The Treasure Trove Discovery

DEAR FUTURE ARCHEOLOGISTS!

The location of the last Easter Island statue has been found, however not without great loss. Two brave exemplary archeologists went on a journey to find this treasure, and after navigating treacherous plains and mountains, they landed upon a final battle awaiting them. A secret cave where the statue lied, however, covered by a hidden waterfall. Unfortunately, our two archeologist were unaware of the trap they were about to spring once they touched the statue. Without warning, they were swept away in a large flood of water from the cave-top. Thanks to their sacrifice though, my team of scientists and historians were able to easily navigate the traps around, and the statue was retrieved! After our successful return, we have carefully taken apart the cave to determine exactly how the Polynesia peoples of Easter Island designed such an elaborate trap. Read on to discover how and what we found!

- Howard Carter (famous archeologist)

.

.

Link for YouTube video in case it does not play: https://www.youtube.com/watch?v=VOBDvAkcIN4

Here's what we used on our excavation journey!

1. Rock picks and hammers
2. Maps
3. 5 researchers and their student numbers:
4. Hong Chen (1007650757), Mozelle Ofori-Atta (1007744201), Leila Rashidian (1007899071), Patricia Pham (1007757633) & Nudrat Labiba (1008160446)
5. The name of this research project:
6. ARC385H1: Physical Computing Assignment 02 - the Useless Machine
7. Passion and energy!

The idea of the cave appeared to aim for a waterfall-trap situation, wherein when an individual enters the cave and touches the ‘treasure’ with a button under it, the sensor from the button and the ultrasonic sensor (by the waterfall) will trigger the water from the falls to occur (trapping the individual's hand inside of the cave). For the individual to leave the cave, they must remove their hand from the physical button to stop the waterfalls; removing their hands altogether causes the trap to reset. 

Questions that we assume they had to consider when building:

• How big should the cave be? Height, width, length and depth?
• What material should it be made out of?
• What should the thickness of the plywood be, especially the top, so it doesn't collapse?
• How can the wood be stable while keeping the aesthetic of their plans?
• What should the thickness of the resin be if they were to act as stabilizers for the plywood? 
• Should we create a thick wood wall at the back of the cave and columns to act as stabilizers? Should we use thick resins to hold up MDF? 
• Where will the physical button be located, and how far into the cave is it positioned?
• How can water be prevented from contacting the circuits and the buttons? Where can the button circuits be hidden?
• How can the water be filtered from the most? Where would the filtration system be located? 
• How much power is required to pump the water around in a complete cycle in a loop?
• How much water is required to create a waterfall, but is it not too much or too little? 
• How far does the ultrasonic sensor need to be to sense that the physical button has been activated? 

_______________________________________________________________________________

Cave System 

• MDF (wood) and varnish → Top (Roof/Ceiling) and Bottom (Ground) Portion of the Cave System
• Resin or Plexi Glass (3mm) - The Glass Walls of the Cave 
• Birch plywood (3mm) - The Base of the Physical Model

Water Pump and Filtration System 

•  12V DC Powered Peristaltic Pump
• 12V Power Adapter
• 3/16’’ ID, 5/16’’ OD plastic pipe
• 0.17’’ ID, 1/4’’ OD plastic pipe

Additional Materials

• Button system → the ‘Treasure Trap’
• Ultrasonic 

_______________________________________________________________________________

The trap's design consisted of various parts, such as the cave system, the cave system's base and the cave's mechanical components. 

The ‘Cave’

• The cave system is rectangular-shaped, standing at a height of 15 cm by 20 cm x 20 cm which the walls of the cave are made of clear plexiglass to showcase the inner portion of the cave through aesthetic means (while also allowing the viewer to observe the insides)
• As a cave, it also features stalactites coming down from the roof of the cave further to draw the representation or the mood of a cave; The stalactites are made from wood, laser cut into sheets in a way where they are placid around the tops of the plexiglass to reenact the representation of these stalactite pieces. 
• Inside the cave and sitting in the middle of the cave, there sits a pile of ‘treasure’ and within the pile rests a button which acts as a method of drawing the participant and their attention towards it (and causing them to set off the trap once they activate it by touching it)

The Waterfall

• A prominent feature of the trap, the formation of the waterfall, is curated from a slatted wood plank/piece which rests on the cave roof, allowing the water to fall down and into the moat/ditch.
• The waterfall will continuously activate and run until the participant's hand is completely removed from the button that they pressed inside the cave.

The Moat/Ditch

• A sub-feature of the trap: the water from the waterfall gets collected into this portion of the cave system, in which the water is drained into a hole at the bottom of the moat/ditch so that it can get filtered and pumped to the back of the cave system and into the waterfall space

The Water Pump and Filtration System

• Another prominent component of the trap, the functionality of this feature, is used to create a cycle system for the water from the waterfalls and the water from the ditch/moat to circulate through from between each section/checkpoint (to keep a continuous flow of the water)

Ultrasonic Sensor

• This sensor focuses on sensing the participant's hand, that sends a signal causing the water from the waterfalls to fall onto the participant's hands.

_______________________________________________________________________________

Figure 1 - 3: Sketches of the cave; various iterations of the design of the cave that we imagined they designed, including the measurements of the cave.

NOTE: The previous version of the cave was 30 cm x 30 cm, but has been reduced to 20 cm x 20 cm

_______________________________________________________________________________

The Polynesian peoples of Easter Island, appear to have created a severely advanced electrical mechanism that sensed whether the button had been pressed through the use of what we are calling the Arduino Code and Arduino Circuit. Below is an example of what we determine was their code on managing the ultrasonic sensor, as well as the water pump timing system.

Figure 1 - TinkerCad Arduino Circuit

(Full version of the code: https://www.tinkercad.com/things/hhFRBmQOKco-terrific-juttuli-bombul/editel?sharecode=ly_EG5uIBCZZsc2NMk2l5V7XQS1zOn2H-Obc0CpM9ZY)

The code manages the pump via two systems:

• The button
• The ultrasonic sensor

NOTE: The button determines whether to activate the sensor; the sensor determines whether or not the user is close enough

• If so, pump water and then check again.
• If not, turn off the sensor and stop checking (unless re-triggered by the button)
• FURTHER EXPLANATION OF HOW EACH PART WORKS IS IN THE CODE ITSELF

Arduino Code and The Pump System

1. The pump is managed through an ultrasonic sensor and button, linked through an Arduino / Arduino clone.
2. The Arduino is programmed to determine whether or not to activate the pump through a series of steps:

• If the button is pressed, the code triggers the ultrasonic sensor, prompting it to send a pulse to determine the distance of the person who pressed the button.
• If the sensor determines that a person is “within range,” it will activate the pump and pulse the ultrasonic again.
• If said person is out of range, the sensor and pump will turn off and will not turn on again until the button is pressed. 

_______________________________________________________________________________

Instructions:

These images depict the process of the researchers recreating the cave's typology:

1. Rhino's file of the cave stalactites
2. Taking in the necessary dimensions for the bottom and top part
3. Laser cutting, stacking layers of cardboard onto each other, and glue-ing the parts
4. Applying clay to create an initial layer of aesthetic and water-proof
5. WATER-PROOFEN LAYERS: multiple layers of glue

Materials:

1. Cardboards - 3mm
2. Super Glue

Issues:

1. The larger cardboard pieces were reshaped due to the coats of clay.
2. The exposed non-clayed cardboard parts, when glued with the plexiglass

Better improvements?

1. Leave more time for the clay to dry
2. Determine a way for it to be waterproof in the case water leaked into it

Materials:

1. Birch Plywoods - 3mm
2. Plexiglass - 3mm
3. Super Glue

Instructions:

1. Sketching the initial concept diagrams and determining the dimensions
2. Rhino's modelling the cave in cm
3. Laser cutting the three main parts: wooden base, plexi-transparent middle and the wooden top
4. Trial and Errors

Issues:

1. Water leaked through the unsealed corners
2. The permanently attached three parts removed the ability to add the cave stalactites
3. Aesthetic aspects of the cave
4. The ultrasonic sensor range was incorrect, and the actuator was not activated.

After some more design revisions, we were left with two versions of the cave we figured was most similar to the Polynesia's cave. After spray painting the first box and gluing it together, we realized perhaps it was better not to glue everything until the wires were inserted into the box for the code to run. That led us to the creation of the final box, wherein space was left at the bottom for the wires and the water pump to run through quickly.

Materials:

1. Birch Plywoods - 3mm
2. Plexiglass - 3mm
3. Spray paint + varnish + clay (water-proofing components)
4. Super Glue + well bond + wood glue

Instructions:

1. Sketching the initial concept diagrams and determining the dimensions
2. Rhino's modelling the cave in cm
3. Laser cutting the three main parts: wooden base, plexi-transparent middle and the wooden top
4. Spray paint all of the parts
5. Apply three layers of varnish and wait to dry
6. After claying the stalactites, apply two layers of glue on top to create a water-proof coat
7. Trial and Errors

Issues:

1. The clay absorbed the water and got mussy
2. The water stream was not ideal where it only streamed down in straight line instead of even-spread out

After assembling everything, this is the final rendition of the cave! With the wires embedded under and the water pump well insulated in the box, the core can run smoothly without the box being ruined by water, thanks to the varnished areas of the cave.

What worked well:

• The ultrasonic sensor and its position - enable our plan of trap activation to happen accordingly
• Arduino code - Despite the complex design and idea of our project, we were able to execute the code in the physical world with no drawbacks or problems
• Designing the final rendition of the cave
• Creating the stalactites for the cave

What did not work well (and how we solved the problem):

• From the beginning, we had to keep updating and readjusting the design of the box in a way which would help to prevent water from entering the inside of the cave and impacting the circuits that are a part of the cave
• Adjusting the ramp for the waterfall - the original version of the cave did not have an overhang, which would've caused the water from the waterfall to enter the cave (when a participant puts their hand into the area to push the button)

What can be improved:

• More setting time for the clay and better coats of glue or other chemicals
• Increase the power of the pump to create quick and unexpected booby-trap effects
• Instead of laser cutting the stalactites, we can make the top entirely from clay, which can be good harmful (but dirty) booby traps when water is absorbed.
• Different types of clay?

And so, after many days putting together this journal, you have now seen how the Polynesian inhabitants of Easter Island created their elaborate booby-trapped cave, by reading through our analysis of how they possibly built it. Maybe now you might want to build your own miniature cave with a trap waiting for someone. Good luck out there brave archeologist!