backpack
Optional (but definitely helps keep everything tidy):
First up is wiring power to the breadboard from the Arduino. I decided to keep the left side for 3.3v and the right side for 5v.
- Breadboard right ground bus – black wire – Arduino ground pin
- Breadboard right positive bus (5v bus) – red wire – Arduino 5v pin
- Breadboard left ground bus – black wire – Breadboard right ground bus
- Breadboard left positive bus (3.3v bus) – yellow wire – Arduino 3.3v pin
The next step is adding the logic level converter to the breadboard. It straddles the center notch like a DIP (but takes one additional column). I placed it toward the top of the breadboard to leave plenty of space for the light sensor to be added later.
- Level converter LV pin – yellow wire – Breadboard 3.3v bus
- Level converter HV pin – red wire – Breadboard 5v bus
- Level converter left GND pin – black wire – Breadboard left ground bus
- Level converter right GND pin – black wire – Breadboard right ground bus
- Level converter B1 pin – green wire – Arduino analog pin 5 (i2c clock line)
- Level converter B2 pin – blue wire – Arduino analog pin 4 (i2c data line)
For more detail: Light Meter Using I2C Level Converter, LCD, and TSL2561
