It’s not everyday that we review software around here, but the folks at Adafruit recently put together an iOS app that I figured might be of interest. Their iPad/iPhone compatible application is called “Circuit Playground”, and it includes all sorts of handy electronics reference tools. For the context of this review, it should be noted that I paid for the application myself, and that I have had no communication with the Adafruit team regarding my assessment of the app.

As you can see from the main screen, the app currently features eight different tools, not counting the “Deals @ Adafruit” entry, since I consider that to be more of a marketing strategy than a real tool. The rest of the items are pretty standard reference fare, in an easy to use and understand package.

The Resistor Value tool is pretty straightforward, allowing you to specify resistance in two ways. You can select the color bands of your resistor and view the resulting value, or enter the resistance to see what color resistor you should be looking for. It supports both 4 and 5 band resistors as you would expect, and features a simple “Instruction Page” (as do all the tools), accessible via the small information icon on the bottom left corner of the screen. One thing I would love to see implemented is the ability to photograph components and display their resistance. I think it would be a very helpful addition for makers whose eyesight isn’t what it used to be.

The Multiple Resistor and Multiple Capacitor tools are similar in function, showing you the resultant resistance/capacitance of various series and parallel component setups. They both support up to 9 items apiece, and let you select the capacitance and resistance values for each component one at a time. This is both good and bad, as it gets pretty tedious entering each value manually after a bit. One other item that I thought could use improvement here was the functionality of switching between series and parallel configurations or adding/removing components. Any time a change is made to the configuration, all of the values are reset – this means that if you add another resistor to your 8-resistor diagram, you must re-enter each and every value.

The LED Resistor Calculator does exactly as its name suggests, much like many online calculators that have come before it. This handy feature lets you pick your LED color from a pre-determined list, populating the forward voltage and current fields automatically, based on some common/standard values. Once you specify a supply voltage and quantity of LEDs, the application returns the exact resistance required to meet your specs, along with the value of the nearest standard resistor. While the tool is certainly helpful when calculating resistors for LEDs in series, it lacks any sort of ability to do the same for parallel configurations. If the folks at Adafruit included that functionality along with the ability to customize the default LED list, I would be thrilled. I do have to point out however, that this tool does retain the LED count and supply voltage when changing LED colors, which is something I was glad to see after playing around with the Multiple Resistor tool.

The Ohm’s Law calculator is a simple tool that is great for allowing me to carry out quick sanity checks of the math I have done in my head. Simply enter two values in the triangle, and Circuit Playground spits out the third. The Power Calculator is a similarly straightforward tool, which takes in two of four values (Power, Voltage, Current, Resistance), calculating the rest for you. Neither tool is overly complicated, but then again they don’t need to be.

The final calculator that the app provides makes number conversions dead simple. Given one number, the converter will give you its representation in binary, decimal, hexadecimal, octal, and ASCII notation. While it might not be something that I’ll use every day, it certainly is a very helpful reference tool. I personally think that this tool would benefit from the ability to convert strings of characters/numbers rather than one at a time, but perhaps that is something they are looking to add in a forthcoming release.

One of Circuit Playground’s features that is not as prominent as the others on the main menu is the built-in datasheet viewer. It uses a lightweight interface to help search through and view PDF files located in the iPhone’s document store. I don’t have anything of the sort stored on my phone so I can’t truly test this portion of the app – let us know in the comments how it works for you.

A few data persistence nitpicks aside, I think that Circuit Playground is a solid app with a lot of potential. At $2.99 it sits at the higher end of the App Store pricing structure, so whether or not these tools are worth it is ultimately up to you. Adafruit does say that anyone who purchases the app gets $3 off their next order in their online store, which essentially makes the app free if you are a regular customer.

While it’s not designed for your seasoned Electrical Engineer, it is definitely a great resource for the part-time tinkerers out there. At the moment, it is an iOS-only offering, but Adafruit says that they will be releasing an Android version at some point in the future. In the meantime, they suggest giving ElectroDroid a try, as it is currently the best app on that platform.

[Tod’s] daughter has a habit of forgetting to take a house key along with her, so he was looking for a way to make accessing the house easier in a pinch. He had tried wireless garage door keypads in the past, but their performance was so-so at best. After scouring the market for commercial solutions and checking out the work of other hackers, he decided that he needed to craft a custom solution of his own.

He started shopping around for wireless-enabled microcontrollers and settled on a Roving Networks RN-XV module, which is designed as a drop-in replacement for an XBee. Paired with a 5v to 3.3v power adapter, the RN-XV is nearly all he needed to interface his iPhone with his garage door opener.

The microcontroller has enough GPIO pins to control the garage door, while also monitoring the door’s status using a simple magnet/reed switch combo. A web server in [Tod’s] house takes input from any phone connected to his wireless LAN and relays the open/close commands to the opener. The opener in turn returns status messages to him via the web interface.

We really like the system’s simple design, and as long as [Tod] has turned WPS off at home, he really shouldn’t have to worry too much about unauthorized entry.

Hack a Day alum [Will O’Brien] recently upgraded his phone, and was trying to find a use for his old one. He always wanted a remote starter for his Subaru Outback, but wasn’t interested in paying for an off the shelf kit. Since he had this old smartphone kicking around, he thought that it would be the perfect starting point for an SMS-triggered remote start system.

He started off by jailbreaking his phone, which allows him to run some Perl scripts that are used to listen for incoming texts. Using a PodBreakout mini from Sparkfun he connected the phone to an Arduino, which is responsible for triggering the car’s ignition. Now, a simple text message containing the start command and a password can start his car from a anywhere in the world.

While [Will] is quite happy with his setup he already has improvements in mind, including a way for the Arduino to send a message back to him via SMS confirming that the car has been successfully started. He’s thinking about putting together a kit for others looking to add the same functionality to their own car, so be sure to check his site periodically for project updates.

If the addition of Siri to your iPhone has given you a somewhat-real life companion (and hope that you might not be forever alone) this hack is right up your alley. [Todd Treece] built a hardware fixiture for the living room which bridges the gap between Apple’s new digital assitant and your television.

The box itself is an Arduino with a WiFly shield and the hardware necessary to make it a universal infrared remote control. He mounted it on the underside of his end table, with the IR LED in line-of-sight for the television. Using SiriProxy he’s added functionality that lets you request a channel change either by the name of the network, or the channel number.

As you can see in the video after the break, Siri has some strong opinions on the quality of programming for certain channels. That and contempt for your inability to just change the channel yourself. But this setup does augment your remote control experience by giving you a synopsis of what’s playing right now for the channel you’ve requested.

[Thanks Dave]

Siri can make appointments, tell you the weather, but now she can start your car as well!

After we showed you how Siri could be hacked to use a custom proxy and execute custom commands, we knew it wouldn’t be long before additional hacks would start rolling in. [Brandon Fiquett] thought it would be great if Siri could remotely control his car, so he built this functionality into Siri using [Pete’s] proxy software.

The hack relies on the Viper remote start system he had installed in his car, along with a few modules loaded into his proxy server. His proxy server tweaks allow Siri to interpret a preset list of commands such as “Vehicle Start” and “Vehicle Arm/Disarm”, relaying the commands to the Viper SmartStart module.

We imagine that the back-end functionality is not unlike the existing SmartStart iOS app, but it looks like [Brandon] beat Viper to the game since Siri has not been made available to 3rd party developers as of yet.

Check out the video below to see Siri in action, then be sure to swing by his web site for additional videos as well as the code that makes this possible.

[Pete] has an iPhone 4s and loves Siri, but he wishes she had some more baked-in capabilities. While the application is technically still in beta and will likely be updated in the near future, [Pete] wanted more functionality now.

Since Apple isn’t known for their open architecture, he had to get creative. Knowing how Siri’s commands are relayed to Apple thanks to the folks at Applidium, he put together a proxy server that allows him to intercept and work with the data.

The hack is pretty slick, and doesn’t even require a jailbreak. A bit of DNS and SSL trickery is used to direct Siri’s WiFi traffic through his server, which then relays the commands to Apple’s servers for processing. On the return trip, his server interprets the data, looking for custom commands he has defined.

In the video below, he gives a brief overview of the system, then spends some time showing how he can use Siri to control his WiFi enabled thermostat. While the process only works while Siri is connected to his home network via WiFi, it’s still pretty awesome.

[DJ FileSpnR] did a number on this IDJ Live hardware to make room for an integrated iPad. Those that have seen the hardware before may not even recognize it. In stock condition the controller has two turn-table actuators with cross-fader control in between them. The iPad perches on top like a book, making it a fairly bulky setup.

In its hacked format, the device is much more mobile. The physical turntables have been removed, and the center console was moved to one side. This leaves just enough room to fit the iPad 2 (the original iPad is probably too thick for this to work). A cresent of the original turn table bezel has been retained to clamp the iPad in place, and to protect the dock connector at the same time. Now the touchscreen serves as turntable control, with physical sliders to the right which mange the cross-fading.

Check out the video after the break where the DJ explains his alterations and demonstrates the finished project.

We haven’t really covered many hacks having to do with Apple’s newest iPhone feature Siri. We’d bet you’ve already heard a bunch about the voice-activated AI assistant and here’s your chance to give it the keys to your house. This project uses Siri to actuate the deadbolt on an entry door in a roundabout sort of way.

This is really just a Siri frontend for an SMS entry system seen in several other hacks. The inside of the door (pictured above) has a servo motor mounted next to, and attached via connecting rod with, the lever-style deadbolt. An Arduino equipped with a WiFly shield controls that servo and is waiting for instructions from the Google app engine. But wait, they’re not done yet. The app engine connects to a Twilio account which gives it the ability to receive SMS messages. Long story short; Siri is sending a text message that opens the door… eventually. You can seen in the demo after the break that the whole process takes over twenty seconds from the time you first access Siri to the point the bolt is unlocked. Still, it’s a fine first prototype.

There’s a fair amount of expensive hardware on that door which we’d like to see converted to extra feaures. [CC Laan] has already added one other entry method, using a piezo element to listen for a secret knock. But we think there’s room for improvement. Since it’s Internet connected we’d love to see a sensor to monitor how often the door is opened, and perhaps a PIR sensor that would act as a motion-sensing burglar alert system.

Don’t need something this complicated? How about implementing just the secret knock portion of the hack?

When [Peter] saw the Sparkfun Magician robot chassis in a recent new product post, he knew instantly that he had to have one for a telepresence project that had been kicking around in his head for a while.

Onto the robot chassis, he added an Arduino to provide the brains of the bot, an Adafruit motor shield for controlling the wheels, and a Pololu Wixel for wireless communications. An iPhone is mounted on the top of the robot, which communicates with his laptop using Apple’s Facetime app. The robot is controlled from his laptop as well using the Wixel, which enables him to direct the Magician chassis as if it was attached via USB.

While he thinks the robot is pretty neat and that it works well, [Peter] already has improvements in mind. The robot chassis is a bit weak on anything but smooth surfaces, so a new set of motors and wheels are likely the first changes he’ll make. He wants to add a servo-based aiming mechanism for the phone’s camera, as well as some sensors to prevent the bot from taking a nosedive off his table.

iPhone aside, this is probably one of the cheaper mobile telepresence setups we’ve seen, so we can’t wait to hear how the improvements work out, and how much they add to the robot’s cost.

It’s no secret that the audio quality of the iPhone’s built-in speakers isn’t exactly what you would consider to be hi-fi. Sound quality aside, there are plenty of times where even the volume doesn’t do the music justice. While you can always go out and buy a fancy dock to amplify your iGadget’s sound, artist [Christopher Locke] has a different take on the subject.

For a while now, he has been constructing what he calls “Analog Tele-Phonographers”, metal sculptures that can be used to amplify a mobile phone’s audio. Built out of steel and old trumpets, his audio sculptures require no electricity, instead utilizing the same amplification technology as the original phonographs.

While the Tele-Phonographers won’t make your iPhone sound like a high quality tube amp, they do undoubtedly increase the phone’s volume and they are nice to look at. We can certainly get behind this sort of recycling/reuse of old items.

Continue reading to see a quick video of his Analog Tele-Phonographer in action.

[Thanks, Chris]

[Evan Flint] and his wife use a lot of online recipes in the kitchen. Rather than printing them out, they bought an iPad as a cooking companion. But in their cramped kitchen he needed to find a place for the high-end hardware that is out-of-the-way yet accessible. Some head scratching and parts bin diving led to this under-cabinet iPod dock.

The dock itself is a cradle made out of sheet aluminum. After cutting to shape, [Evan] bent up the sides and bottom to center the iPad. Since this is not a permanent fixture he needed to make the cradle collapsible. He used a CAD program to design the base tray to let the cradle lay flat, while giving several options to the angle when it is in use. Once the cooking is done just fold it up and the drawer slides make for easy under-cabinet storage.

Because he doesn’t own the house he didn’t want to make permanent alterations to the cabinet. But he does lament the unfinished look of the drawer slides. We’d just grab some pre-finished oak crown molding from the home store and wrap the entire thing. The left-edge of molding could slide out with the cradle when in use.

[KaRMaN] sent us a piece from his blog on what to do with a busted iPhone (google translate). As many iPhone owners have found out, it does not take that much of a fall to render your shiny hand-held command center into a pile of shattered glass. Replacement parts and insurance are available so life goes on, but what else can you do?

One thing you could do if your screen split apart like [KaRMaN]‘s is remove the white LED back light strip from the device and reuse it. Once he removed the LED he had to repair a couple of traces but that is no big deal. Then the strip is probed to see how the individual LED’s are situated, in this case is 6 in series. The strip is hooked up to a 12v power source and now you have a small, but bright light for some midnight hacking.

Provided you haven’t been toiling away in a secret lair somewhere (we’re looking at you [Jack]), odds are you may have seen the news that [Steve Jobs] stepped down as CEO of Apple this past Wednesday.

This earth-shattering news even eclipsed that of the East Coast Megaquakeapocalypse. It sent the blogosphere into a tizzy, sparking a whirlwind of news posts and retrospectives on his career. It’s been impossible to ignore the coverage (we’ve tried), and since we see everyone else writing about it, we feel the need to be at least somewhat up on our current events as well.

At the end of the day though, we don’t care how many patents [Steve] owns, how many failed products he has dreamed up over the years, or that he and [Woz] used to wear matching thongs to the beach in the 80s*.

Nope, we just care about the hacks. So here’s a trip down memory lane highlighting the Apple-related hacks we’ve seen so far in 2011, which will forever be known as the year [Steve Jobs] gave up the reigns at Apple (again).

*Bald-faced lie

XBMC on iOS Devices

Overhauling an old Apple keyboard

Mac Pro serial terminal

Taking secret photos of Apple Store patrons

Apple ][ USB keyboard conversion

Apple ][ Weather Display Parts 1, 2, 3

A pair of security researchers have recently unveiled an interesting new keylogging method (PDF Research Paper) that makes use of a very unlikely smartphone component, your gyroscope.

Most smart phones now come equipped with gyroscopes, which can be accessed by any application at any time. [Hao Chen and Lian Cai] were able to use an Android phone’s orientation data to pin down what buttons were being pressed by the user. The attack is not perfect, as the researchers were only able to discern the correct keypress about 72% of the time, but it certainly is a good start.

This side channel attack works because it turns out that each button on a smart phone has a unique “signature”, in that the phone will consistently be tilted in a certain way with each keypress. The pair does admit that the software becomes far less accurate when working with a full qwerty keyboard due to button proximity, but a 10 digit pad and keypads found on tablets can be sniffed with relatively good results.

We don’t think this is anything you should really be worried about, but it’s an interesting attack nonetheless.

[Thanks, der_picknicker]

[Alex Busman]‘s first foray in iOS programming looks like a pretty useful tool. He came up with Ohm Sense, an iPhone app that will take a picture of a resistor and calculate the value based on the color bands. It’s a great tool that we wish we had when we were starting out. At 99 cents, the app is also much cheaper than the emotional cost of our relationship with Violet.

[Alex]‘s used OpenCV for processing of the image data. The app works by scanning the image from the top-left corner and continuing until it sees a beige rectangle. After a bounding box is drawn around the resistor, the iPhone scans the image for columns of color. After a little interpretation, the value of the resistor is displayed on the screen. While it only works on resistors with beige plastic now, [Alex] says he’ll expand that in the future to include blue bodied metal-oxide resistors. [Alex] says the coding only took a week, so if anyone would like code a similar app for Android, be sure to tell us on our tip line.

This isn’t [Alex]‘s first Hack A Day build. We featured his Handy Board project that uses an NES controller to play some chiptunes earlier this summer. Compared to the projects we’ve let slip over the last few months, it’s good to see someone did something productive with their summer.

[Alex] posted a demo of his resistor app on YouTube. Check it out below.