We've shared a lot of ways to automate the lights, doors, and furniture of your home, but DIY weblog Mad Science has one of the cheapest, simplest home automation projects yet: turn anything on or off from afar with an old cellphone and an Arduino.

All you need for this project is an old cellphone (with either Wi-Fi connectivity or a pay-as-you-go plan) and an Arduino (along with a few other assorted components for the Arduino). You'll need to know how to get up and running with an Arduino and someone else's code, of course, but the project is very simple: essentially, the Arduino has a light sensor attached that will detect when the cellphone lights up (like when it receives a phone call) and will perform an action in response, like turning on the lights. Throw the whole thing in a box, stick it in a corner, and you have a mini home automation project set up for anything you can think of. There are certainly more sophisticated ways to do something like this, but it's a great way to get started with projects in this realm, and it's very cheap if done right. Hit the link to check out the full how-to.

How to Trigger Anything from Anywhere with Just a Phone Call | Mad Science

Ever wished your house would greet you when you opened the front door, which unlocked automatically when you approached? Or your kitchen kept an inventory of everything inside it? The Jetsons may seem like they've got it all, but with a little patience and the right DIYs, the Jetson'll have nothing on you.

The dream of the house of the future relies on automated systems that ensure you'll never have to get up to do anything or remember to turn anything off. You can pay someone to install a fully integrated system in your home for a few thousand dollars, or you can piece together the elements you want and build your own version of the house of the future. We'll break down some of the more interesting (and ridiculous) ideas room by room that you can implement on your own. Let's get started with the entryway.

Wire Your Entryway to Greet You in Style

You home's entryway is the first thing you see after a long day at work. If you're looking for a little pick me up to enhance your routine, here's a couple clever ways to make your comings (and goings) a more enjoyable experience.

Add Theme Music to Your Arrival

When you come home you want a greeting to remind you that you're truly the king (or queen) of the house. What better way to do that than a custom introduction? DIY blog Dynamic boost "You're the Best Around"). If you don't want your own theme music you can also record a custom greeting.

Parts needed: Arduino ($29.95), MP3 Player Shield ($39.95), ProtoScrewShield ($14.95).

Difficulty: Moderate, requires some knowledge of Arduino.

Make an RFID Door Lock and Ditch Your Keys

One of the trademark scenes in any science fiction film is the door automatically unlocking for the person who has keys. Sure, on most occasions unlocking your own door isn't hard, but with a handful of groceries it's a difficult task. You can piece together your own RFID lock that unlocks with a wireless key and locks itself automatically. It's not the most exciting thing you can do to your door, but it's probably one of the handiest.

Parts needed: It's a long list but totals under $100.

Difficulty: Moderate, but the video shows you everything you need to do.

Augment Your Living Room with Automatically Delivered Entertainment and More

Your living room is likely your central entertainment hub and if you want to rig it up with futuristic-style, it's not hard to do. Not only can you automate your media delivery and accent it with a wide variety of control types, you can even add an instant party button.

Set Up a Fully Automated Media Center

The days of heading off to the video store to physically pick up and bring back a movie are long gone, but unless you can survive entirely on streaming video you need to set up a system to automate your downloads. That means using your computer as a media center.

We've shown you how to set up a fully automated media center before and also shown you how to turn that same idea into a torrent seeding machine. This automates your downloads and places them in the correct folders on your computer so you can share them over Wi-Fi with your television or set up a media computer next to your television. The benefit is that once they're set up all of your media is downloaded and delivered automatically to your computer. If you want to add an additional futuristic element, you can throw in voice commands for a true Star Trek flavor.

Parts needed: Computer, a bunch of free software.

Difficulty: Easy. It takes some time to set it up, but once it's done you don't have to touch it again. Photo by amirmeiri.

Start a Party with the Push of a Button

If cheesy '70s science fiction movies have taught us anything, it's that every room should have a party button. With just a tap of said button, a room is converted into a playground of awesome flashing lights and killer music. One such party button is shown off on the website Plasma2002 and it dims the lights, starts playing music, turns on blacklights, and closes the blinds at the push of a button. Overkill? Probably, but no future-house should be without a party button, even if this one costs a lot to build.

Parts needed: Too many to list totalling $634.

Difficulty: High, but probably worth it.

Hack Your Kitchen to Track Inventory and Hide Shelves

Unfortunately, we haven't reached the point where we can simply ask the kitchen to make dinner (yet), but that doesn't mean you can't trick out your cooking area with a few futuristic ideas.

Create an Inventory and Database for Your Food Items

Since you can't feasibly create a robot to cook for you, the next best thing is a computer that can track your food inventory, work as a kitchen timer, and do everything else a computer can do. If you have an old PC laying around gathering dust you can convert that into a fully functioning kitchen computer complete with a kitchen database. Hacker Ryan of the blog Studio Lights created the iKitchen with a handy iPhone-like interface that can track a kitchen database with a barcode scanner, manage to-do lists, recipes, and plenty more. Of course, if you have an iPad, you can also rig up a cabinet mount like this in your kitchen and get the same effect.

Parts needed: Old PC capable of running Windows XP, Touch Screen LCD ($350, but you can usually find older models for way cheaper), OPOS Barcode Scanner ($90+ but you can find them cheap used as well).

Difficulty: Moderate, the cabinet installation is is the toughest part.

Add an Automated Pop Up Shelf to a Kitchen Island

One of the key features in most homes of the future is the idea that you can stuff storage into tiny places and access the storage with the push of a button. This means creating hidden systems like the fruit rack in Back to the Future so you can make better use of a small space.

This automated pop-up kitchen rack is one pretty simple and easy way to tuck away your appliances or shelves. With a push of a button, the shelf raises and you have access to anything you want. This example has a spice rack, but you could feasibly expand the idea to anything you'd like in your kitchen (or anywhere else in your home), including a coffee maker, wine rack, or even a microwave.

Parts needed: Linear actuator ($129.99), tools to cut into your counter top.

Difficulty: Easy. The installation of the lift (the actuator) is dead simple. The most difficult part is cutting the kitchen counters down.

Set Up Your Bathroom to Monitor Your Water Usage and Guide You to the Toilet in the Dark

You probably don't spend a lot of time in the bathroom on most days, but that doesn't mean you can't install a few simple hacks to make things a bit easier.

Track Your Shower Time and Water Usage

If you're a little groggy in the morning it's easy to accidentally spend a lot of time in the shower waiting to wake up. If your water bill is always high because of this then tracking your usage is the most logical step. DIY blogger Mike Newell decided to create a system to track his shower time and toilet flushes so he can better estimate his water usage. The system works by using an Arduino and a motion sensor to track how long you stand in the shower. It also tracks the number of flushes on the toilet. It's a remarkably simple tool that can not only help you cut down on your water usage, but also help you see how much time you spend in the shower.

Parts needed: Arduino ($29.95), IR Sensor ($2.95), ultrasonic range finder ($25.95).

Difficulty: Moderate. If you're familiar with Arduino it's relatively simple.

A Very Simple Pee-Light to Guide You to the Toilet

Sometimes the key to home automation is not only usefulness, but also simplicity. Case in point, this pee-light that detects motion and triggers a very dim light when you need to run to the bathroom in the middle of the night. The nice thing about this hack is that it doesn't turn on the overhead light and blind you.

Tools needed: PIR Movement Sensor ($9.95), Texas Instruments MSP430 USB Stick ($20), 12v LED Light ($9.99).

Difficulty: Easy if you have a basic understanding of electronics.

Rig Up the Whole House for Automated Lights, Utility Monitoring, and Security

Room by room solutions are great, but if you want to really build yourself the house of the future you're going to need to go for a full-blown home automation setup. The basic elements of a off-the-shelf home automation system are pretty simple: remote light control, power usage monitoring, and home security. Let's take a look how you can build these systems on your own for a fraction of the cost.

Control Your Lights and Outlets with Your Phone

The central purpose of most commercial home automation systems is power control. While those systems require a technician to install and set everything up, Instructables user mrx23dot shows you how to do it with a cheap router. With this setup you can control your lights remotely from your computer or smartphone.

This system uses commercially available power outlets that can run your lights or electronics through a network. The network is created with a cheap OpenWRT like one of these and creates a webapp for controlling any of your electronics from anywhere. It's especially handy if you're renting an apartment or your simply don't want to cut into the electrical system in your walls.

Parts needed: Open WRT router ($20-$40, see list of compatible routers above), Arduino ($29.95), Wireless Remote Controls (3-pack $21).

Difficulty: Hard, but the Instructables guides you through the process pretty slowly.

Monitor Your Utility Usage

As we've seen before, monitoring your power usage is a great way to cut the bills, but it's also incredibly expensive. The cheapest way to monitor your power is to create a system that watches for a blinking light on your power meter, but if you want to actually use that data, you have to send it somewhere. Blogger Antibore's solution integrates that data into a cheap digital photo frame using a custom network setup. The small receiver attached to power meter outside sends data to a server and then displays the current power usage on a small monitor. It's a handy way to track all your power consumption without totally breaking the bank.

Parts needed: Samsung Photo Frame ($65 used), Beagleboard ($89), Xbee to wireless send data ($22.95), ATtiny 2313 ($2.88).

Difficulty: High, but at around 1/5th of the cost of most commercial monitors it's not a bad time investment. You can always skip the digital display and just use the simple monitor tool to track on your computer.

Set Up Your Own Security and Monitoring System

The final essential part in a home automation system is security. The benefit you get from going through commercial service is that the system is installed by someone else, but hacking together your own system is dead simple.

The easiest way to do it is to set up a motion detection camera on your home computer. We've broken down our two favorite options before and both are easy to set up and will notify you on your phone if anything moves in the house. If you're looking for a solution that tracks multiple cameras, Vitamin D allows for several wireless cameras so you can monitor multiple areas of the house at once.

Parts needed: Computer with a webcam, software ($5, $50, or $60 depending on what you need).

Difficulty: Easy. A couple clicks and you're done.

The house of the future isn't going to build itself and with the above hacks you'll be well on your way to a Jetsons style fully automated home minus the robotic maid. You can always pick and choose which elements you'd like, but most of the above projects are accomplished in an afternoon at the most. The above ideas are just a handful of some of our favorites that are out there. Have you made any amazing upgrades to your home to make it more futuristic? Share your ideas in the comments.

With the rapid progression of technology each year, it's easy to accumulate a pile of obsolete gadgets that you just can't bear to get rid of. So don't! Here are our top 10 ways you can take the retired gadgets you've already got and turn them into something that has a solid place in the future.

10. Turn an Old Mobile Device into a Dedicated VOIP Handset

We've seen how easy it is to turn an iPod touch into an iPhone using a few tricks and some sort of VOIP service, and it's just as easy with an old phone—so long as you have a constant Wi-Fi connection. It can be nice to have a home phone or two you can use to answer calls when your cellphone isn't handy, you don't have great reception, and you don't want to leave the VOIP app unattended. So grab a mobile copy of Skype, Fring, Line2, or whatever, and leave it open and ready on your old mobile device. It'll wait for someone to call it, or you can just pick it up and, say, order a pizza without the fear of yet another dropped call.

9. Create a Wireless Internet Radio from an Old Router

Radios and routers aren't exactly technology of the future—more of the past and present, really—but when you combine them with the internet you've suddenly got a pretty awesome device for streaming music. The process isn't even that complicated. All you really need is a particular wireless router (the Asus WL-520GU is recommended in this case) and a USB sound card. Pretty neat.

8. Create a Home Security System with a Webcam

When you buy a new laptop, or even a monitor monitor, these days you're almost guaranteed a built-in webcam. That's great, but what do you do with your old bulky, USB-cabled micro-camera? You use it as a security monitor for your home. You can even make it motion-sensing. Better to have it catching criminals than collecting dust, right?

7. Use an Old PC Fan to Create a Battery-Charging Wind Turbine

Maybe wind power is the future and maybe it's not, but we're headed towards something sustainable so you might as well get started now. If you'd like a means of recharging your batteries without relying on an outlet, create this wind turbine out of an old PC fan. This project involves a little hacking and tinkering, but it's worth it just to have power anywhere the wind blows.

6. Turn an Old Projector into a Book Scanner

Most kids born in the last decade don't know whiteout from Britney Spears, so someday you're going to hear the question "did you really used to read books on paper?" Perhaps it's time to accept the inevitable and realize that the medium we know as print is a bit more ephemeral than we may like. But losing our books isn't an option, so the only thing we can really do is take an old projector and turn it into a book scanner, of course! If you've got the time, patience, or lower-level employee you can torture, this little project will finally help you evolve those dead tree tomes into their next state of being.

5. Make a Touchscreen Tablet Out of an Old Netbook

Netbooks had their moment, but their sales are dwindling thanks to the popularity of the tablet. If you wish your netbook actually was a tablet, you're not really out of luck. Just turn it into one. (That linked post even includes software we made to provide it with a heads up display to make it feel even more touch-friendly.) It's not going to be as magical as an iPad, but it's a fun upgrade for a computer you may not use so much anymore. Alternatively, you can do the same with an old MacBook if you've got one of those lying around instead.

4. Build a Cellphone-Powered Robot

Even your old cellphone, smart or not, has enough power to create a personal robot. The video to the left is proof of how an old mobile can create a "cardboard truckbot." The additional parts you'll need will only cost you $30, and Cellbots provides instructions on how to put it all together. You've likely got an old feature phone you've been planning to recycle for the past five years. Rather than wait for that day to never come, provide that gadget of the past with new life as talking, robotic truck.

3. Turn an Old Computer into an XBMC Home Theater PC

XBMC is our favorite media center software. It's free and it's better than it's paid alternatives thanks to a slick, customizable interface that plays all sorts of media from the majority of networked and local destinations. It can pull content from the web, tell you the weather, double as a retro video game console, and much more. What's really great is that it can run on a super cheap, underpowered nettop. That may also mean your old computer is entirely adequate for the job. Either way, you'll be up and running a home theater system that's ahead of its time before you know it.

2. Automate Your Home with an Old Router

The homes of the future will be automated, but you can have that now with the help of an old router. Said router needs to be OpenWRT compatible and this project will require a few other things, but if you're up to the challenge you'll be controlling your home from your smartphone on the cheap.

1. Turn an Old Computer Into an Internet PVR, Downloader, and NAS

The future of home entertainment ought to be as elegant and wonderful as the systems we can put together ourselves today. Old computers are perfect machines for creating a fully-featured content downloader. You can simply set up automated BitTorrent and Usenet downloads, or go so far as to turn that old machine into a NAS and install Usenet tools like SABnzbd and Sickbeard as well. This will make an old machine, seemingly destined for obsolescence, into an incredibly powerful server that will provide you with virtually any entertainment you want. It's unfortunate there isn't a comparable product and service available for purchase right now, but that's part of what makes doing it yourself seem so amazing when you're through.

Closets are often dark, and the higher up you get the harder it is to see inside. Adding a lightbulb isn't always the simplest, safest, or even cheapest option, but you can solve all of those problems with a few LEDs.

Kelly couldn't put an incandescent light in her dark pantry because the space is too small for it to be safe, and even if it didn't burn down the house her dad is an inspector and would give her grief. So, for safety and sanity's sake she decided to get creative. Kelly found some cheap Christmas LED lights for $2.50 and wired them along the wall and plugged them into a motion-sensing outlet so the pantry would light up when the door opened. The Christmas lights could be attached to the inside of the door frame, so installation was significantly easier than planting a regular light bulb in the ceiling.

If you've got a dark closet and want a good solution, this is it. Be sure to check out Kelly's post for the full run-down.

Four Dollar Pantry Lighting Solution | View Along the Way