Sit & Make: Blueprint

Sit & Make uses data collected from how you sit on a chair to derive a new, more abstract form that can inspire future chair designs. There are two main parts to this project; collecting data from the user and creating forms from that data. Collecting data is largely a technical challenge, involving soldering wires, connecting various sensors and bringing data from them into the computer. Turning that data into a form is where the magic happens and is conceptually more difficult. First, I will focus on how the data comes into the computer. The type of data I have available will ultimately drive how the final from of the chair is created.

Chair

In order to collect data on how the user is sitting, I need to wire a chair with sensors. No any chair will do since the form of the chair itself will determine how someone will sit. In order to encompass a wide variety of sitting positions, I need to use a chair that allows the user to adjust it according to his/her sitting style and offer a broad range of sitting positions

The MILLBERGET chair from Ikea is a good fit. It allows the user to adjust the height, the rotation, and has armrests that he/she can choose to use. The chair is large enough where the user isn’t constrained to sit in one position, but also has enough structure to allow for predictable sensor values. I can measure values at various points along the chair and not have to worry about missing some data or having to put a large amount of sensors to capture everything.

Collecting Data

Now that I have a chair, I need to attach the appropriate sensors and send the data back to a program that I can use to create new chair designs. When it comes to generative form creation, it is hard to look past Rhino and specifically Grasshopper. Grasshopper is a parametric modeler for Rhino that uses inputs and rules to generates geometry. Grasshopper also has its own set of plugins that extend its capabilities to physics simulations and recursive rule application that opens up even more possibilities. One such plugin, Firefly, allows you to read incoming data from an Arduino in real time, allowing for a seamless connection to the physical world. Firefly and Grasshopper provide an easy yet powerful framework for me to transform sensor data into 3D forms. Below is a diagram showing how the data will flow from the user to the final design.

Sensors

Now that the architecture is out of the way, I just have to figure out which sensors to use. I want to capture different types of data from the user and  incorporate as many types of sensors into the chair as possible. However, I also want there to be some symmetry in the arrangement of the sensors as it will be interesting to look at how symmetrically a user sits on a chair and have that reflected in the final design. Here is a list of sensors that I think will be a good starting point.

• 2 x Force Sensitive Resistors: Used to detect pressure. Will be nice to have on the seats and backrest to look at pressure points for each user
• 4 x Flex Sensors: Measure how much the sensor flexes from the flat position. Can also be used to measure pressure points, but in softer parts of the chair that might not offer enough resistance for the FSRs
• 2 x Soft-Potentiometer: Measure where the user is touching. Will be useful to put on the armrests to see if and where the user places his/her arms.
• 1 x Temperature Sensor: Used to measure temperature and the user’s body heat. This can be placed near the lower back area. The temperature will also go up the longer a user sits on the chair
• 1 x Ultrasonic Sensor: Used to measure distance. I can place it on the bottom of the chair and measure any height adjustment the user makes to the chair
• 1 x Accelerometer: Measures acceleration. I can see how fast the user is swiveling around in the chair or how hard or soft he/she sits down.
• 1 x Methane Sensor: For Farts

My next steps are to implement the physical portion of Sit & Make. I will be creating test circuit and then attaching all the sensors to the chair and bringing the data into Grasshopper via Firefly. As always please let me know if you have any thoughts or ideas.