We tried to come up with an idea that would stretch through to the project, but did not feel that we came up with any ideas that the whole group could agree on. We had many different ideas, but since we had quite a big group (six persons) we had a though time settling on a specific idea that the entire group would agree on.
There was some ideas of having a sandbag, prepared with force sensors that played sampled sounds when triggered. We felt that this was to big of a thing to fix in the short time we had for the prototype, but we all liked the idea of mapping physical movement to sampled sounds. After a couple of hours the idea had evolved to something where we would play a drum by waving the hands in the air. We also kept the name (BeatBox) from the sandbag idea.
BeatBox
The idea was to put two light sensors at the bottom of two cups and map certain light levels to trigger the playing of a Wave file (via a Java application). The first idea was to let very low values (due to holding the hands close to the sensor) map to one sound, and another interval from holding the hands higher up to another sound. That way we would be able to simulate a drumset by just waving the hands in the air.
Already after the first tests we discovered that the light measurement was to inprecise to allow for this mapping, so we decided to just let the light levels trigger the sound at one level (a binary mapping).To keep the protoype still interesting we decided to place a RFID-tag sensor in the middle of the two cups and make the choice of RFID-tag select which sounds that would play. We hide the tags inside other objects, and make the sound relevant to the object that is placed on the BeatBox. This makes the user feel a correlation between the choice of object and the sounds that are played.
Programming
The Java application is very simple. We designed the instrument selector like a simple state machine that changed state (i.e the sounds that are played) when a RFID-tag was gained by the sensor. If the tag is lost, or an unrecognized tag is gained, the instruments resets to None (and thus does not make any sounds when the light sensors trigger).
The phidgets light sensors give us a integer value of how much light it recieves, and we use a simple "if less than this level, and not already triggered then trigger"-approach to control when the sounds are played.
Images
The design of the box holding the phidget and the sensors. We wanted to make the technology as invisible as possible, adding to an overall plain and simple design.
Since it was not at all appearent what to do with the objects, we decided to show that directly on the product with this sign.
The RFID-tagged objects we used. Currently we have four objects; a lego drum, a toy tiger, a plastic gun and a tennis ball (ball not visible on picture).
