In this setup, the Arduino sends a message containing the readings from the two analog potentiometers and the pushbutton switch, separated by commas. The computer reads the serial input until the newline, and parses it accordingly.

The result is displayed as a circle on the screen, with its X and Y position corresponding to the analog inputs and with the pushbutton hiding the circle altogether.

The given code is adapted for reading accelerometer input -- the potentiometers have a different input range. So when I naively ran the given code, the circle was out of the bounds of the screen almost all the time:

I added code to log the sensor readings -- you can see it in the console in the screen recording. I then adjusted the map() input range to match.

This new code has the exact same end result, but the Arduino only sends data to the computer when requested. Changed P5 code is highlighted in the editor.

Media controls... potentiometers... my immediate thought was to make a device that uses potentiometers as knobs for controlling media. The idea would be for the device to simulate radio-style controls but for the media player on th computer. Like in a radio, one knob would control the volume, but the "tuning" knob could, for example, cause the player to change playlists.

I had a lot of fun imagining this idea, but something held me back from committing to it. I had some insightful brainstorming with Natalie and Alan from class, and I realized that it was because neither re-creating a retro idea nor manipulating audio are what I came to ITP for. From this and further discussions about the kinds of sensors we could use, I eventually came up with an idea that aligns more with my interests.

The force-sensing resistor is a kind of sensor I hadn't seen before this class. I was drawn to how it, even in its raw form, doesn't explicitly require a human hand to manipulate it, in contrast to the pushbutton and potentiometer. I realized that it could make a good weight sensor.

This reminded me of an idea I've had for a while: a simple accessory for a computer that automatically locks the computer when the user steps away. There are three current solutions for locking computers when the user is not present, each of which has drawbacks:

• Locking after a timeout. (Drawback: Not sufficient)
• Locking when connectivity to a device (e.g., a phone or watch) is lost. (Drawback: Expensive. Also sometimes unreliable)
• Locking when the camera stops detecting a face. (Drawback: Unreliable)

I wanted to design a solution that has a low false positive and false negative rate and a low cost. Could the force-sensing resistor be the answer?

When I'm using my laptop computer, I'm generally always putting pressure down onto it. Either I'm typing, or my palms are resting on the bottom, to either side of the trackpad. The maximum time when I'm applying zero force anywhere on the laptop is probably only a few seconds.

Given this, my project idea is a device with a force-sensing resistor that sits below the laptop, between the feet of the laptop and the table. The device senses if the pressure changes. If a few seconds have passed with no changes, it sense a message to the computer. An app on the computer locks the computer when it receives the message. And it'll pause the music too, hopefully that satisfies the "media" requirement. 🙂

A possible progression of this project is for the device to use two force-sensing resistors, one below either of the lower legs of the laptop. No only will this make the sensing more reliable, but it can make it easier for device to pick up user gestures involving force. (For example, the user can lightly bang both fists on the computer twice to skip the current track?)