here comes the spider

Project Description 

“Here comes the spider” is a part of a Haunted Spaceship interactive installation created for the Creation & Computation class. The assignment was to create a responsive environment  using Arduino hardware and software.

In this project I used Arduino Uno board, Infrared Proximity sensor, LED white light, mini servo motor and 330 resistor. I also built a housing box from white foam core and mixed a large amount of green transparent sludge using water, Guar Gum, Borax and Glycerine. I used the recipe  from Stratford Festival prop department, which was given to me by Monica. I also used a plastic spider as a servo motor arm.

The final product was a spider covered in bright green goo on top of a box housing the board and all the components, which moved with a different speed depending to a proximity of the viewer.

Circuit Diagramms 

 

here goes the spider

goo_sweep_with_spiders _schem

 

 

Code

https://gist.github.com/tatianajennings/1e3b5b96031dae2d305f

Process Journal 

My goal was to use some of the sensors and motors we learned about in combination with Arduino board and the basics of arduino   programming language in order to make an object to respond to human presence and behavior.  In a very simple way.  To tell the truth I was not thinking about artistic value of this work or the complexities of narration. In response to the “space station” idea  in combination with the haunted house theme I came up with the most obvious visual cliche – goo. It must be the result of all those alien movies with insect like repulsive creatures dripping something from their mouth.

The first idea I had was to have a transparent container/small fish tank full of green jello with a servo motor and Arduino hidden in the lamp housing and agitating the jello when someone comes close. I was hoping that the jello would be moving and shaking as if something alive was going to come out of it and attack you . I researched the jello like synthetic substances since I didn’t want to use the food stuff and have to refrigerate it. Googling slimy toys and alien brains produced a variety of exiting looking stuff  I imagined would be available at the local toy store.  Unfortunately aliens are out of fashion at the moment and all I managed to find was one sad looking ninja turtle capsule with watery substance of strange colour.  A trip to the halloween party store was unsuccessful as well and in a fit of desperation I purchased half of a rubber heart and 2 plastic spiders.

I had to rethink my idea incorporating whatever I had at hand. This was the first time when I actually thought about what kind of sensor I would like to use. Since the only sensor I used in class so far was the light sensor I had to research what else was available and what it means to have a sensor measuring a change in certain condition.  The sensor measuring distance seems  to be appropriate and I found a few types available at Creatron. My first choice was an ultrasonic sensor but they were too expensive and I bought the proximity sensor instead. I also purchased a bigger and brighter  LED.

When I laid out the actual physical objects I had I realized that in order to hide the board, motor and the sensor I will have to build a box and whatever I wanted to move will have to live on top of it. I still was attached to the idea of something slimy but the issues of finding it and figuring out how to contain and move it was making it unnecessary difficult. However on Thursday after we were describing our ideas in class Monica told me that there is a recipe  for a sludge like  substance Stratford Festival uses in Alice in Wonderland show. They make buckets of it every show for their Humpty-Dumpty death scene. She emailed me the link and I was able to find all the ingredients. Unfortunately I left the sludge making till the very last moment.

I didn’t have much problem connecting  the sensor and the light to Arduino board using the examples on Arduino site and researching this particular model of proximity sensor GP2Y0A41SK0F IR on line. I found a Lucky Larry’s blog with this exact sensor used for distance calculation and I used his code in my program.

Writing of the program was a very difficult enterprise. I am an absolute novice and although I am starting to understand the logic of code writing I am still far away from writing something on my own. The best I can do is to combine some stuff from examples and exercises and try to adjust it. I had a plan that I can use the two pieces of code we tried out in class and I understood – Sweep and Calibration. I was going to add to that Lucky Larry’s code for the sensor and hope it will work. However Larry’s code was more complex than my understanding.  Since Kate mentioned that it’s ok to ask for help  if it will help you to learn things out in the process – I asked my partner to help me and together we tried to figure it out.

The main problem was to calibrate the movement of the servo arm in a way that it produced a realistic movement and had just the right timing of the delay to move all the way. If the delay was too short the arm didn’t have enough time to make the full sweep and return to the position 0. The other problem was to calculate the distance and to relate it to the intensity of the movement. My idea was that shorter the distance measured by the sensor is – faster is the movement of the servo. We used the serial monitor to find minimum and maximum proximity values and to try out different combinations of proximity and delay time. If the delay was too short the movement didn’t have enough range to be distinctly faster. The servo was moving in steps of 1 degree. I also wanted to have the LED to be connected to the proximity and to come on slowly depending how close the person was. However I was unable to make it work and the LED had only two states – on and off.

After I built the box and attached the Arduino and the motor inside it – I started with the goo. Unfortunately the recipe didn’t seem to be accurate and I spent hours trying to make it the right consistency.  I also wasn’t sure about the type of a container, which would work with the box I built and  look good. It couldn’t be glass because I had to cut a hole in the bottom of it for the servo. The spider was the last second idea. I attached it to the servo instead of an arm and it fit perfectly. I couldn’t completely abandon the goo idea since by that time I made buckets of it – so I poured some of it on top of the spider hoping that it would make it more alien looking. I was not sure that the whole contraption will survive the trip downtown – but it did and worked perfectly all evening long!

 

Looking back I find that the whole experience was very involving and exiting. However after I saw everybody else present their work and had time to reflect – I find that I would approach the next project (if we will have to do similar projects in the future) differently. I would try to think about the environment and how I want to affect it in more complex ways  and I would think about technology in that context. And see what’s possible. At least as a starting point. Making something work is challenging and interesting too, but having a more complex idea around it might help to focus the mind and to see some unexpected solutions.

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