GoPro accessory seen from front
Jump To Final Design


The Task

The project was executed towards Top Notch Design AB, a design bureau located in Stockholm. The goal of the work was to develop an action cameras accessory that would improve the quality of captured video by reducing the impact of some common environmental factors.
Top Notch Design Logo

Removing water drops

Top Notch Design suspected that water droplets sticking in front of the lens was a common problem when using action cameras. One of my goals throughout this work would be to solve this problem in a way that allowed for simple integration into an action camera accessory.
Blurry image because of water drops

Integrate proprietary liquid crystal technology

An additional requirement set by Top Notch Design was to integrate their proprietary liquid crystal filter technology into the final product. Today the filter can be found in SKUGGA eyewear, sunglasses that control their shading depending on the brightness of the environment.

The idea was that by integrating the technology it would be possible to add Neutral Density (ND) filter capabilities to the device. ND-filters are used in photography and videography to modulate light intake. This is useful when shooting in bright environments to avoid overexposure or using too high shutter speeds, something that can lead to choppy looking video.
ND-filter demonstration

Work with GoPro

The GoPro Hero 5 Session was selected as the model and make of action camera that the developed accessory should be compatible with. Advantages with using a well established brand like GoPro is the large potential market size and ease of information gathering.
GoPro Hero 5 Session


–The Process–


Identifying User Segments

The number of user segments that could potentially benefit from the proposed accessory was huge. In order to make a meaningful user study possible, a choice had to be made about which segments to focus on. The selection would also help in assuring the existence of a well defined initial customer base that would benefit from the product.

In this work surfers and snowboarders were chosen as the targeted user segments. Both of these segments regularly use action cameras, and are expected to face the problem of drops forming in front of the lens. The large difference in the environments of use was seen as an opportunity to improve the versatility of the final design.
Surfers and Snowboarders

What Do Users Want?

At the outset a number of fundamental questions had to be answered:

  • Is water drops forming in front of the lens really a problem?
  • Is too much light entering the lens really a problem?
  • If that is the case, how are these problems being solved today?

Since these are straight forward questions that do not require a lot of dialog, a survey was used to gather answers. To obtain more in depth knowledge on user preferences around design and functionality, a number of semi-structured interviews were conducted.

Sketch of person being interviewed


The following insight were obtained from the user interviews and survey:

  • No perfect solution exists today
  • The accessory needs to be lighter than the camera itself
  • The accessory should have bright colours for easy identification in snow
  • Users expect accessories to be compatible with the GoPro mounting ecosystem
  • Prioritisation between droplet removal and light intake control varies user-to-user
  • The mounting procedure should be very fast unless the accessory can always stay on without impacting the usability or video quality

Liquid Crystal Technology

As per the clients request their proprietary filter technology would enable the creation of a variable ND-filter that could be digitally controlled.

With the information provided on the working principle of the filter, there was little doubt around the technology’s applicability for controlling light intake. Furthermore the technology has several properties that allow for easy integration into portable consumer devices, such as:

  • Lack of moving parts
  • Low working voltage
  • Low power consumption

Removing Water Droplets

Unlike with the light intake control, there was no ready-made technology available for droplet removal. To develop a technology that would fulfil this function a number of various natural phenomena were tested. Among the investigated phenomenon were mechanical vibrations, hydrophobic coatings and physical displacement through vipers.
Test for water drop removal
Most of the tested methods proved to be lacking in some fundamental way that either diminished their ability to remove droplets, or their integrability into a durable and portable form factor. There was however one method that showed great promise in fulfilling all of the set requirements, the so-called electrowetting on dielectric.

Electrowetting on Dielectric

Basic electrowetting (EW) is the phenomena where a droplets pinning force to a plane is modified by applying a voltage between the droplet and an underlying electrode. In the consumer space the effect is used to create adjustable optical lenses and e-ink displays, but the main use for EW today is in research settings.

When developing new drugs or conducting experiments in microfluidics, so-called lab-on-a-chip devices are sometimes used. These devices allow for precise digital control of a droplet’s coordinates on a plane by using electrowetting on dielectric (EWOD).

In the context of current work EWOD could be used to displace droplets without any regard for which coordinate the droplet is located at. This make the controlling algorithm and electrode patterns significantly simpler than what is required in lab-on-a-chip devices.

Electrowetting on dielectric principle

For EWOD to work a few criteria have to be fulfilled:

  • Working voltage of 60V or more
  • Layer thicknesses in the order of micro-meters
  • Hydrophobic coating applied as the outermost layer

These requirements do put considerable demands on the manufacturing procedures used, but the positive attributes of electrowetting are deemed worth it:

  • All layers can be made transparent
  • No moving parts
  • Extremely low power consumption due to the current flow being close to zero
  • Well understood manufacturing procedures similar to those of capacitative touch screens


To generate a large number of ideas, quick sketches of various possible designs were made.

sketch collage

When promising design directions had been encountered they were further refined through sketching and iterative CAD modelling. At the end of this process a design solution had formed that fulfilled the requirements set by the client and the users, and allowed integration of the necessary technologies.

sketch of final design side
Sketch of final design iso


–The Product–


Select the Functionality You Need

The filter modules comes in two variants: droplet removal and variable ND-filter for light intake control. The modular structure allows the user to only pay for the functionality that they need. It also opens up the possibility of releasing new filter types compatible with the base module in the future.

Droplet repellant filter moduleLight regulating filter module

Mounting Procedure

The first step when mounting the accessory is to install a new lens cover using the eight screws at the front. This is necessary to provide an area against which subsequent modules can create a watertight seal. This step only needs to be done once as the new lens cover can stay on permanently.

Lens cover offLens cover on

The next step is to attach the filter module with the desired functionality into the base module. When this is done the snap-fits on the side lock into place, and an electrical connection is created that allows the filter to operate.

mounting procedure filter attachment

The final step of the mounting process consist of lowering the camera into the accessory and then tightening the knob on the back.

GoPro camera attachment Back of product

User Interface

Part of the clients request was to make the accessory controllable through an app. This hard-set requirement was used as an opportunity to delegate some controls away from the physical product in order to simplify the design.

hands on iphone
The one physical button that is available on the device can operate in two ways, short press and long press. When pressed quickly it turns the device on and off, and when held for a few seconds it puts the accessory in Bluetooth discovery mode for pairing with a phone. The multi-colored LED under the button indicates which state the accessory is currently in.

Button and LED
For the droplet-removing filter the physical button on the device is sufficient as the filter only has two states of operation, on and off. The ND-filter on the other hand needs the ability to toggle between two separate modes: fixed step and automatic. To accommodate switching between these two the phone app will be used.

Dynamic Design

An attempt has been made to convey the movement and action of surfing and snowboarding through the design. For this diagonal lines have been relied upon, something that in photography often is used to create dynamic photographs with a sense of movement.

Diagonal lines in GoPro accessoryDiagonal lines in photography

Photo Credit : Marc Benslahdine


To create good waterproofing around the lens all the clamping forces have been made perpendicular to the sealing ring. This will help in avoiding the problem of water seeping in behind the filter module.

Clamping force acting on the gopro

The USB type C port has been designed as a separate compartment inside the housing. This means that even if one should forget to close the rubber hatch properly, the product will not break.

product with USB hatch closedproduct with USB hatch open


A prototype of the final design was made for testing the mounting procedure and better understanding the overall feeling of using the product. The parts were made through SLS and SLA 3D-printing.

Prototype iso view

front and back of prototype
Filter module and lens module

gopro accessory front

The final product enables higher quality footage in rain and sunshine, through a design that is both portable and durable.

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