Digital Graffiti – Spray Demo

December 19th, 2008 • 6 comments AIR, ActionScript, Flash, Physical Computing, Projects
Tags: ActionScript, AIR, Arduino, AS3, Physical Computing, RFID

The canvas with the van is not very nice, but just to show you a demo of the spray can. sorry for my bad spraying skills. see a description of the project here.

Digital Spraycan – Demo

December 12th, 2008 • 1 comment Physical Computing, Projects
Tags: Arduino, Physical Computing, RFID

I did this demo video earlier this year while developing the spray can for my thesis project. The RGB LED wasn’t bright enough so I replaced it with a super bright one later on and moved it to the top of the can to lighten up the donut.

BitmapData.draw() is limited to 4096px

December 11th, 2008 • 3 comments AIR, ActionScript, Flash
Tags: ActionScript, AIR, AS3, BitmapData, Flash

Thanks to Jens I figured out another limitation in the BitmapData class. It’s actually buried in the draw() method which doesn’t copy any pixels to the BitmapData object whose target x-/y-position is greater than 4096px (0×1000). You don’t get any error just the pixels won’t be copied. This behavior is the same in FlashPlayer 9 and 10 and of course AIR 1.0 – 1.5.
Actually this is no problem for the regular use of BitmapData in FP9 because the BitmapData size is limited to 2880×2880px but using my BitmapDataUnlimited Class and trying to snapshot a Sprite wider or higher than 4096px won’t end up in your desired result.
As you probably know Adobe changed the BitmapData limit in FP10 to a more flexible one, so you are not limited by a specific size anymore but a maximum pixel count of 16,777,215. This means that you can have a BitmapData up to 8191×2048px without using BitmapDataUnlimited but interestingly you can’t draw a Sprite with the same size to this BitmapData object. I think Adobe forgot about their own secret, undocumented »feature«.

example

Sprite: w=8191, h=2048

FP10 BitmapData: w=8191, h=2048 with snapshot of the Sprite

workaround

A workaround for that problem would be to draw everything directly to the BitmapData or if you have to snapshot a Sprite greater than 4096px you could draw it to 4096px BitmapData chunks and copy them to the huge BitmapData afterwards using copyPixels().

Update December 14th, 2008

I added a draw method to the BitmapDataUnlimited class to bypass the 4096px limit.

Using RFID in an ActionScript Application

December 9th, 2008 • 11 comments AIR, ActionScript, Flash, Physical Computing
Tags: ActionScript, AIR, AS3, Flash, Physical Computing, RFID

In order to receive tags, the RFID reader has to be activated through a click on the image. After that, the different RFID tags (sorry for my tiny tags) are used to create different forms.

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Arduino and the RFID reader ID-12

December 8th, 2008 • 30 comments Physical Computing
Tags: Arduino, Physical Computing, RFID

This tutorial is all about wiring the RFID reader ID-12 and retrieving RFID tags via an Arduino board. There are already a few good tutorials with working code out there, but all of them are quite basic and therefore I want to show you how to use it in more complex applications.

There are basically 2 major differences in comparison to other implementations:

1. software serial
The ID-12 uses a serial connection to send the tags. All the other implementations are using the hardware serial pin (RX) to retrieve the information and send it to the computer. The problem of this setup with the ID-12 blocking the receive pin is that you can’t send any data from the computer to the arduino board anymore. This implementation is using a software serial connection on an other I/O pin in order to maintain bidirectional communication.

2. RFID tag removed
The ID-12 has no native method to determine whether a RFID tag is still in range or has been removed already. With a little workaround you can get this information as well.

but enough talking, get this thing started:
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