7: Prototyping Update 1 (Lucas & Jun)

As of the 4th week of the quarter, we had ordered numerous sensors and actuators in a couple separate orders from Sparkfun and Adafruit: several microphones and LEDs; a small Arduino processor board to fit inside the mat; an Xbee wireless setup, including pairs of shields and two-way receivers, to provide for wireless communication between the lamp and the mat; and a half dozen force-sensitive resistors (FSRs), which research implied would be better to measure movement than piezo mics.

Unfortunately, due to moving houses during the quarter and a lot of mail subsequently falling into a postal nexus (from which a lot of it has not yet recovered), we never received most of that. What we got were FSRs and LEDs, so we decided to work with that.

The first step in prototyping was getting the FSRs to work individually as analog inputs which affect the LEDs. To that end, we used Processing to monitor the serial data and visualize it to help understand what kind of data FSRs could gather, using a modified version of Arduino's Graph example. Here's a video of me applying pressure to the FSR by squeezing it, and the subsequent data visualization in Processing.

We also got an electret microphone/amplifier, which we attempted to use as a second input, but after several frustrating hours of troubleshooting, we couldn't get any kind of reliable data from it. Because of that, we decided to stick with just pressure as an input.

Main problems at this point include:

• How do we handle multiple analog inputs at once and get the data to work together?
• What kind of data can be captured by pressure?
• How can we smooth out the slightly jagged analog input data?
• How do we make this prototype of a wireless product work if we're not able to achieve wireless functionality?