GPIO pins

Gersch

Hello.
I wanted to ask if it is possible to use the GPIO pins of the Raspberry? I would like to build a car radio. If the input is low, turn off the pi. With a time relay, I would then take the voltage from the pi. When the vehicle is started again, the pi starts again.

Thx Gersch

SanderK

In short: yes, it is.

IKS

Hi Gersch, yes, it is possible. Right now it is possible just the same way you would do it in Linux (via sysfs). We are also planning on adding proper Java API for that, but it may take us a while until it is ready.

David

Hi,
did you make any progress by adding a Java API?

IKS

Not yet, but the next release will include /dev/gpiomem, which you can use for example with wiringPi.

David

Thanks a lot.

FelipeTraesel

Hi Kalkov,
Does it allow SPI at the moment? How can we access it?

IKS

It should be enabled by default and accessible in the standard RPi way as you would do it in Linux.

FelipeTraesel

Thanks Kalkov
Also, is there any library for SPI like BCM2835? I read upwards that wiringpi will be available. Is there some trial version yet?

FelipeTraesel

Sorry, I'll be more direct: I need to access SPI to comunicate with a MCP2515 can controller.
Like in raspbian, we do $ sudo apt-get install can-utils to download the can library.
Is there some workaround to access SPI like this?

IKS

No, there is nothing Android-specific yet. But there exist seevral WiringPi-for-Android projects. For example: https://github.com/joerg65/Example-wiringPi

FelipeTraesel

Hello Kalkov,

I've tried wiringPi for accessing SPI. I get Unable to open SPI device: Permission denied.
Looking for it I found in ODROID something about compile a custom kernel. Is that so or for the raspi there is something else, let's say less complicated.
Thanks, Felipe

IKS

I don't think you need to (re-)compile anything, just apply the correct configuration (like setting permissions). As you might understand, we can't provide project-specific support here. Please feel free to open a new question in the "Projects" category with a description of your goals and I am sure someone will help you finding the answer.

AryaStuti

Hello,
I am working on project in college and don't have much knowledge about emteria. I am trying to make alarming circuit with pi3 for security of room. And in initial stage, I am not able to connect with gpio input and output. Emteria has gpio support or not?
Would I be able to complete my alarming project?
Anyone please help!

IKS

@AryaStuti, you don't need any extra knowledge about emteria.OS. It should be sufficient be know how it is done in Linux: https://www.raspberrypi.org/forums/viewtopic.php?t=193096

ulfdogg

i am sorry. I do not understand this. I want to do a similar thing in my car. i have a push button, which i used on raspbian to shutdown the system. I installed it on the GPIO3 so that it would be powerd on. This works on Android aswell. The shutdown on raspbian worked with a python script. I changed to android because I want to test spotify offline, Headunit reloaded etc. Could you please help me. I looked on google, but I am not really good at this kind of thing. Thank you

IKS

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