Tag Archives: Projects

Automate Your Home HVAC System from the Internet Using the Raspberry Pi

The HVAC devices in your home, typically the air-conditioner, thermostats, heating and ventilation, use one or more remote handheld devices working on Infrared (IR) technology. As the HVAC devices are from different manufacturers, you will most likely own a multitude of remote devices, making it difficult to handle and set each of them independently.

However, with the Raspberry Pi or RBPi, a small board called the IR Remote Shield and a wireless interface, you can control all the HVAC devices and that too from the Internet. Imagine setting up the environment in your home just as you are leaving office, so that you have a cozy atmosphere to relax at home.

There are two steps in this project. The first step involves teaching the Raspberry Pi and IR Remote Shield combination the codes that the remote handheld devices utilize to control the various functions of each of the HVAC devices. The second step is to connect the RBPi to the Internet through any one of the wireless interfaces such as Wi-Fi, 3G, GPRS, Bluetooth, and ZigBee or 802.15.4. These interfaces are available from Cooking Hacks, and you can choose one.

After you connect your RBPi to the Internet and feed in the IR codes used by your HVAC components, you can use a webserver, a laptop or even your Smartphone to control all your home HVAC appliances from anywhere in the world. But, a few words about Infrared technology first.

Started in 1993, IrDA or Infrared Data Association is the technology popularly used for controlling devices such as air-conditioners, TVs, radios, audio systems and many others. It is based on light rays in the infrared spectrum and invisible to the human eye. Using infrared transmitters and receivers, communication between two devices can be established in direct line of vision. The infra-red transmitters use special types of Light Emitting Diodes and the receiver uses a photocell sensitive only to the infra-red light.

Infra-red communication or control uses serial data transfer by emitting pulses of light, which is coded in binary, a language micro-processors are capable of deciphering. Therefore, for deciphering the binary code protocol that the remote is sending, you must hold the remote in front of the receiver on the IR Remote Shield mounted on your Raspberry Pi.

To decode and copy an IR code, press the “Receive” button on the IR Remote Shield. This will allow RBPi to capture the code the remote button is sending. In the software, you will have to tag each code with its individual function, for example, a certain code may be for raising the temperature and another for lowering it.

Once all codes from all the remotes are in the RBPi, it is a simple matter to map the codes and their functions on a web application. As the RBPi is connected to the Internet, any browser on the Internet can call up the web application, and the specific settings for the HVAC units altered. This allows the software program running on the RBPi to send the altered binary code to the specific HVAC unit via its IR link and change its status.

Energy Harvesting – How & Why

What Is Energy Harvesting – Why Is It Needed?

The process of extracting small quantities of energy from one or more natural, inexhaustible sources, accumulation and storage for subsequent use at an affordable cost is called Energy Harvesting. Specially developed electronic devices that enable this task are termed Energy Harvesting Devices.

The world is facing acute energy crisis and global warming, stemming from rapid depletion of the traditional sources of energy such as oil, coal, fossil fuels, etc., which are on the verge of exhaustion. Not only is the global economy nose-diving, but the damage to the environment is also threatening our very existence. Natural calamities like earthquakes, tsunamis, droughts, floods, storms, etc., have become the order of the day. Economic growth is generating a spiraling demand for energy, goading us to tap alternative sources of energy on a war footing. Our very existence on the planet Earth is at stake, and we must find immediate solutions to meet the energy needs for survival.

Alternative Energy Sources Available

There are many, almost inexhaustible, sources of energy in nature. In addition, these energy forms are available almost free, if available close to the place where required. Sources include: Solar Energy, Wind Energy, Tidal Energy, Energy from the waves of the ocean, Bio Energy, Electromagnetic Energy, Chemical Energy, and so on.

Recent Advances in Technology

The sources listed above provide miniscule quantities of energy. The challenge before us is to gather the miniscule amounts and generate meaningful quantities of energy at affordable cost. Until very recently, this has remained an unfulfilled challenge.

Today, research and innovation has resulted in creation of more efficient devices to capture minute amounts of energy from these sources and convert them into electrical energy. Besides, better technology has led to lower power consumption, and hence higher power efficiency. These have been the major propelling factors for better, more efficient energy harvesting techniques, making it a viable solution. These solutions are considered to be more reliable and relatively maintenance free compared to traditional wall sockets, expensive batteries, etc.

Basic Building Blocks of an Energy Harvesting System

An Energy Harvesting System essentially consists of:

a) One or more sources of renewable energy (solar, wind, ocean or other type of energy)
b) An appropriate transducer to capture the energy and to convert it into electrical energy (such as solar cells for use in conjunction with solar power, a windmill for wind power, a turbine for hydro power, etc.)
c) An energy harvesting module to accumulate, store and control electrical power
d) A means of conveying the power to the user application (such as a transmission line)
e) The user application that consumes the power

With advancement in technology, various interface modules are commercially available at affordable prices. Combined with the enhanced awareness of the efficacy of Energy Harvesting, more and more applications and utilities are progressively using alternative sources of energy, which is a definite sign of progress to effectively deal with the global energy crisis.

Optional addition of power conditioning systems like voltage boosters, etc., can enhance the applications, but one must remember that such devices also consume power, which again brings down the efficiency and adds to cost.

Combining online and offline: the future of cash registers

Hate going shopping in person but don’t want to buy everything online? Consider the future of shopping where cash registers will not just be able to ring up your purchases, but be able to tell you what other items would match the sweater you’re buying that day….including a review of your past purchases.

Love the idea or hate it, that is the future of brick and mortar checkout. Combining the online catalog with a streamlined checkout process, the goal is to help you shop smarter, better and of course, more often.

Intel has a future generation register in development right now that does all of this, plus more. In fact, it is predicted that in the future you won’t even need to bring your credit card – your cell phone will be the method of payment and receipts will be sent right to your phone. Added bonus – no more lost receipts for returns and exchanges.

Take a look at this video that shows what Intel is working on right now:


How to Jailbreak an iPad

Jailbreaking an iPad

If you have an iPad, you may be intrigued by the thought of jailbreaking it.

Jailbreaking a device permits you to install and use third party applications and utility programs. In the case of a jailbroken iPad, you would be able to then run apps like Adobe Flash which is not available through the Apple OS, or access files like you can on a PC. One app that caught my eye was the multitasking app which would allow you to run multiple programs without having to save/close them. Another great app called Wi-Fi Sync gives you the flexibility to sync your iPad with Wi-Fi – no plugged in USB required.

Of course, jailbreaking the iPad is not without risk (the number one concern would be warranty) but PCWorld.com has put together the definitive guide to jailbreaking your iPad. In fact, PCWorld’s guide is so complete, it even gives you instructions on how to revert back should you get cold feet (or have to go back).

Once you’ve hacked your iPad, be sure to avoid the iPad updates from Apple since your device can be reverted to the non-jailbroken state. Should that happen, you can jailbreak your iPad again after the update is installed.

PCWorld – How to Jailbreak an iPad

Make an inexpensive & simple UV LED Torch

UV LEDFrom our friends at instructables comes an easy project for use with UV LEDS.

To make this simple project, here’s what you’ll need:
2 Ultra Violet LEDS
1 1/4W resistors (the value of the resistor needs to be calculated based on the forward voltage of the LED you use)
1 non-working 9V battery (or a 9V battery clip)
1 new 9V battery
Soldering equipment

The full instructions on the Instructables site will show you how to put everything together. Once assembled, the light snaps on to a working 9V battery to function.

Keep in mind, you don’t have to use UV LEDS for this project – you can use any color. Just adjust the resistor required based on the forward voltage and forward current of the LEDS you choose.

Buying LEDS without specs or you don’t remember the specs of the ones you have sitting around? Assume a max of 2.8V – 3V and 20mA. I would think high intensity white LEDS would work really well for this project.

I haven’t put this one together myself yet, but I think a few of these are coming with me on my next camping trip. Nice way to light up the tent and the ‘facilities’ late at night. Fun project – and you probably already have everything you need right on hand.

How to Make Your Own LEDS? Whooooooooa

I found this how-to today on the great Popular Science web site.

Now that I’ve read through the article – I am amazed that I’ve never seen these instructions written up before.

Theodore Gray, who authors their popular “Gray Matter” column, gives the full scoop on the basic materials used to construct LEDS and provides the basic instructions needed to see just how LEDS work.

OK, it is not so easy to find some synthetic silicon carbide (carborundum) laying around, but surely everyone could get their hands on some sandpaper, needles, a 9V battery and a snap. Follow his instructions, and VOILA…you’ve recreated the basic principles behind the creation of LEDS.