I2C LCD Front Panel with rotary encoder + RGB LED

Name: I2C LCD Front Panel with rotary encoder + RGB LED
SKU: 33027
Price: 19.99 USD
Availability: InStock

A I2C/Qwiic/STEMMA QT based front panel containing a 2x16 LCD display, a rotary encoder and a RGB led. Supports 3.3V and 5V operation

Designed by Kiesel Electronics in Germany

I2C LCD Front Panel with rotary encoder + RGB LED 1

I2C LCD Front Panel with rotary encoder + RGB LED 2

I2C LCD Front Panel with rotary encoder + RGB LED 3

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A I2C/Qwiic/STEMMA QT based front panel containing a 2x16 LCD display, a rotary encoder and a RGB led. Supports 3.3V and 5V operation

What is it? The module is an open source, I2C based LCD front panel with a 2x16 HD44780 LCD display, a rotary encoder and a RGB LED. A comprehensive user interface can be implemented without the need…

What is it?

The module is an open source, I2C based LCD front panel with a 2x16 HD44780 LCD display, a rotary encoder and a RGB LED. A comprehensive user interface can be implemented without the need for additional components. The unit contains two Qwiic/STEMMA QT connectors as well as a footprint for a pin-header for easy connectivity. The module runs on 3.3V or 5V (the display contrast has to be adjusted when changing the supply voltage). The software and the schematic are available under GPL-3.0 license

Why did you make it?

The module simplifies integration of a user interface into a project significantly. A demo application demonstrates how a menu structure can be implemented easily.

The panel is designed for easy integration. The four studs around the display can be used to attach it to the front panel of a case.

Module construction

There are two I2c devices on the PCB. The PCF8574 is attached to the LCD display. Since this is a very common chip for attaching LCD displays via an I2C bus, many available drivers support this combination. The default I2C address of the LCD IO expander is 0x27. It can be changed with the help of three solder bridges. Please see the PCF8574 datasheet for details.

There is also a ATTiny414 on the board. This uC comes preprogrammed. It handles the rotary encoder and the RGB LED. Also, it is responsible for generating a negative power rail to allow proper LCD contrast adjustment with 3.3V supply voltage. The source code for the microcontroller is available on Github. For programming a new firmware version an debugger or programmer with support of UPDI is needed. The default I2C address of the ATTiny is 0x34. When the solder bridge is closed; the address is changed to 0x54.

Rotary Encoder

The micro-controller keeps two variables concerning the rotary encoder. The first variable reflects the status of the rotary action. When the encoder is turned clockwise, the variable is increased, if it is turned counterclockwise the variable is decreased. The second variable reflects the button presses on the encoder. With each button press, the value is increased. The values can be read via I2C. A I2C read with 3 bytes request will be answered with the values of both variables. Please see the documentation and the demo code on Github for more details.