Trial and Error: The Story of Two Failed Sensor Projects

Well a lot of learning occurred this week despite not just one but two different projects I built did not work properly. At the beginning of this week, I started thinking about how light plays such a vital role to all of the human senses. Our eyes differentiate space and color based on light frequencies, the source of sounds can be better understood if we can see where the sound waves are coming from, and light can affect the way we smell things. Light has so many variables that I wanted to build something to interact with these variabilities. With my interest in bioaesthetic, I was drawn to the idea of flex sensors controlling the brightness of an LED. I wanted to connect flex sensors to either a glove or directly onto my hand so that when my fingers moved the flex sensors would register to the Microcontroller to change the current level going towards the LED. I got even more excited about this project idea when I found a video on how to build your own flex sensor with simple materials around the house. The video demonstrates that a flex sensor can be made from just paper, cardboard, aluminum, jumper cables, and hot glue.

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First I cut out 10 1mm x 10mm 1 strips of paper. I then shaded these strips with a 9B graphite pencil. Because graphite is metal, it would allow this piece of paper to conduct electricity. I chose a 9B graphite because it is the softest lead type, so it would deposit more graphite onto paper and the denser the graphite, the better the conductor. Then I cut strips of cardboard and aluminum the building the rest of the flex sensor. A thin piece of aluminum goes on each cardboard “finger” . I cut female end of a jumper cable is cut from the cable and stripped away some of the rubber covering to expose the copper wiring. This end is then super glued to the strip of aluminum making sure the wires are in contact with the aluminum. Then the piece of graphite paper is placed on top of the aluminum making sure no aluminum is exposed. If the aluminum from one side of the strip touched the other then the sensor would not work. I needed to make two of these to then glue them together to make one flex sensor. When I stacked these two halves together, I hot glued the sides of together and then on the top of the sensor so that when it bent, the cardboard would be supported. I made three flex sensors that would represent my middle finger, index finger, and thumb. A mini hand was formed and would connect to the Arduino and LEDS. From here it would also connect to an art piece.

Cardboard sensor for scale

Cardboard Flex sensor

Now this where I should have known better. I was so excited about building a sensor and how I could integrate it into my art piece that I forgot to test out that it actually worked. This crucial skipped step would later come back to bite me in the ass. I made an abstract cardboard sculpture that had LEDs placed all around it so that the user could control their experience with the piece based on their hand movements. Unfortunately when I connected the flex sensors the Microcontroller, nothing happened. I took off the additional flex sensors to see if just one work, and all three independently would alter the brightness. I tried making another DIY flex sensor to but it did not work. To say the least I was disappointed. I do believe that I could get these to work and I should have documented how I connected the micro-controller and LEDS because the more I reflected on it, the problem could have been that I did not set up the tech properly.

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I was determined to have an operational project for class, so I found another motion sensor that controlled LEDs on Instructables.com that seemed like it would be a lot of fun. This sensor used an Ultrasonic sensor and a servo to control the brightness of the LEDs. While this sensor was more technologically advanced, I thought that it would be all right because there was clear instructions and coding to build and operate this sensor. I started reading about Ultrasonic sensors to learn more about what they did and how they were operated. I connected the Ultrasonic sensor, the board, three LEDS, and the servo. And again I came up short. I did have to fix the code to get it compile properly, but beyond that I am not sure why it did not work. I checked and double-checked my wiring and to my understanding I plugged in everything properly.

Hopefully next week I will be able to set up an operational sensor!