A short overview of all the prototype designs we came up with.

Week 1 (14th May- 20th May)

Plan 1: Keep it strictly PH1104 (Mechanics)

• Waistbelt/harness to prevent user from moving
• User walks → button pressed → walk in direction
• Number of clicks → Speed
• Enough friction to push button but reduced friction to allow user to ‘walk normally’

Issues faced:

• Based on research on market models, it is uncomfortable for users and feels unnatural to be in in a harness & waist belts obstructs hand movements
• User rotates  → directions of buttons must change
• Restoring force of spring is difficult to calculate (Must restore fast enough to register no. of clicks when running but not so much that it hinders the user’s experience)
• Difficult to calculate friction needed and to create the perfect amount of friction
• Difficult to damp springs (Oscillating ground will cause increased VR/motion sickness)

 

Week 2 (21st May – 27th May)

Plan 2: The random backup plan that destroyed the first

Basic idea: Lab work → Lab chair → Inspiration

• Adjustable chair/ring height
• Tilt body → move in that direction
• Ring used to help user rotate
• Press ring down → dash
• Tilt ring up → crawl

Issues faced:

• Ring mechanism is difficult to create

HOMEWORK OF THE WEEK SUBMISSION

• For each person to come up with 3 prototypes and show it to others on 29th May 2018

Marcus

Julianna 

Jason

Final Design

Week 3(28th May – 3rd June)

HOMEWORK OF THE WEEK SUBMISSION

• To come up with further ways to improve our final prototype
• To find an appropriate chair to use for our final prototype

IKEA Snille Swivel Chair

Components of the chair (note the amount of space the chair mount provides)

 

Week 4 (4th June – 10th June) – Week 6 (18th June – 24th June)

No new prototype designs for show.

“It’s not that I’m so smart, it’s just that I stay with problems longer.” – Albert Einstein

In our case, we stay with our prototype designs longer 🙂

Week 7 (25th June – 1st July) – The End

Everyone in the group have zero drawing skills/are too lazy/ see no point to draw our third prototype (we did very rough sketches for individual parts and did not draw a clear one during prototyping), plus prototype 3,4 and 5 are very similar to one another (just minor improvements from one another) so I’ll just leave our poster pic here.

An example of the rough sketches we did. For more examples, do check out the whiteboard in the Year 1 Physics Lab 🙂 (Yes, we are part of the reason why most of the markers in the lab are out of ink.)

An illustration of the differences between prototype 3/4 and prototype 5. Basically, for prototype 3/4, we used 2 brass rods attached with a spring to engage the joystick (Large spring is to ensure that the rods engage the joystick and do not exert pressure on the joystick too much). For prototype 5, we switched to a metal rod with a screw on top of it to serve as a cupping mechanism (the screw head cups over the joystick head and engages it). The differences between prototype #3 and #4 are mainly about the rubber and replacing the large spring with magnets instead, so you are not missing out on anything much 🙂

 

The original IKEA Snille Chair (for comparison)

Top part of prototype #5

Bottom part of prototype #5

(Sorry for not having the whole picture of our final product, Jason broke his spectacles in an attempt to get one so we gave up after that.)

• We removed the chair wheels for safety
• Grey pipe that came along with IKEA chair sawed in half, with one half fitted to the base and the other half found in the top part
• Stainless steel pipe and bottom grey pipe secured together with epoxy and screws
• Foot ring to help user to turn and return to equilibrium
• Rubber pieces inserted with foot ring to secure it (the foot ring is too large)
• Arduino fitted on top part of the chair and taped down
•  Inverted joystick attached to top part of chair with hot glue gun
• Copper pipe helps to elongate the joystick and allow it to detect when chair is tilting
• Stainless steel pipe chopped in half, with the gap between both halves covered by top part of grey pipe.
• Spacer & rubber pieces pressure fitted between the two stainless steel pipes
• Top part of stainless steel pipe covered with a lot of O rings and a rubber sheet to help chair restore to equilibrium position

PS: Yes, prototype 5 is our final product.

THE END 😀

(I know that the above two words are not really needed, but I feel weird ending this blog page without a ‘proper ending’)

UPDATE

We have built a new and improved chair #2 after the presentation and the cost of building is about $50. It is very similar to the first chair but major changes include using epoxy putty to secure the base (it is much easier and a lot prettier too!), reducing the length of the stainless steel pipe (it is now shorter than the original children’s IKEA Snille Chair), no footring (even kids can touch the ground while sitting on our chair)  and no sand in the base. I am not including a pic as we did it after the presentation thus I am unsure if I should include it.