Raspberry GPIO's Setup

ASL GPIO wiki

Lets consider we are going to use

GPIO 17 (Pin 11) for COS input

GPIO 27 (Pin 13) for PTT Output

Install wiringpi

sudo apt-get install git-core
sudo git clone https://github.com/WiringPi/WiringPi.git /opt/wiringpi
cd /opt/wiringpi
sudo ./build

Create an initialization file

Create the following file using nano:

sudo nano /usr/local/sbin/Init-GPIO.sh

Add the following code to the file

#!/bin/bash
#script name - Init_GPIO
# COS Input
gpio -g mode 17 in # makes gpio 17 pin 11 on Raspberry pi 2/3 as input
gpio -g mode 17 up # activates pull-up
# PTT pin (Output)
gpio -g mode 27 out # makes gpio 27 pin 13 as output
gpio -g write 27 0 # Default to 0/Off

After making your changes type <CTRL> + <X> and then type <Y> followed by <Enter>. You will be back to the previous menu and choose <Back>.

Create the COS monitoring script

Create the following file using nano:

sudo nano /usr/local/sbin/COS-wfi.sh

#!/bin/bash
gpio -g mode 17 in
gpio -g mode 17 up
while [ 1=1 ]
do
  # wait int pin to go low
  gpio -g wfi 17 both
    COS=$(gpio -g read 17)
    if [ "$COS" = "0" ]; then
      gpio -g write 27 1
      echo COS GPIO low/closed
    else
      gpio -g write 27 0
      echo COS GPIO high/open
    fi
done

After making your changes type <CTRL> + <X> and then type <Y> followed by <Enter>. You will be back to the previous menu and choose <Back>.

Create Event files

now create the following file using nano:

sudo nano /usr/local/sbin/PTT-GPIO-high.sh

Add the following lines to the file, in this example I am using GPIO 27 which is assigned to pin 13 on a Raspberry Pi Model 2/3.

#!/bin/bash
gpio -g write 27 1

After making your changes type <CTRL> + <X> and then type <Y> followed by <Enter>. You will be back to the previous menu and choose <Back>.

Next create the following file using nano:

sudo nano /usr/local/sbin/PTT-GPIO-low.sh

Add the following lines to the file, in this example I am using GPIO 27 which is assigned to pin 13 on a Raspberry Pi Model 2/3.

#!/bin/bash
gpio -g write 27 0

After making your changes type <CTRL> + <X> and then type <Y> followed by <Enter>. You will be back to the previous menu and choose <Back>.

Make the Init-GPIO and COS-wfi.sh scripts run at startup

you have to add a line to the rc.local file.

sudo nano /etc/rc.local

Before the exit 0 line you have to add:

/usr/local/sbin/Init-GPIO.sh
/usr/local/sbin/COS-wfi.sh

After making your changes type <CTRL> + <X> and then type <Y> followed by <Enter>. You will be back to the previous menu and choose <Back>.

Edit rpt.conf file

Now use nano to edit your rpt.conf file:

sudo nano /etc/asterisk/rpt.conf

On your node number stanza, i.e. [12345] add the following line:

events=events12345;

Then at the end of the file add the following stanza:

[events12345]
sudo /usr/local/sbin/PTT-GPIO-high.sh = S|T|RPT_TXKEYED;
sudo /usr/local/sbin/PTT-GPIO-low.sh = S|F|RPT_TXKEYED;

After making your changes type <CTRL> + <X> and then type <Y> followed by <Enter>. You will be back to the previous menu and choose <Back>.

sudo chmod +x Init-GPIO.sh
sudo chmod +x PTT-GPIO-high.sh
sudo chmod +x PTT-GPIO-low.sh