Using Board Info

GITHUB Sources of BoardInfoHelper.java and the data model: pi4j-v2/pi4j-core/src/main/java/com/pi4j/boardinfo/util/BoardInfoHelper.java

Since V2.6.0, the new class BoardInfoHelper provides the following info:

  • Type of Raspberry Pi board as a BoardInfo object.
  • If the system uses a RP1 chip with usesRP1() (Raspberry Pi 5 only at this moment).
  • If the system is 32-bit or 64-bit with is32bit() and is64bit().
  • The amount of memory available and used by the JVM as a JvmMemory object.
  • Info about volt, temperature, etc. as a BoardReading object.

The board info is used in some of the plugins to set the correct priority, based on the use of a Raspberry Pi 5 (with RP1) versus earlier board (without RP1).

How the Board Model is Detected

Previous Method (< 2.7.1 version)

In earlier versions, the board model was determined by reading the board version number from the /proc/cpuinfo file using shell commands:

$ cat /proc/cpuinfo | grep 'Revision' | awk '{print $3}'

Updated Method (>= 2.7.1 version)

Starting with version 2.7.1, the board version number is determined programmatically in Java using the CpuInfoReader class. This method reads and processes the /proc/cpuinfo file to extract the CPU revision.

For instance, for a Raspberry Pi Compute 4, multiple version numbers are possible:

COMPUTE_4("Compute Module 4", STACK_ON_COMPUTER,
        Arrays.asList("a03140", "b03140", "c03140", "d03140", "a03141", "b03141", "c03141", "d03141"),
        ...)

Demo Use on api.pi4j.com

The new BoardInfoHelper class and the related enums and methods are used as the basis for the website api.pi4j.com that visualizes all the info defined inside the library, like board info, header pins, type of pins, etc. This website runs on a Raspberry Pi board, so the System Information screen show the info about that board using this new class.

List of boards defined in the library

List of boards defined in the library

System Information of the Raspberry Pi running the website

System Information of the Raspberry Pi running the website

Example Code

var console = new Console();
var pi4j = Pi4J.newAutoContext();

// ------------------------------------------------------------
// Output Pi4J Board information
// ------------------------------------------------------------
// When the Pi4J Context is initialized, a board detection is 
// performed. You can use this info in case you need board-specific
// functionality.
// OPTIONAL
console.println("Board model: " + pi4j.boardInfo().getBoardModel().getLabel());
console.println("Operating system: " + pi4j.boardInfo().getOperatingSystem());
console.println("Java versions: " + pi4j.boardInfo().getJavaInfo());
// This info is also available directly from the BoardInfoHelper, 
// and with some additional realtime data.
console.println("Board model: " + BoardInfoHelper.current().getBoardModel().getLabel());
console.println("Raspberry Pi model with RP1 chip (Raspberry Pi 5): " + BoardInfoHelper.usesRP1());
console.println("OS is 64-bit: " + BoardInfoHelper.is64bit());
console.println("JVM memory used (MB): " + BoardInfoHelper.getJvmMemory().getUsedInMb());
console.println("Board temperature (°C): " + BoardInfoHelper.getBoardReading().getTemperatureInCelsius());

Example Output

[main] INFO com.pi4j.util.Console - Board model: Raspberry Pi 4 Model B
[main] INFO com.pi4j.util.Console - Operating system: Name: Linux, version: 6.1.21-v8+, architecture: aarch64
[main] INFO com.pi4j.util.Console - Java versions: Version: 22, runtime: 22+36, vendor: Azul Systems, Inc., vendor version: Zulu22.28+91-CA


[main] INFO com.pi4j.util.Console - Board model: Raspberry Pi 4 Model B
[main] INFO com.pi4j.util.Console - Raspberry Pi model with RP1 chip (Raspberry Pi 5): false
[main] INFO com.pi4j.util.Console - OS is 64-bit: true
[main] INFO com.pi4j.util.Console - JVM memory used (MB): 10.910163879394531
[main] INFO com.pi4j.util.Console - Board temperature (°C): 61.3