Touch sensors and materials

Touch Sensors

This week we explored different touch sensors, and how we might design and develop different interactions with them. We looked at three ways in which touch can be used as an input: basic, force sensitive and flex. We learned that these touch sensors take in analog values, which in order for us to be able to work with in the Arduino we have to map to digital values. Then we can code the logic on the Arduino platform to create different interactive experiences.

(See Slide 3 for our explorations of the different touch sensors]

For Assignment 2, we explored ways in which touch can be used as an input to create sound. For our output we used a piezo buzzer (though we were thinking that this can be extended to using actually speakers next time).

Experiment One

The first experiment we explored the use of a basic capacitive sensor — just the end of a jumper wire — and how different materials. We tried wood, mango, fingertips, and metal. One thing that we discovered was that there are two parameters that dictate the sound that was generated: 1) the actual values that we got, and 2) the variance in the different values we were getting. For example, the metal of the computer the values jumped around a lot - this is variance. We also noticed that when using fingertips the values jumped much higher than when using other materials.

Experiment Two

The second experiment we explored using a force sensor to do a similar thing - turn touch into sound. With the force sensor we noticed that what can be controlled is on the user side of things. Depending on how long we touch the sensor, we can modify. The idea for this experiment is to create an interface for morse code like communication. So the longer we hold it down the sensor the longer the tone. The shorter we hold down the sensor, the shorter the tone. It is very binary.

Experiment Three

Here we now used the flex sensor. What we discovered here was that the flex sensor created more intermittent values. What was created audibly was a more rhythmic pattern. One of the concerns that we had was because the consistency was less reliable with this sensor, it was harder

Research Existing Applications

We looked at two existing applications of touch interaction. The first is a** touch sensitive painting **where paint is the sensor. The electric paint works as the sensor and when users touch a part of the image they get a sound. The other application is a more commercial application, which is the Native Instruments Maschine. It is a MIDI controller, with various capacitive and also mechanical controls.

New Interaction Ideas and Reflections

As we think about our experiments we left with a few questions: How can we get more variation in the values we get here? How can the Arduino be programmed to map analog values to a wider range of digital values? Can we use a better output device (speaker instead of buzzer) to achieve different tonal effects?