You may have used an electronic device with a small Liquid Crystal Display (LCD) which has a textual hierarchical menu system for setting device configuration parameters. If you have tried writing menu code for your Arduino projects, you will recognise the challenge in developing a generic menu system for an open prototyping platform. This is because there are many input and display devices available, and a generic menu system must be independent of whichever input and display devices you wish to use. With our Arduino menu library, this independence is achieved by having the menu manager code use callback methods for handling user input and rendering the menu display.
To keep things simple, all coding examples have been targeted to work with an R3 Arduino Uno/Leonardo/Mega2560, and an LCD keypad shield similar to one illustrated above. There are numerous manufacturers of LCD keypad shields that have the same or similar pin connections, and you must ensure that the sample menu code uses the pin connections that are right for your shield. If the keypad buttons of your shield give different analog readings, you’ll need to make changes to file LcdKeypad.h. Bear in mind that the analog readings are not always consistent, which can lead to the occasional misreporting of a button press. Once you become familiar with the menu library, adapting it for use with other input and display devices should be straight-forward.
With numerous menu libraries readily available, why use this Arduino menu library? We think it is easier to use thanks to our online code generator, and has better memory efficiency with its use of PROGMEM. Watch the short video clip below and see for yourself.
Follow a Few Simple Steps to Build a LCD Menu
Step 1 – Download LCD Menu Sample Project
Download the following Arduino sample project for testing out your menus. You’ll need to find and install the TimerOne library for the code to compile.
Step 2 – Use Online Menu Builder
Our free online menu builder allows you to paste in a simple Xml representation of your menu, from which the Arduino menu source code is generated automatically. Use the sample Xml included in the project you just downloaded to get started.
Step 3 – Build Arduino Project
Copy the generated code and paste in to MenuData.h file of your Arduino project, overwriting existing content. Build and upload your Arduino project.
Step 4 – Test Your Menu
After successfully uploading your Arduino project, test out your menu. Now that you have a menu in place, you can work on the main logic of your application. If you need to rework your menu in the future, the MenuData.h file has a copy of the xml that was used to generate it, which you can copy and paste in to the online menu builder.
Using Menus in Your Own Code
You can use the downloaded sample Arduino project as a starting point for your own coding requirements. You will need to write your own code in the body of method processMenuCommand(byte cmdId) to determine what must be done when a menu item is selected. The cmdId parameter is the Id you associate with a menu item in your menu Xml file. Callback method getNavAction() handles user input, and callback method refreshMenuDisplay(byte refreshMode) renders the menu. To work with other input and display devices you’ll need to re-write the code in these methods. Some LCD keypad shields are not suited for hardware PWM backlight control, and as such the coding example uses a soft PWM alternative.
LCD Countdown Timer with Menu System
The source code for an Arduino countdown timer with multiple profiles can be downloaded from the link below:
The Select button on the LCD shield starts/stops a timer, with a long press resetting the timer. A long press of Up enters the menu. Up/Down/Right buttons are for navigating the menu, and Select for choosing a menu item. When an item is selected, Up/Down are used for changing values. When the Reset menu item is displayed, a long press of Select loads default configuration values. Digital pin 2 is used for activating a beeper for the alarm. Examining the source should give you good insight for using the menu system in your own projects. If you find this Arduino menu library guide useful, please share it.