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Increase a wiimote's discoverable mode period for DIY Interactive whiteboard

Discussion in 'General Electronics Discussion' started by andgeo, Oct 25, 2012.

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  1. andgeo


    Oct 25, 2012

    I am new to this forum. I am also new with electronics and all the help I can get is really appreciated!

    I am working on building a wiimote interactive whiteboard

    In brief, a Nintendo wiimote, is connected to a computer via bluetooth. We face the wiimote's IR camera towards a normal whiteboard onto which we project the computer's desktop via a video projector. Once we use an infrared marker to draw on the whiteboard, the wiimote's IR camera "sees" the IR blobs and sends the coordinate data to the PC, which translates the data into mouse movements. Thus, we can use the IR marker to point or draw onto the screen.

    Using the technology a teacher can build a <$100 interactive board. One of the problems faced in making this technology accessible to less tech-savvy teachers, however, is the cumbersome syncing of the wiimote with the PC. If the wiimote is placed on a ceiling, for example, it is very difficult to access the wiimote in order to trigger the bluetooth syncing procedure. Note that the syncing has to be performed every time you turn the PC on.

    I have devised a method which may partly solve the issue.

    You see, in order to trigger the syncing procedure, the user has to press simultaneously buttons 1 + 2 on a wiimote (see button image here). Then, the wiimote goes into discoverability mode for only 20sec.

    However, if the user presses buttons 1+2 again before the 20sec cycle completes, say, every 15ec, then the wiimotes extends its is coverability cycle for another 20sec and so on, until it manages it connect to the computer. When it does connect to the PC, keeping on pressing 1+2 does nothing.

    So, here is my solution on how to extend the discoverability cycle of the wiimote ad infinitum, or at leats, until it manages to connect to a PC:

    A 555 timer circuit is set to trigger an electronic relay every 15sec. The relay turns on one of the two buttons (say button 1), while button 2 is kept pressed using some tape or other mechanical means (or even permanently soldering the switch's contacts) so that it is always ON.

    So, to conclude, button 1 is permanently ON. Button 2, is turned ON every 15 sec using a 555 timer circuit and a relay. Thus the wiimote stays in discoverability mode until it manages to connect to the PC.

    So, in hope that what I have described above is not totally naive, here is my question:

    I am not sure if using a relay is the best solution to turning a switch ON, especially since all solid state relays I have found on the internet are quite big in size, and I am looking to build a circuit that will be small enough to hide inside the batteries compartment of the wiimote (the wiimotes will be powered via external power, so, no problem there).

    Naturally, if you can think of a more elegant overall design that can perform the 555 timer circuit + relay method, please do let me know! I am looking for something affordable and easy to build!

    Thank you so much for taking the time to read!

    Andreas Georgiou
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