Raspberry pi 4 controle GPIO with java

3
votes

I want to controle a 16*2 lcd display on my raspberry pi4 with java. The problem is that Pi4J - the solution to modify the gpios with java is not updated to pi4. Is there another solution? This error occures when I start the programm:

pi@raspberrypi:~/desktop/gpio $ sudo ./start.sh

<--Pi4J--> GPIO Control Example ... started. Maista Unable to determine hardware version. I see: Hardware : BCM2711 ,

  • expecting BCM2708 or BCM2709. If this is a genuine Raspberry Pi then please report this to [email protected]. If this is not a Raspberry Pi then you are on your own as wiringPi is designed to support the Raspberry Pi ONLY.
3
javaraspberry-pigpioraspberry-pi4
Did you contact [email protected]? Or look at the pi4j web site? Seems like the authors would be best equipped to talk about their code. – user13784117
If you don't find what you need, you should look at raspberrypi.stackexchange.com. – NomadMaker
@user13784117, the WiringPi dev has thrown the towel. Contacting him will likely not achieve anything. – user7655213
The promise of open source is that if the author won't fix it, you can do it yourself :-) – user13784117
For most of the LCDs (often hd44780) there is a driver in the kernel. Use it and your life will be much easier. – 0andriy

3 Answers

5
votes

Pi4J uses WiringPi to control the GPIOs. So please update it to version 2.52 as this one supports the Raspberry Pi 4, see http://wiringpi.com/wiringpi-updated-to-2-52-for-the-raspberry-pi-4b/

$ gpio -v
gpio version: 2.50
$ cd /tmp
$ wget https://project-downloads.drogon.net/wiringpi-latest.deb
$ sudo dpkg -i wiringpi-latest.deb
$ gpio -v
gpio version: 2.52

You can find a full java+pi4j+lcd example on my blog on https://webtechie.be/post/2020-01-26-openweathermap-forecast-on-lcd-with-raspberry-pi-java-and-pi4j/

0
votes

I found out the reason it was not working for me, is that sudo dpkg -i wiringpi-latest.deb installs gpio in /usr/bin/gpio but there was another gpio file in /usr/local/bin/gpio which was taking precedence. You can find if this is the case for you by running which gpio.

I renamed the old file from gpio to gpio.old (I did not want to delete it, just in case) and executed sudo dpkg -i wiringpi-latest.deb again. Now when I run which gpio I find the correct executable.

-1
votes

I found this that can help you. It seems easy to understand, you just need to change some xml files.