18 May 2010
Chinatown Remixed runs from May 8 to June 8, 2010, in Ottawa’s Chinatown district. This is the second year for the annual “art walking tour,” where local businesses, restaurants, and shops open their doors to collaborate with artists, providing art “exhibtions in unusual places.”
Last year, Deb and I made a “Chinatown Remixed” sign from electroluminescent (EL) wire, where the various syllables were individually lit, trigged by pedestrian and auto traffic detected by an ultrasonic sensor (see this previous post for details). This year, the sign is hanging in Umi Cafe (610 Somerset St. W.), although this time driven by random sequences instead of the sensor.
Our new contribution to this year’s event is a window installation at the Oriental Charm gift shop (653 Somerset St. W.):
The installation includes a few light boxes from the Electric Window 4 series:
[After the break: how it all works and pics of opening day ]
By tagging Twitter messages (Tweets) with the hashtag #CTRM, anyone with a Twitter account can add messages to the installation archive. Between the various animations displayed by the boxes, the boxes query Twitter for new messages (tagged with #CTRM), and if a new message is found, the strobe lights flash and the new message is displayed across one of the boxes:
If no new messages are found, an older, archived message from the #CTRM stream is displayed, but without strobes: the strobes are only used to excitedly punctuate new Tweets
Here’s a block diagram of the system:
[ bigger version here ]
Starting at the left, there are 4 LED SCREEN light boxes, each with a corresponding STROBE light (only 1 of each is shown). Each LED SCREEN light box has an XBee radio which allows it to communicate wirelessly with the master CONTROLLER. When one of the LED SCREEN light boxes needs a new text string to display, it sends a request via XBee to the master CONTROLLER.
In addition to an XBee radio, the master CONTROLLER also has a WiFi chip which connects wirelessly to the internet (via a wireless router provided by the venue, not shown). When the CONTROLLER receives an XBee request for a new text string, it sends a command to execute a custom PHP script hosted on my website; after a short delay, the CONTROLLER reads the contents of a txt file also hosted on the website.
The PHP script requests the #CTRM stream from Twitter.com, and formats the results for display on the LED SCREEN, it also archives the messages locally on my website; if there is a new Tweet, this is placed in the txt file that the CONTROLLER reads, otherwise an archived message is placed in this txt file. The PHP script also filters the Twitter messages for a list of unapproripate keywords to avoid vulgarities.
If the master CONTROLLER returns a new message to the LED SCREEN, the STROBE lights are also activated for a few seconds to indicate a new message.
The motivation of having the LED SCREEN boxes connected wirelessly to the CONTROLLER was to be able to install the system on-site without having to run a wired serial bus between all the light boxes and the CONTROLLER. Cost was the main motivation for using multiple XBee points connected to one WiFi/ethernet point rather than adding WiFi to each LED SCREEN box. WiFi was chosen for the CONTROLLER so I didn’t have to worry about its placement relative to the internet connection.
Ideally, the STROBE lights would be wirelessly controlled also, but these were a last minute addition to the system — after discovering them in a local dollar store (!) — and are simply wired directly to, and controlled by, the master CONTROLLER with individual power connections; this saved the time, effort, and cost of developing a network to control them, or modifying the LED SCREEN boxes to support them as peripherals. An improvement for the next iteration, perhaps . . .
Prior to the opening, Deb and I installed the Twitter-enabled boxes within the already-colourful window display at Oriental Charm:
The WiFi controller is located below the display; unfortunately I didn’t take time to snap any pics of it before installing the system so I’ll have to add those later.
Deb designed a great instructional poster for the installation, so we hung that in the window as well:
Here’s the press release we sent out as well, which succinctly describes what to expect from the installation.
On opening day, we did lots of demos, showing people how to add messages to the archive and have them displayed on the boxes:
For those without a Twitter account, or a Twitter-enabled phone (of which there were many), we had a laptop on hand for people to participate through our Twitter account:
Overal, people got a kick out of participating by contributing their own content to the exhibit, and enjoyed the near-immediate gratification of seeing their messages appear with the strobe lights.
We were amused when a friend from Toronto started sending in some “amusing” tweets.
The exbition runs until June 8, 2010. If you’re in the Ottawa area, please check it our for yourself and add some messages! Oriental Charm is located at 653 Somerset St. W., near Bronson, right beside Shanghai Resto. You can of course participate from anywhere, though, by Tweeting w/ #CTRM
Here’s a few more pics; being a lighting installation, it’s best viewed at night!
Happy to have everything installed, we’re already working on bright ideas for next year
We’d also like to thank the City of Ottawa for its gracious support of this project.