This project was specifically designed for me to wear at our Cooking with Hardware panel. After a few TeamBlinky conversations around personal data, bio-sensing, and storytelling, I began brainstorming a piece of DIY wearable technology that would reveal what I knew, but no one else can generally tell: my stress level during a round of public speaking. That’s right, I will be showing the audience whether or not I am feeling overly aroused during our talk.
When I place my hand in the pocket of the apron, my fingers will find two electrodes that act as a Galvanic Skin Response (GSR) sensor, which measures skin conductance. When you are physically or psychologically aroused, your sweat glands secret moisture, thereby increasing skin conductance. Here’s how the sensor works:
Two electrodes comprise the sensor: one is connected to power that sends current, while the other is connected to ground via a 200K Ohm resistor that measures difference. The GSR sensor we are constructing here is *very* simple, basically a variable resistor. Ideally, we would have constructed a more complex circuit using a low pass filter and better timing on the code, but I wanted an easy project and entry point for p comp noobs. Hence, it won’t be completely accurate and you might have some noise. For a more advanced version, check out Chris Kairalla’s documentation.
While I don’t have a terrible fear of public speaking, I definitely have overactive nerves. There are five LEDs on the apron. If I am at my tranquil baseline, the LEDs are lit. If I am feeling aroused, the LEDs begin to fade slowly to induce a state of calm. I actually anticipate this will be quite a liberating experience, and that the performative nature of the act will outweigh feelings of vulnerability stemming from such exposure. Bring on the talk.
More documentation on the making process here.