With Xojo Dojo you get a simple code editor where you can write code using the Xojo programming language and a small set of additional commands for graphics, GPIO and some other things. It’s a great way to learn programming basics. Xojo Dojo includes several sample scripts to get you started.

For more information, check out the Xojo Dojo doc page.

Download the source from GitLab.

Add your #JustCode project to the week 11 forum conversation.

Download and check out earlier projects:

• Week 10: NetTank
• Week 9: Quote Web Service
• Week 8: JumpStart App Launcher
• Week 7: Pitch Tracker
• Week 6: Bubble Popper
• Week 5: Math Quiz
• Week 4: Mini-Golf ScoreKeeper
• Week 3: Dogs Up!
• Week 2: Password Generator
• Week 1: Color Picker

I decided what would work for me is to have demo app automatically launch when the Pi boots. This would allow me to demo the app and project anywhere just by plugging in the Pi. There are several ways that a Pi can automatically start an app. After doing a bit of Google research I decided on this approach:

1. Open the /etc/rc.local file (you’ll want to use sudo):

   sudo nano /etc/rc.local

2. Add lines to automatically start the app you want. My app was a console app that used GPIO, so I added these two lines:

   export WIRINGPI_GPIOMEM=1
   /home/pi/Documents/Xojo/LCDPanel &

For reference, this is my rc.local file contents:

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# Print the IP address
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
 printf "My IP address is %s\n" "$_IP"
fi

export WIRINGPI_GPIOMEM=1
/home/pi/Documents/Xojo/LCDPanel/LCDPanel &

exit 0

You can develop and build console and desktop apps for the Raspberry Pi using Xojo 2019r1 or later for free.

Download Xojo today and get started!

Fun times at XDC:

The Raspberry Pi is a complete computer —and a very cheap one!— with USB, HDMI, Ethernet and a GPIO that gives the access to design, create, and control a lot of things (think IoT). The perfect combination to create and deploy complete solutions with Xojo.

Nevertheless, you probably don’t want to use an exclusive display, keyboard and mouse just to control and interact with your Raspberry Pi. What about accessing it remotely via SSH and/or VNC? I bet this is the first thought you had, and here is a step-by-step guide to configure it so you can use your current display, keyboard and mouse from you main computer (the one you use to run the Xojo IDE) to control the Raspberry Pi.

First of all, while you can access your RPi via SSH, displaying your well trained Geek super powers, it is really more convenient to control it via the GUI, as you do your computer. For that you’ll need a VNC client app. There are a lot out there, but VNC Viewer is one that runs just fine and is available for the main platforms. Just download it, run the installer, follow the steps… and you will have completed the first part of the process.

In order to access the Raspberry Pi from the VNC client you will need to know what IP address is using the Pi. How to get that information? Easy! (This assumes that your local network uses DHCP to assign IP addresses, the most common scenario.)

If you use macOS, open the Terminal app (Applications > Terminal) and run the command:

$ ping 192.168.1.255

Changing the ‘192.168.1’ part of the IP address for the one of your local network. What is important here is the ‘255’ number, because this is the Broadcast IP address for your local network.

What happens when we ping the broadcast address? In brief: the packets are sent to every host of the local area so they can respond, giving their IP address in the process. The second piece of the needed information, the MAC Address, is automatically obtained from the hardware interface used by the device to reply the packet request.

Let the ping command do its work for several seconds and break the process pressing Control + C. (If you are using Linux, execute the command as ‘ping -b xxx.xxx.xxx.255‘.

The Mac Address is all the information needed by ARP: the inner cache table used by your router/switch device (and computer too), to link the unique hardware address (MAC Address) used by every device in the network with the IP address used by the device. So, executing the command:

$ arp -a

will give us a complete list of evey active IP address and the linked MAC Address. Knowing what IP addresses are already used by the devices of our network (computers, printers, cell phones, tablets…), it will be easy to identify the IP address assigned by DHCP to the Raspberry Pi.

So with these two pieces of information you can use the DHCP Binding feature of your home switch/router (all the home/SOHO routers have this feature), in order to assign the same IP address to the Raspberry PI every time you turn the device on and, connect it to the network. DHCP Binding looks for the MAC Address of the device… and matches it with the reserved IP address from the DHCP pool.

Starting the VNC Server on the Raspberry Pi

Don’t close the Terminal window yet, there are a couple of things that we need to do first. The first one is starting the VNC Server on the Raspberry Pi, so we can start new remote sessions from our client. For that we need to start an SSH session with:

$ ssh pi@raspberry-pi-address-here

Typing ‘raspberry’ as the password when requested. (‘pi’ and ‘raspbery’ are the user and password configured by default on every Raspberry Pi out there.)

Once started the SSH session, type the following:

pi@raspberrypi:~$ sudo raspi-config

This will open the Configuration Tool. Use the cursor keys to choose the ‘Advanced Options’ entry and press the Return key to advance to a new screen with options. Select the VNC entry (A5) and press the Return key again. Finally, make sure that VNC Server is enabled or enable it if not. Lastly, select the <Finish> option to exit the Configuration Tool.

Adjusting the Display Resolution used by VNC

Great, we have the IP address used by the Raspberry Pi, and the VNC Server enabled so we can start a VNC Client session… just to discover that it shows an endemic resolution of 800 x 600 pixels on our full-fledged Full HD display. Not the most productive thing we can expect.

Time to return to our Terminal windows, where the SSH session is still open (or start a new one if not). This time, we will edit the configuration file to instruct the Raspberry Pi to use a better fixed display resolution. For that, type the command:

pi@raspberrypi:~$ sudo nano /boot/config.txt

Go to the end of the opened file and write these lines:

 hdmi_force_hotplug=1
 hdmi_ignore_edid=0xa5000080
 hdmi_group=2
 hdmi_mode=51

In this case we are telling the Raspberry Pi to use a resolution of 1.600 x 1.200 pixels, but you can choose other changing the ‘hdmi_mode’ option to anyone of the settings you can find in this support page of Raspberry Pi.

Save the changes and exit from the Nano editor, and reboot the Raspberry Pi so the changes take effect:

 pi@raspberrypi:~$ sudo su
 pi@raspberrypi:~$ reboot

Ready! From now on, you can remotely access your Raspberry Pi via VNC and SSH.

You can watch the video (in Spanish only) that talks you though this example.

Javier Rodri­guez has been the Xojo Spanish Evangelist since 2008, he’s also a Developer, Consultant and Trainer who has used Xojo since 1998. He is in charge of AprendeXojo.com and the developer behind the GuancheMOS plug-in for Xojo Developers and the Snippery app, among others.

*Read this post in Spanish

The Xojo programming language is fully object-oriented and uses an object model that is quite similar to VB, Java and C#. If you are used those languages at all, you’ll be right at home with Xojo.

Available since 1998, Xojo was one of the first languages to use Automatic Reference Counting (ARC), something that other languages such as Swift and Objective-C now use. Xojo is type-safe and fully object-oriented making it easy to learn and use, but it also has advanced features such as namespaces, extension methods, exception handling, introspection, delegates and more.

You can code on any platform

Xojo itself runs on Windows, OS X and Linux. So you can choose to do your programming on the platform you prefer. And unlike some other languages, you do this using a powerful and friendly IDE, not a text editor.

Xojo is a great learning language

Xojo strives to keep things simple, making it a great first programming language. In fact, there is a free book, Introduction to Programming with Xojo, to help you get started.

In addition to the book, Xojo ships with over 300 example projects, plus there are tutorials, videos and thousands of pages of documentation at the Xojo Dev Center.

Xojo is updated regularly

Xojo is generally updated quarterly with a variety of new features and bug fixes. Since 2014, major new features include iOS apps, Raspberry Pi apps, 64-bit apps and HiDPI (retina) support.

Lots of open-source projects

Xojo is free to use and in addition to the over 300 example projects included with it, Xojo developers have created many open-source projects that you can use with your own Xojo projects to add features or to learn from. Check out this list of open-source projects and others on GitHub.

Xojo makes All The Things

The bottom line is that as a cross-platform and multi-plaform programming tool, Xojo makes All the Things.

Xojo can make desktop and console apps for Windows, OS X and Linux. Xojo can make desktop and console apps for Raspberry Pi that interface with the GPIO port. Xojo makes web apps. Xojo makes iOS apps. All Xojo apps are native, compiled apps that use standard OS controls.

Try Xojo today for free to see how easy it is to make your own apps!

I am pleased to announce some updates to our GPIO project to make it even easier to use more types of hardware in your Raspberry Pi projects.

The Xojo GPIO library, version 1.5 is now available on GitHub and adds support for these hardware features:

• LCD character display
• Servo motor
• RGB LED
• Buzzer tunes

Some of these features were enabled by adding support for the wiringPi SoftPwm and SoftTone methods. In addition, Servo, LCD and RGBLED can be controlled using simple classes.

Head on over to the Xojo Dev Center for tutorials on how to these new features:

• LCD character display
• Controlling a Servo
• Using an RGB LED
• Using a Buzzer

Why work with a simple text editor and the command line when you can instead use a fully-feature IDE to create Raspberry Pi apps for your projects?

Like the rest of the Xojo GPIO library, these new features work similarly to features in commonly used Python GPIO libraries. Now you should be able to readily adapt Python code to work in Xojo so you can more easily create great Raspberry Pi projects!

These projects are all free and show you how to hook up a variety of sensors to your Pi and then interface with them using Xojo. Topics include:

• Motion Sensor
• Relay Board
• Flame Sensor
• Humidity and Temperature Sensors
• Infrared Sensor
• Ultrasonic Sensor

These projects make use of the open source GPIO module that is included with Xojo and available on GitHub.

You can view all the Pi Projects here:

Xojo Pi/GPIO Projects

You can develop and build console and desktop apps for the Raspberry Pi using Xojo 2019r1 or later for free.

Download Xojo today and get started!

The answer is to use the GPIO module that is included with Xojo in conjunction with the wiringPi library. And now this module is also available on GitHub:

Xojo GPIO Module

This module is used for our two Raspberry Pi projects: Blinking LED and Button LED. They are also used by the Einhugur Pi projects for Xojo.

I encourage all you Raspberry Pi experts to clone the GPIO project on GitHub and push up any enhancements you come up with.