[Interactive Devices] LED & Pressure Sensors I

LED & Pressure Sensors
By Hannah Kwah, Joan Li & Putri Dina

The main objective of this project is to create an interactive device by using any of the i-Cubex sensors and an LED strip provided. We are supposed to apply the sensing, computing and effecting methods for our devices to work.

Brainstorm Sketches

Idea #1 – Light Trail
There would be an LED wall installed with pressure sensors placed on the floor. When user steps on the sensors, lights would be activated on the wall to follow the trail of that user.

Idea #2 – Glasses Finder

People who wear glasses always experienced a short ‘blind’ moment every morning when we wake up because we can barely see anything! So finding our glasses (which sometimes magically disappeared even when we placed it right next to us) is such a hassle.

Hence, we proposed to make a pressure sensor device which enables user to detect their missing glasses even in the dark. User simply has to press on the sensor for the LED strip on the glasses to light up.

Idea #3 – Pillow Alarm
What is the most difficult thing to do early in the morning? Waking up without snoozing. We were planning to install pressure sensors on a pillow which will vibrate violently after the sensors were activated for a certain period of time.

Idea #4 – Bicycle/E-bike Signal
More people are using bicycle or the electronic bicycle to commute nowadays. Since they ought to reach their destination as quickly as possible, they started to use the traffic road as well. This is especially dangerous when their bikes have no signals attached to show their intention of going to the left or right.

Hence, we wanted to make use of the LED strips to do just that, a device to help bikers signal the direction they are going.

Final Sketch
After the class voting, our group decided to proceed with the our last idea, the Bicycle Signal. We refined our sketches and planned how to implement this using MAX and Arduino to control the sensors and LED Strip.

We will be using the wireless i-Cubex driver and place a pressure sensor each on the bicycle handles. An LED strip attached on the back of the seat will light up according to the sensor activated. Applying pressure on the left handle lights up half of the LEDs on the left and same goes for the right handle.

In terms of softwares, we are using MAX for the i-Cubex sensors to work and Arduino to manage the LED strip. Hence, a serial communication is needed for both of them to speak to each other.

MAX Process

We started off by trying to get signals from the pressure sensors using the i-Cubex driver.

ctlin is an output that receives values from specific controller number (attaching the pressure sensor to channel 1 will send values to ctlin 1). Then, we wanted to separate the values by using the sel function where a 1 value was received when sensor on the first controller was activated. Otherwise, it would always be 0.

The same idea was applied to controller 2. In the end, we applied bangs to each of them.

Arduino Process
None of us had worked with an LED strip before so we began from the basic; switch and LED light. We searched online for some solution to move on and only managed to get the first few lights on the strip to appear.

After some time, we realized that we attached the wires to the LED strip from the other way round (instead of input to output, we had it from output to input).

We played around with the colours, brightness and delay but still had trouble trying to control the LED lights individually. We also had problems trying to get MAX to communicate with Arduino through Serial Communication.


Moving Forward
– Serial communication (MAX to Arduino)
– LED strip to ‘animate’ better
– Physical prototype

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Believes in creating works that someone can not only see or touch but be part of, to be within them.

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