Works Like Model

To make our works-like we attached a strain gauge, a button and a red LED to an Arduino. The strain gauge is comprised of black rubber which changes resistance when it is stretched encased in blue rubber which helps make the fin thicker and more sensitive to bending. The strain gauge is in series with a resistor so that the voltage over the strain gauge can be measured by the Arduino and used to tell how much the strain gauge is bending. When the button is pressed, the program looks at the strain gauge readings. If there is a sudden change in the strain gauge resistance while the button is pressed the LED turns on. The LED then turns off when the button is released.

In the actual device, both the strain gauge and the LED would be combined as part of the torch. The strain gauge would also be under a protective mesh so that it could not be poked, and instead had to be bent by being blown on. The single LED in our works like would be replaced by the orange light creating the flame, and the lights in the spiders' eyes. The handmade strain gauge we used in the works like could easily be replaced by a commercially available strain gauge or by a wind sensor for an arduino like this one . We chose to use the strain gauge we used as we accidentally burnt out the arduino sensor linked above and didn't have a spare. In the actual device the button would be a combination of the pressure sensors under each tile in the floor.

Our first concern was the difficulty of blowing out the candle. We tested our works like with over 25 volunteers and 72% of them blew out the candle on the first try, and 84% of them blew it out on the second try. We believe that in a group of 2 to 5 this would mean that a group would likely be able to blow out the candle on one of their first tries, however if the ambient wind in the room allowed the blowing threshold to be set lower, that could increase the ease of participants realizing they are on the right path once they first try blowing out the candle.
Another related interesting piece of feedback came from one user who first tried blowing too softly and she wanted to know if there was a way we could make the candle flicker if the user blew too softly. This flicker lines up well with the effect of the fog (in the looks-like) as the fog moves in an interesting manner when one blows on it.

One of our comments on the concept sketches was that users might find blowing out a candle to be gross. We asked users if they found the experience gross, and out of the over 25 people we asked one of them said it would be gross if the user had to touch the thing a lot of people had blown on, and another user declined to blow on it as he was sick. The other users didn't have any critical comments and replied with things like "I don't find blowing out candles to be gross or disgusting."