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.

Home automation server - Sphaera

When I showed you my RaPiRo some post ago I explained why I would not use it as a case for my home automation server.

Let's summarize just something...

First of all the power. 12 motors are quite "hungry" and this means that using batteries is not an option if you need to keep it active all the day. You need to power with a plug, so it's mobility would be greatly limited.

It's noisy. All that motors can be quite annoying.

It can detect movement, but only when it's not moving itself, so it can check just a small area at a time.

There are other cons, but these are enough to let me think about a different solution for my home automation server.

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.

Webserver on Raspberry Pi

There could be tons of reasons to configure a webserver in your home. From a simple blog (personal, just like a diary, or public if you wish to share your thoughts with the web) to host for an home software repository, a web developing ambient and so on.

For an home automation system, a webserver is probably the easiest way to access your house when you are away.

A Raspberry Pi is a quite useful piece of hardware if you need a small webserver. It shouldn't be used for big systems, where hundreds of people needs to connect at the same time and a lot of data is transferred through the network, but for small tasks is perfect!

Now with Raspberry Pi 2, things are getting even better as this new version is much more powerful than the original one.

Using whatsapp for home automation - Something real

Last time we saw how to start interpreting whatsapp messages using a simple parser written in Python.

What we did was implementing just a small interaction with our RPi and nothing more. Surely it wasn't a real home automation.

Now it's time to try something closer to that definition. I will keep quite simple, but the concepts are valid for more complex situations too.

Anyway I will just take into account only low-level automation. What I mean is that communication protocols like X10, 1-wire, Modbus, ZigBee and so on will not be used, at least for now.

Maybe in a future I could write a post about these, but do not take this as a fact. It just could happen one day...

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.

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...