Tag: part4

Raspberry Pi – Part IV – Simple Wiring Test

I am plugging away working with my Pi. I went back to the Ada Fruit Site, and started working on one of the tutorials from the part I purchased – https://www.adafruit.com/products/2125 I want to be able to demonstrate a simple wiring with my Pi works.

I selected Email Notifier. I read through it, and realized I needed to convert it to work for the B+ model. The pi4j website has a nice diagram for the pins http://pi4j.com/images/j8header-b-plus-large.png and I simplified the test a bit.

	#!/usr/bin/env python

	#REF https://learn.adafruit.com/raspberry-pi-e-mail-notifier-using-leds/python-script
	import RPi.GPIO as GPIO
	import time

	GPIO.setwarnings(True)
	GPIO.setmode(GPIO.BCM)
	GREEN_LED = 23
	GPIO.setup(GREEN_LED, GPIO.OUT)

	def loop():
	GPIO.output(GREEN_LED, True)
	time.sleep(100)

	if __name__ == '__main__':
	try:
	print 'Press Ctrl-C to quit.'
	while True:
	loop()

	finally:
	GPIO.cleanup()

view raw testPi.py hosted with

by GitHub

I launched the simple python file

pi@seconds ~ $ sudo python testPi.py

Pi with a Green Light - Using Python — Pi with a Green Light – Using Python

I added the pi4j dependency to my maven pom

<dependency>
    <groupId>com.pi4j</groupId>
    <artifactId>pi4j-core</artifactId>
   <version>1.0</version>
</dependency>

I create a servlet which replicated the same code from before (GPIO).

	package bastide.pi.bbq;

	import java.io.IOException;

	import javax.servlet.ServletException;
	import javax.servlet.annotation.WebServlet;
	import javax.servlet.http.HttpServlet;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;

	import com.pi4j.io.gpio.GpioController;
	import com.pi4j.io.gpio.GpioFactory;
	import com.pi4j.io.gpio.GpioPinDigitalOutput;
	import com.pi4j.io.gpio.PinMode;
	import com.pi4j.io.gpio.PinState;
	import com.pi4j.io.gpio.RaspiPin;

	/**
	* Servlet implementation class Control
	*/
	@WebServlet("/Control")
	public class Control extends HttpServlet {
	private static final long serialVersionUID = 1L;

	/**
	* @see HttpServlet#HttpServlet()
	*/
	public Control() {
	super();
	// TODO Auto-generated constructor stub
	}

	/**
	* simple processing of the status flag for the servlet
	* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	*/
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	String param = request.getParameter("status");

	if(param!=null && !param.isEmpty()){
	boolean status = Boolean.parseBoolean(param);

	final GpioController gpio = GpioFactory.getInstance();
	// RaspiPin.GPIO_23);

	final GpioPinDigitalOutput pin = gpio.provisionDigitalOutputPin(RaspiPin.GPIO_23, "MyLED", PinState.HIGH);

	gpio.setMode(PinMode.DIGITAL_OUTPUT, pin);

	System.out.println("--> GPIO state should be: " + status);
	}
	}

	}

view raw Control.java hosted with

by GitHub

I copied the war file to the local webapp directory, and restarted jetty

pi@seconds /opt/jetty/web/bbq/webapps $ sudo cp ~/pi.webapp.war ./
pi@seconds /opt/jetty/web/bbq/webapps $ sudo chown jetty:jetty pi.webapp.war
pi@seconds /opt/jetty/web/bbq/webapps $ sudo /etc/init.d/jetty restart

Refer to https://wiki.eclipse.org/Jetty/Howto/Deploy_Web_Applications and I did have to add –module=jsp to the start.ini for my web configuration.

I hit the servlet – http://192.168.1.200/pi.webapp/Control?status=true

Which makes sense, since “Software using the Pi4J library must be run with ROOT level permissions.” (actually it doesn’t since I am running as root)…

Issues remain. I’ll tackle them on a different day … Part 5 …

2015-04-23