Apr 092012
 

From a phone call we received last week:

I’m finishing off an art installation to be installed in our local library.  The video projector we’re using needs to run all day, but be turned off each evening when the library closes.  The library staff aren’t available to turn the projector on and off each day, so the process needs to be automated.  Can you help?

It  turns out that this is a bit more tricky than first imagined.  The easy solution, of course, is to plug the projector in to a $4 mechanical timer, then set the on and off interval as appropriate.  However, this won’t work for any modern video projector.  Instead, (once mains AC is applied) they require a ‘soft’ power command, either through a remote control or on-panel pushbutton.  And usually to turn a projector off, the power button is pressed once, and then a second time a second or so later, to confirm operation.

Since the DecaBox already does a nice job recording and replaying IR commands , it made sense to write a firmware module which included a clock and scheduling routine.  Once this is done, any captured IR command can be replayed at any time on any day.

The DecaBox contains an internal socket for an SD memory card.  On that card is a text file called, surprisingly, ‘schedule.txt.’  It looks like this:

As shown above, the projector is programmed to turn on at 09:00 and off at 21:00 weekdays.  At 21:00, the ‘power’ command is sent twice to ensure proper shut-down.  The Saturday and Sunday schedule is different, to match the library’s operating hours.

Here’s a quick video clip showing how easy it is to set up and configure the system:

Need something similar?  Just let us know!

 Posted by at 6:14 pm

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