Link: Raspberry Pi: Tweet My IP (and, how to enable a Raspberry Pi to send tweets)

I intend to put my Raspberry Pies to work as intelligent controllers. As long as they stay at home I can easily keep track of the IP addresses they get from my modem. However as soon as my Pies start roaming the world and get connected to strange networks it is not as simple any more.

This little script will help you determine the IP address the Raspberry Pi has received. As soon as the Raspberry Pi receives an IP address from the network’s DHCP server it will send a Tweet, telling what IP address it has received. It can even tell you with what IP address it is now connected to the internet if you want to.

Full article here:
Tweet My IP (SB-Projects On Line)

Related article from same site: Send Twitter messages (from your Raspberry Pi)

Link: Raspberry Pi Multi-Room Audio (Mobile/Tablet/PC Controlled)

I have been lurking on Instructables for a few years but have never posted one myself. Now I have bought a home of my own it’s time to undergo some projects and share them with the community.

In my first project I’m going to show you how I setup multi-room audio that can be controlled by any device with a web browser or an app on your Android and/or iOS device.

Full article here:
Raspberry Pi Multi-Room Audio (Mobile/Tablet/PC Controlled) (Instructables)
Be sure to read the comments under the main article because they provide some additional suggestions and insights.

Link: How to Overclock Your Raspberry Pi

By default, the processor in the Raspberry Pi runs at 700MHz but it can be overclocked. Microprocessors are designed in such a way that they perform one unit of work per clock cycle. One unit of work could be adding two numbers together or fetching something from memory. The faster the clock frequency, the higher the performance. Overclocking means to increase the frequency at which the processor runs. The problem is that each model of microprocessor is designed to run at its default frequency and overclocking takes the processor outside of its nominal design limits. If overclocked too much, the CPU becomes unstable which results in crashes or even SD card corruptions. However modern manufacturing processes mean that most chips, including the Broadcom BCM2835 used in the Pi, can safely run at higher speeds.

Full article here:
How to Overclock Your Raspberry Pi (Make Tech Easier)

Link: Make an Internet Controlled Lamp with a Raspberry Pi and Flask

Here I will be showing you how to turn on and off a lamp from anywhere in the world. However, you can control any device that works by toggling its power source, such as a fountain, TV, Christmas tree lights, projector, etc.

Full article here:
Make an Internet Controlled Lamp with a Raspberry Pi and Flask (jack.minardi.org)

An interesting, but perplexing expansion board for the Raspberry Pi

Expansion board for Raspberry Pi
This afternoon our Twitter stream informed us of the existence of this thing: An Expansion Board Made for Raspberry Pi made by a company called SupTronics, which appears to be headquartered in Shenzhen, China. It can be purchased from this site, and the specifications can be found here. Quoting from that page:

 Introduction

The X100 expansion board designed for use on the Raspberry Pi (RPi) computer platform. The board supplies RPi with a regulated +5V from a wide-range voltage source and also contains a real-time clock, a RS232 master port, a HDMI to VGA converter, 3-port USB hub, memory card reader, and 8-channel darlington Driver.  
Main Features
  • Exactly same size as Raspberry Pi (85 x 56mm)
  • Directly installed into the GPIO header pins with no wiring or soldering
  • 6-23V input to 5V, 3A high-efficiency step-down DC/DC converter to supply your RPI
  • Supports HDMI to VGA (NOT powered by the RPI’s HDMI port)
  • Supports self-powered USB hub (Total 4 ports available)
  • Supports self-powered SD and Micro-SD card reader
  • RTC based on NXP PCF2127AT / PCF2129AT with CR2032 backup battery
  • RS232 Serial Port
  • Having the reset switch convenient to enable RPi reset facility
  • Having two slots to make use of RPi’s FPC connector (S1 & S5)
  • Allowing to stack along with other expansion boards.
  • 8-channel darlington Driver chip allowing to control electronic circuits which require more current to drive them
  • Have DIP switch to remove connection from RPi’s pin header so as to keep using other expansion board with no effect.
 * This expanson board is suitable for Raspberry Pi Rev 2 Model B.

We haven’t actually had our hands on the device, but our initial impression is that it adds a bunch of things that might each be individually interesting to a certain subset of Raspberry Pi owners, but in most cases it will be priced too high to get that one feature you really need, and if you only need one of those features you can probably build it yourself or find a cheaper way to add it. Let’s take each actual feature in turn:

6-23V input to 5V, 3A high-efficiency step-down DC/DC converter to supply your RPI

This in and of itself is great if it works, since the Raspberry Pi is notoriously finicky about power supplies (use one that’s not quite stable enough and you’re likely to have occasional SD card corruption). But a good power supply wouldn’t cost nearly this much. However, if you want to install a Raspberry Pi in a vehicle that only has a 12 volt supply available, or some other situation where the available power is unstable, then this become a more desirable feature.

Supports HDMI to VGA

WHY? Who uses VGA anymore? Oh, right, this came out of China, where the first world dumps all its CRT monitors that nobody wants anymore. We’d have much rather seen this relatively ginormous space used to provide improved audio capability; perhaps a S/PDIF connector supporting full 5.1 or even 7.1 audio. That would have been something we could actually make use of.  And why do they use the word “Supports” to mean “This is included on the board”?

Supports self-powered USB hub (Total 4 ports available)

It appears this means that it includes 4 USB ports. Which is great if you need them, but you can buy powered USB hubs for less than what this costs.

Supports self-powered SD and Micro-SD card reader

Again this is a rather strange way to word this, because the card reader is on the board. Since the Raspberry Pi already has a SD card slot, what’s the advantage of having one on this board? For many users there will be none.

RTC based on NXP PCF2127AT / PCF2129AT with CR2032 backup battery

This is really only useful if you are using your Raspberry Pi in a situation where you can’t update the time from an Internet-based timeserver. And even then, it only matters if keeping something close to the exact time is important to your application. Again, we could see this being most useful in a vehicle-based application.

RS232 Serial Port

This is so early 2000’s. A rare few people might have a use for this (and for those that do, we suspect that add-on serial port circuits are available for less than this) but for most people this is just a useless port that wastes space that could have been occupied by something useful, like maybe a Wi-Fi or Bluetooth module, or any of a number of things that might actually be useful to people in this decade.

Having the reset switch convenient to enable RPi reset facility

A switch that costs less than a dollar to add is hardly a reason to buy this board, but at least it’s more useful than some of the other things they put on here. But, why not a true power switch, that (when used with some software) would do a proper shutdown on the Raspberry Pi? That would have been far more useful. And, viewed one way, giving people easier access to a cold reset is not such a great idea, since every time you use it you risk corrupting your SD card. Yet we understand that it can be a convenient feature if the Raspberry Pi is prone to freezing up occasionally.

8-channel darlington Driver chip allowing to control electronic circuits which require more current to drive them

This appears to be basically a ULN2803A integrated circuit with the outputs brought out to some inconvenient connectors. It’s described this way:

ULN2803 8-channel RC servo port
Bring in some muscle to your output pins with 8 mighty Darlingtons! This driver chip contains 8 drivers that can sink 500mA from a selecable 5V or input voltage supply and has kickback diodes included inside for driving coils. This will let your little microcontroller or microcomputer power solenoids, DC motors (in one direction) and unipolar stepper motors. The GPIO Pins are connected to ULN2803 inputs through a DIP switch, with the its outputs going to two array of Wire-to-Board header. Alternatively, these ports can be used to supply +5V or input voltage to other external circuitry, or embedded devices.Please note that this is an ‘open collector’ driver – it can only be used to connect the load to ground and there will be a 1 Volt (or more) ‘drop’ across the internal transistors.

For some people this might be the most useful thing on this board, although it would be nice if there were better documentation on how it’s used. It appears that this converts the Raspberry Pi GPIO ports to make them behave more like those on an Arduino, though we can’t be entirely sure. But you can do the pretty much the same thing same thing with a cheap breadboard, a ULN2803A (get the kind with long pins, not the surface mount type), some connector wires, and an external power supply. Here you get all that in one package (except you will still need the external power supply), but why on earth did they add those funky little white GPIO connectors on the board? We realize those appear to be similar to the type used to bring power to certain devices (such as some internal drives) but still, the plugs that fit those connectors are not something that the average person is likely to have lying around.

Basically, it’s our opinion, again based solely on the information we can find online, that this will only be a good fit for people that happen to need several of these features, or that simply have money to burn and no inclination to look for other ways to achieve the same results. And (at least in the first world) relatively few people will have use for a VGA port, and probably even fewer for a serial port. We can see some of the other features being a bit more useful, particularly in vehicle based and remote sensing applications, or cases where you plan to power this off a solar or wind-powered source of electricity.

If there is ever a second revision on this board, we would recommend the following:

– Ditch the VGA port and replace it with a S/PDIF audio output.
– Ditch the serial port and consider replacing it with a wi-fi and/or bluetooth connection
– Change the reset button so that it becomes a true power on/off button, so that when the power is turned off it signals the Raspberry Pi to do a graceful shutdown (the equivalent of typing sudo poweroff at the command prompt) and then waits for that shutdown to complete before removing the power. We would expect that you’d need to run a background task to catch the shutdown signal and run the shutdown sequence, but you have to install additional software to make the RTC work, so this would simply be similar to that procedure. And several people have built standalone devices that do this, so it’s definitely possible, and this would be far better than giving a typical user an easy way to do a “cold” reset that might bork their system.
– Add a receiver for an infrared remote (suggested by Jeff Darlington in the comments section)

We neither recommend this board nor advise against it, we’re just saying that depending on the reasons you’d want to use it, there might be better or less expensive options. But if you can utilize several of the functions on this board, then it might be a good value for you, assuming that it works as advertised and that if you plan to use the GPIO connections, you can actually figure out how you’re supposed to connect to them.

OpenSprinkler Pi (OSPi) – An Open-Source Sprinkler / Irrigation Extension Board for RPi

OpenSprinkler Pi (OSPi) is an open-source sprinkler / irrigation extension board for Raspberry Pi (RPi). It is based on the design of OpenSprinkler, but its ‘brain’ is an RPi instead of an AVR microcontroller.

The idea of OSPi first came when I noticed that many users were setting up RPi to work with OpenSprinkler. There are good reasons to do so, for example, to enable logging, to customize the default Javascript files, and to allow more advanced features such as weather-based and learning-based control. OSPi is designed as an extension board that makes use of RPi’s GPIO pins to directly control sprinkler valves, without an additional layer of microcontorller and Ethernet controller. In other words, it is a circuit board that allows an RPi to directly interface with sprinkler valves.

Full article here:
OpenSprinkler Pi (OSPi) (rayshobby.net)

Link: Tutorial – How to give your Raspberry Pi a Static IP Address

To log in to your Raspberry Pi remotely, you’ll need the IP of the Raspberry Pi – this is basically like your house address and tells the host computer where to look for it on the network. By default, the Raspberry Pi will be given an IP automatically by the router (called Dynamic IP and denoted by DHCP) when you connect to a network. However, this can change whenever you remove the Pi from the network e.g. turn it off.

Having a static IP isn’t essential, however it will make repeated access to the Raspberry Pi via SSH much simpler, as you’ll always know that the Raspberry Pi has the same address. Imagine how much trouble your postman would have if your house constantly changed location 🙂

Full article here:
Tutorial – How to give your Raspberry Pi a Static IP Address (ModMyPi)

Links: Raspberry Pi / Linux security series

While this series is intended specifically for Raspberry Pi users, anyone new to Linux that would like to know how to secure their system would likely benefit from reading these articles from “The Unwritten Words”:
Raspberry Pi: Initial Setup (Security – Part I)
Raspberry Pi: iptables (Security – Part II)
Raspberry Pi: fail2ban (Security – Part III)

Link: How to Bake an Onion Pi (Tor proxy on Raspberry Pi)

Feel like someone is snooping on you? Browse the web anonymously anywhere you go with the Onion Pi Tor proxy. This is a cool weekend project that uses a Raspberry Pi mini computer, USB wi-fi adapter, and Ethernet cable to create a small, low-power, and portable privacy Pi.

Full article here:
How to Bake an Onion Pi (Make)