OpenVPN on a Raspberry Pi

Sorry if lately I'm publishing really few posts, but this year I've been quite busy planning my weddings, so I have almost no time for everything else...

Anyway in these days I created a simple VPN server on one of my Raspberry Pi (a model 2 B). This small project has been realized for the honeymoon. Let me explain why, before looking at the procedure.

Fish tank and Raspberry Pi

First of all, sorry if lately my posts are published less often than before, but I'm quite busy with several other things and my time for hobbies is quite limited...

Today I will show you a project made for request.

One friend have a small fish tank and he wished to make a really small system, just to check the temperature, pilot lights and few other things .

One Raspberry Pi model A+ was perfect to manage the fish tank with those features, so I decided to start this project and I finished it in few days.

Now this system has been named Aquarius and it's working as it was requested, with some small addition made by myself.

Adding a sensor zone to Sphaera

My Sphaera project is  nice and useful when used alone, but I designed it to be expandable quite easily by adding more Raspberry Pis to the LAN

Also, with the new extremely low cost Raspberry Pi Zero You can add several expansions at an affordable price without sacrifying system performance, as this new board has the same performances of an A+ model.

In this article I will show you just one example of configuration, but adding a new Raspberry Pi would be almost the same for any number of them.

It will be a short and surely not complete description, but could give you a starting point for building something similar. Anyway if you have some question about it, just ask.

Raspberry Pi and astronomy

This time I selected a topic a bit different from usual. After all the blog is about experiments and not only home automation, with RPi...

Since I was a child I've always loved astronomy. I own a small telescope and I took several photos with film cameras, but now I can go a step further thanks to my RPi.

Watchdog for Raspberry Pi

Maybe not all of you know that Raspberry Pi has an integrated watchdog timer. This can be really useful, especially when you need to leave your RPi unattended for some time.

For those who doesn't know what is a watchdog, let's see just a small explanation...

Immagine that you made an incredibily wonderful home surveillance system and you are going to use it to check your house during an long trip abroad. After a bunch of days, something goes wrong and your system hangs, so it become unuseful. The only way to solve this problem would be to reboot the system, but you are away from it...

Watchdogs do this reboot for you.

Make Raspberry Pi SD card last longer

If you have one Raspberry Pi always on or running several hours every day, probably you also had some SD card faults.

Unfortunately SD cards have a limited number of writings allowed. After that number the internal electronics is no more reliable and there could be read/write errors.

Debian usually do several writings on the os partitions, so the maximum writing cycles is rapidly reached.

So, what could we do to make the sd last longer with our RPi?

Using AirPlay with Raspberry Pi

AirPlay is an Apple protocol which allows wireless streaming of audio, video, photo and so on. Even if it's a proprietary protocol, it can also be used with Android devices or personal computers by installing simple apps.

Of course you can also install AirPlay on a Raspberry Pi.

When I built my Sphaera, I also added an external audio card, an audio amplifier and a speaker. Initially I used this audio system just for some notification, but going from that to a wireless speaker it really easy.

Launch Python script at boot

Sometimes we could need to start a Python script when Raspberry Pi boots up in a full autonomous way.

RPi could be really useful if used headless, without a direct user interaction (at least when starting the system), so if we created a script for a RPi that needs to be executed at startup, we also need a way to accomplish this task.

In this post I will describe a way to execute a Python script (but this works also for every other kind of software) when booting the RPi.

Send vocal message using TTS and Yowsup

Last time we saw how to install PicoTTS to make our Raspberry Pi speak. Using PicoTTS (or any other Text To Speech engine you like) and the Yowsup class to send media files that we already used for pictures, we will be able to send vocal messages from the RPi, instead of just text answers.

In the future, if Whatsapp will really enable audio calls (and Yowsup will support them), it would be possible to integrate also a vocal recognition module, so we could ask something to the RPi directly, with just a call and hear the answer.

What a wonderful task from such a small device!

Sending pictures with Yowsup

One feature that could be quite useful in home automation is the ability to send pictures took with a webcam to our smartphone.

This could happen on request, by just asking to take a photo with our parser, or automatically when the script is programmed to do that (at specified intervals or maybe when detecting movements).

3D printer remote control

Let's keep Whatsapp aside for a while... This time I will offer you a short post about a useful Raspberry Pi application if you own a 3D printer.

3D printers are becoming more and more affordable. Still high in price, but today you can buy them for less than €600. They are not really easy to use, but they can be quite useful in many situations. Also for creating cases for your RPi!

Sending SSH commands

SSH is really useful to manage unix devices from a remote place. You can be away from the console, or even do not have any console at all and still be able to enter a unix session.

Of course SSH must be enabled in the host device so that it can accept the connections, but at least in the last Debian distro for RPi this is a default.

Personally I use RPi almost always by SSH. Just at first startup of a Debian installation I can use a console for some network configuration.

As You may have seen in the starting up post, I can also avoid the console for model B or B+, as SSH is already enabled and I can retrieve RPi address looking at my router logs.

Anyway SSH could be really useful also when used to send commands without a interactive session.

Shutdown XBMC (and TV) using command line

Today I will show You how to turn off your TV and XBMC using just command line.

You could ask why someone may wish to use command line for this task that can be easily performed with remotes.

Well, this will be quite useful if You wish to turn XBMC off from another computer using an SSH connection.

I have RaspBMC installed on one Raspberry (model B) and on another one (model A) I'm trying to make some automation. Just by sending a Whatsapp message I'm able to suhtdown RaspBMC and turn off my TV.

This is just a part of the automation involving my home theatre that (maybe one day...) will include much more.

Starting up

Let's start from the very beginning... I know that many people already know how to start with a Raspberry Pi, but for beginners this could be somehow difficult.

In this post I will try to explain the various steps to follow in order to have a Raspberry Pi that is usable without problems.

All my future posts will be based on these steps, unless stated differently. Also I use Windows on my computer to perform some of the steps, so if You need to start from a different system You can go here to find more info about starting from Mac OS or Linux.

Home automation experiments with RPi

I know, there's plenty of blogs and sites about Raspberry Pi, but I wish to share my experiences using this wonderful piece of electronic with all the people that could be interested.

My final goal would be an home automation system, but most of my experiments can be used for many other projects.

I'm not a Linux expert, nor a Python expert, but I've been a programmer for several years, so I can really learn how to effectively use RPi (but it can be programmed also with other languages and even using different O.S.).
Anyway sometimes my approaches could be a bit dumb and some other more experienced user could surely do much better than me.

If You find something wrong in my codes or You think I could do them better, please write this in the comments. It will be useful for me and for every visitor of this blog.

I already published some info and also made available some pre-configured SD image on my personal website, but I think that putting everything in a dedicated space would be much better.

If You wish to visit the RPi pages on my website, go to http://www.mascal.it/raspberry_e.html and follow the links at the bottom for the specific pages.

If You have questions, You can send me an email or comment in this blog...