A fantastic resource for Cocoa, Objective-C and programming in general

The script called PropertyFromInstanceVariable had already been added to by a couple of other people, Yung-Luen Lan & Mike Schrag and Pierre Bernard and I have now shaped it for my own specific needs, and possibly yours too.

The tedium I was trying to eliminate was the process of creating Objective-C properties from instance variables and doing basic memory management on them. This is a repetitive process that seems more appropriate to hand off to the machine.

Matt’s script allows you to take an instance variable defined in your interface file and automatically create a property for it, synthesize the property in the implementation, add a release statement and set the property to NULL in the dealloc method.

For example, running the script on this:

NSString *myString;

would automatically create this in the interface:

@property (nonatomic, retain) NSString *myString;

this at the top of the implementation:

@synthesize myString;

and adds these two lines to the dealloc method:

[myString release];
myString = NULL;

Because this script was written before the viewDidUnload method had been added to the UIViewController class it didn’t make use of the viewDidUnload method. I wanted to update it to set the retaining references to subviews in the view hierarchy to nil. These reference properties may have been set through IBOutlets when loading a nib or programmatically in the loadView method.

I have now modified the script to reflect my own coding habits. It still creates the property, synthesizes it and adds a release to the dealloc method, but if the class is a subclass of UIViewController then this is placed in viewDidUnload like so:

self.myString = nil;

This script can be run on multiple instance variables at once and greatly cuts down on the time it takes to set up a new class. Instructions on installing the script can be found here.

You can get my fork of the script on github.

NOTE: I have updated to script and edited this post to reflect those changes. All links are to the most recent version.

I have already sent off a request for an invitation to the beta version and am watching my inbox with excitement. I can’t wait to use an arduino to start logging some data to share online. I would love to track the sun light in my garden or the energy usage in my house or use Pachube as part of a home automation system. Perhaps I will be able to monitor how much time I spend making music versus downsurfing on the interweb!

There is already a convenient way to follow peoples Pachube feeds on your iPhone but it might also be interesting to explore the API and create a handy Pachube iPhone app of my own.

Setting the Page-Up key-binding in Terminal

Open Terminal then go to Terminal -> Preferences -> Settings -> Keyboard. Scroll down to find the key that you want to change and highlight it. Click the edit button at the bottom of the window. A new window will open like the one pictured above. Set everything as shown and replace the string to send to the shell with the appropriate one from the following list:

Key        Escape Sequence
End        \033[4~
Home       \033[1~
Page-Down  \033[6~
Page-Up    \033[5~

Enjoy.

Open Terminal and type:

defaults write com.apple.itunes show-genre-when-browsing -bool FALSE

Then close and reopen iTunes and voila, genre is gone form the list view.

To put genres back, type:

defaults write com.apple.itunes show-genre-when-browsing -bool TRUE

Your iTunes browser will now look like this:

iTunes with browse by genre removed

Oxygen 49 transport controls

The Oxygen 49 is a natively supported control surface in Ableton Live. To setup the controller go to Preferences->MIDI/Sync and select your device from the Control Surface dropdown list at the top left. Then select your MIDI input and output ports from the next two adjacent dropdown lists. If you are using an Oxygen 49 via USB then the ports will be something like “USB Oxygen 49”. You should now be able to use all of the transport buttons on the controller except for Forward and Reverse which will cause the crazy play-head problem.

A common use of Forward and Reverse transport buttons is to move the play-head through an arrangement window, usually by some user defined length; 1-bar, 8^th notes, 16^th notes etc, and sometimes to navigate through user defined locators. As far as I know the former is not possible in Ableton Live as of version 7, at least not with an Oxygen controller. What we can do though is setup locator navigation by assigning the Forward and Reverse keys to the Previous and Next Locator buttons using MIDI Map Mode. Settings in MIDI Map Mode override control surface defaults.

To enter MIDI Map Mode click the MIDI button at the top right of the Live window. Click on the Previous Locator arrow and press the Reverse button on your controller. Click on the Next Locator arrow and press the Forward button on your controller. Press the MIDI button to exit MIDI Map Mode. Now you can create locators in the arrangement window using the Set Locator button and move through them using the Forward and Reverse transport buttons.

It would be nice to be able to assign these buttons to increment or decrement the play head location by the global quantize amount. Hopefully this will be a MIDI assignable option in future versions of Live. In the meantime this is a much better use for the Forward and Reverse transport buttons than locking up the program.

Trimet

The second bot that I built was a ‘Solar Roller’. It uses the same 1381-based solarengine as the Trimet but this time with a single 0.33 Farad gold capacitor. The body and wheels were salvaged from a VCR and a cassette walkman.

Solar Roller

The 1381-based solarengine works like this: The solar cell charges the capacitor. As the capacitor gains more charge, the voltage across it increases. Eventually the voltage reaches the critical point for the 1381 and it supplies current to the base of the 3904 NPN transistor. This turns the 3904 on so that current is drawn through the motor and from the base of the 3906 PNP transistor. This current turns the motor and the 3906 on, effectively removing the 1381 from the circuit. The motor continues to run as the capacitor finishes discharging.

Solarengine schematic from www.solarbotics.net

To see some great solar bots go here.

Aggregate Device Editor

To accomplish this, open Audio MIDI Setup under Applications->Utilities. In the Audio MIDI Setup menu bar, select Audio->Open Aggregate Device Editor. Click the + button to create a new aggregate device and then in the Structure window select which devices you want to include. As an example, I selected the Duet and the Built-In Output and made sure that the Duet was in charge of timing by clicking the radio button next to it. Now in a program such as Ableton Live you can use both the Duet and the Built-In Output at the same time allowing you to cue loops and tracks before you bring them into the main mix.

You could also create other aggregate devices to allow recording on both your Built-In Input and your external device inputs but be warned that the recording quality may vary between the two devices.