FINAL DESIGN

The “Dark Cool Helmet” project, sponsored by Wearable Sensing LLC, sought to improve upon existing solutions to ensure the EEG+fNIR Hybrid Headset sold by the sponsor functions reliably across multiple users as a mobile platform.

The EEG+fNIR Hybrid Headset is shown below:

The project motivation is to design and fabricate a new prototype that improves on Wearable Sensing iterations that would easily attach to the existing Hybrid Headset and show marketable improvement in headset functionality.

Major requirements request by the sponsor included:

Helmet prevents incident light leakage
Actively cools user
Prevents/reduces sweat accumulation on the scalp so that sensors reading is not disturbed
Helmet does not interfere with function of Sensor Pods of the Hybrid Helmet
Low noise operation and Lightweight for user comfort
Easy removal and consistent attachment for ease of use.
Good aesthetic

Important results of the project:

Helmet succeeds markedly from original iterations
Helmet can be produced affordably by sponsor in the future

Final Design Features

Light-Blocking Vents

Lightweight at 25 g
Lets 69% of airflow through
Blocks out 99% of light
No printing infill needed
Assembled in 4 pieces

Quiet & Powerful Fans

Airflow of 17.2 cfm
Low noise of 62 dB
Flyback protection against circuit damage
Vibration-Damping Padding

Hard-shell Helmet

Lightweight (total 620g)
Shock Resistant
Good light blocking
62 cm max head circumference & no minimum head

Drawstring Curtain (Black Fabric)

Fits many head sizes
Drawstring for snug fit
Fabric made from light-blocking material to block all ambient light
Velcro attachment to helmet

Magnetic Attachment

4.27 lb pull force
Countersunk magnets for secure mounting
Fitted perfectly for Sponsor headset

Our final design combines the above 5 features to accomplish the project objectives fully with outstanding results!
The hard-shell helmet can be SLS printed as 1 piece, providing lighter weight and better aesthetic.
Wiring was done internally for a cleaner outside look.

Performance & Results

1. Temperature Decrease

Testing temperature decrease performance starts by allowing the headset to heat while the helmet is on top of it, but without having the fans turned on. The fans are then turned on once the temperature inside the helmet reached 27°C. We observe:

Exponential temperature decrease
Experiment repeated 4 times across three users with repeated trends
3.2°C decrease over a 10 minute period

2. Sweat Elimination

Testing sweat elimination is done by using a Space Heater near the head with the helmet on, inducing sweat, while fans are to reduce sweating.

The Hybrid Headset readings in this test show:

Near horizontal lines, indicating nominal data
Sweat artifacts reduced with prolonged cooling during testing
Streaming Software shows electric signal across all sensor channels, thus sweat is no longer an issue

3. Light-Blocking

Software reports helmet reliably allows sensor function
Helmet ensures near zero light intrusion in well lit room.
Addition of drawstring curtain ensures light blocking for various head sizes

The Dark Cool Helmet satisfies all desired performance requirements, along with the capability to be modified by the sponsor for better fabrication as a commercial product in the future. The helmet incorporates four low noise fans working in tandem with specifically designed light blocking vent mechanisms in order to produce active cooling to the user. Further, the helmet makes use of high strength, counter-sunk Neodymium magnets for easy attachment and detachment from the existing headset product. The product maintains a low weight solution in order to prevent the user from wearying during usage, as well as providing a low noise environment for prolonged testing procedures that may occur in the future of the product usage by a client.

Comparison to Old Solution

UFO V5 (referring to the same vent shown above) blocks light by 99% under direct strong light source, which is an extreme case to be tested in.
Sponsor's old design had some light blocking, but the current improvement is remarkable and achieves the goal.
The Control on the chart on the left is having no vent.

The fans of choice are extremely quiet but powerful and effective.
Perceived noise at max power from a human's ear perspective is less than half of the noise caused by the sponsor's initially tested fans.
The control in the chart to the left is simply the ambient noise of a room with AC turned on but no fans working on the helmet.

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