GPIO with bash

[atomic3]

I'd like to use bash to control the gpio pins on the pi.

I've found a couple of examples to change the state of the pins and read values from them.

I was wondering if it would be possible to hook up and IR Receiver and try to read the output with just bash.

Also generating PWM with bash would involve alternating on/off with sleep intervals correct?

Thanks.

[joan]

I was wondering if it would be possible to hook up and IR Receiver and try to read the output with just bash.

You could certainly try.

You won't get any useful results though. The pulses are of the order of 100s of microseconds. I don't see how you'd time them in bash.

Also generating PWM with bash would involve alternating on/off with sleep intervals correct?

Yes, that's what PWM does. Don't expect great speeds though.

See http://codeandlife.com/2012/07/03/bench ... pio-speed/

[pluggy]

I use GPIO from BASH, using Gordons WiringPi Library. https://projects.drogon.net/raspberry-pi/wiringpi/ . You can do much direct from BASH using the gpio utility (including using PWM) , but its not too difficult to write code using his library to do timing critical and 'messy' bits that BASH doesn't do too well. Gordon does a fair amount of posting on this forum.

[atomic3]

Thanks for your replies.

I just don't like to install a lot of stuff and really wanted to just use bare Bash, I guess I'll get wiringPI a try.

[RPiJunior]

Run

Code: Select all

echo [pin number] > /sys/class/gpio/export

replacing [pin number] appropriately.

For output,

Code: Select all

echo out > /sys/class/gpio/gpio[pin number]/direction

replacing [pin number] appropriately.

For input,

Code: Select all

echo in > /sys/class/gpio/gpio[pin number]/direction

replacing [pin number] appropriately.

Code: Select all

/sys/class/gpio/gpio[pin number]/value

replacing [pin number] appropriately, is your man.

Run

Code: Select all

echo [pin number] > /sys/class/gpio/export

replacing [pin number] appropriately, to clean up.