Diving Mask With Add on Lenses

If you are a SCUBA or free diver in need of corrective lenses for your mask, you are likely to find this fix useful. And if you are a maker you can also adopt and adapt this concept for your protective glasses.

While diving underwater, one needs to read dive tables or the dive computer, a watch, the pressure gauge, look at the camera’s viewfinder or display, or observe the small critters on the seabed. The corrective lenses for diving masks that are commonly available are fixed to the glass of the mask. These lenses are either in the form of a prescription lens – the glass pane of the mask is a lens with the required corrective power - or a stick-on lens that is stuck on to the glass pane of the mask. But a fixed lens is very often inconvenient because one cannot adjust it to ones needs.

This project is my way to fix and overcome all these limitations by making my own add-on, movable and adjustable lenses. This versatile system is made with acrylic parts, customized 3D printed plastic components and some simple hardware.

Follow these easy steps to upgrade your outdoor, underwater experience. Let's get making!

The standard and commonly available corrective lenses for SCUBA diving masks have several limitations. They are attached to the glass pane inside of the mask and therefore can’t be moved around. The field of vision and the viewing angle is therefore also limited to the position where the corrective lens is fixed on the glass pane. On the other hand, a movable lens as the one proposed here, allows one to change one’s field of vision according to one’s requirements. By adding the lens externally, one also increase the versatility of the lens.

I placed my mask on a document scanner and just scanned the image of my mask.

Tip: Invert the nose of the mask so that the frame of the mask can rest flat on the glass plate of the scanner.

Now go ahead and take a selfie of yourself wearing your mask. This is useful in order to determine the position of your eyes in relation to the mask.

With any CAD software that can generate vectors, such as AutoDesk Fusion 360, you can import the image of the scan and trace the outline of the mask’s frame as a vector shape. You will also need to trace the border of the lens. This is shown in the sketch above.

Use the 2D sketch of the mask’s frame to design the required customized lenses and add-on frames. Begin by determining the shape and the size of the corrective lenses. These are in turn determined by the shape of the mask. With these profiles, use them to design the frames for the Lens Holder.

IMPORTANT : The shape and size of the lens support frames are constrained by the shape of the lower part of the mask. That is to say that if the lens support frames are too large they will interfere with the nose. Therefore the maximum size of the corrective lenses is determined by the shape of the lower part of the mask.

In order to hold and contain the corrective lens in an airtight container I used the following construction for the lens support frames which is illustrated above:

• The corrective lens is inserted inside of the lens support rim, which is designed to match the shape of the lens.

• The lens support rim has the same thickness or depth of the lens so that the lens fits inside the rim.

• The front and rear covers are glued (I used epoxy) to the rim with the lens inside the rim. This forms an airtight container for the corrective lens.

The design of the lens support frames has to be done at the same time as the design of the outer frame of the mask because the designs of both these frames are inter-related and inter-dependent.

The designs of the lens support frames and the outer mask frame need to be adjusted so that they match with each other. The lens support frames are screwed onto the slots on both sides of the outer mask frame. I used 4 mm dia brass bolts with butterfly nuts. The lens support frames can therefore be made to slide up or down the mask or slightly to the left or right depending on where the lens is required to be positioned during the dive. This is shown in the illustration above

I have made two versions of the add-on lenses, a simple and a more sophisticated one. The latter requires more parts and skills, but offers greater convenience!

Items required:

Simple version

• Corrective lenses.
• Acrylic sheets: 3 mm and 6 mm thick (thickness may vary from lens to lens).
• Epoxy glue
• 2 Brass Screws, 4 mm dia with Brass Butterfly Nuts

Sophisticated version

• Same materials as above +
• 3D printed parts (described below)
• 4 Brass Screws, 4 mm dia with Brass hex Nuts
• 4 Brass Screws, 2 mm dia with Brass hex Nuts

Now that you have all your profiles ready of your customized lens holders and the mask's frame you will need to get the parts laser-cut. Once done you are ready for the assembly!

Go to your optician and buy off-the shelf corrective lenses that are made of poly-carbonate material. Most lenses these days are made with poly-carbonate materials. Poly-carbonate lenses can be ground easily and reshaped to match the shape of the mask.

If your optician can grind the lens to fit the shape and profile of your mask without charging you too much, you can save some time by getting it done (make sure the print out of the profiles are in 1:1 scale). Otherwise a poly-carbonate lens can be quite easily hand ground or filed at home.

NOTE : Add +0.5 power to the power that you would require on land.

E.g. if you need +1.50 corrective lenses on land, get yourself +2.00 corrective lenses. The added +0.5 power is required to adjust the refractory anomalies underwater. I found that if you want to watch objects closer to the eyes, for instance the digital display or a camera, adding more magnification helps. One can therefore get lenses made depending on the type of diving one plans to do. If it’s for taking photos, lenses with greater magnification can be used. If it’s for watching critters on the sea bed, lenses with lower magnification can be used.

Place the lens support rim on the rear lens support cover and glue both together. This bond should be airtight. As can be seen in the image above I have preferred to make the outer lens covers slightly larger than the lens support rim because it gives me the possibility of adding another layer of glue in case some leaks are present between the two pieces.

Tips: I used epoxy to glue the various acrylic components together. Avoid using Cyanoacrylate glues (like Super Glue) because they tend to stain the acrylic with a misty, white film.

Important:

Make sure that the interior surfaces of the frame covers are kept clean and free of glue stains. The lens covers should be thoroughly cleaned before the lens support is sealed. Because once the lens rim is sealed, the inner surfaces of the lens compartment cannot be cleaned!

Go ahead and insert the modified lenses inside the lens support rim, making sure that they fit snugly. Make sure you are inserting the correct lens in the proper orientation. Place and glue the front lens cover to the other side of the rim. Let it dry overnight. You now have an airtight compartment that contains the lens in a pocket of air. Test the water tightness by submerging it into a bucket of water.

Important:

Make sure that the interior surfaces of the frame covers are kept clean and free of glue stains. The lens covers should be thoroughly cleaned before the lens support is sealed. Because once the lens rim is sealed, the inner surfaces of the lens compartment cannot be cleaned!

If the outer mask frame has been sketched and designed properly, it should fit around the mask frame. The outer mask frame can be glued onto the mask frame. I tried a combination of Cyanoacrylate glue and silicon sealant which worked reasonably well. The Cyanoacrylate glue was used in a few spots to fix and hold the frame in place and silicon sealant was used to fill the gaps around the outer mask frame and the mask.

***Although this worked, I soon realized that a removable frame was more convenient and therefore I dismantled it before taking pics (which I will be describing in the next steps). Subsequently I also modified other features of the frame.***

When the screw and the butterfly nut (which hold the lens support frame) are loosened, the lens support frame can be either swiveled around (to turn the lens away when it is not required) or made to slide up and down the slot in order to adjust the position of the lens. However, loosening the butterfly nut causes both the swiveling and sliding of the lens to happen simultaneously, which is not always what’s required. For example if one requires to just swivel the lens and turn it away when it’s not needed, it is a bit difficult to do so without causing it to also slide in the slot. Moreover, this adjustment needs to be done using both hands at the same time; one hand holds the frame and the other handles the butterfly nut. The following feature improves the handling of the lens adding greater versatility and convenience for moving the lens support frame

A mechanism that would allow the lens support frame to be swiveled and rotated, one notch at a time, and with the use of one hand only, could not be found. It therefore had to be created. The following gear mechanism with a locking mechanism was designed and 3D printed. The idea was also to use materials that are resistant to salt water and also readily available to any diver who has access to a 3D printer.

The main body of this gear mechanism which is 3D printed holds a standard, common O-ring that is used for most SCUBA diving tank valves. I found that the 17.5 mm (11/16”) dia (OD) O-ring was of a convenient size. This gear mechanism can be customized according to the type of O-ring that you commonly use so that you can replace it easily. The O-ring acts like a spring and presses the two movable “teeth” against the rotating gear, locking the gear in place. When the gear is rotated, the teeth are pressed against the O-ring which gets compressed, allowing the gear to turn by a notch at a time. In this manner, the gear and the lens support frame which is attached to it can be rotated a notch at a time with one hand only. This has made rotating the lens much more convenient.

The lens holder that will be fitted on to the gear will need to be modified slightly as shown in the images above. As can be seen I altered the existing lens holder. But one could design the laser-cutting accordingly.

As I was trying out some experiments I also decided to develop a detachable outer mask frame. For this I made 3D models and prints of 4 mask frame supports. The base of these mask frame supports should have the same curved profile of the mask frame so that they can fit on the mask and be conveniently glued on to the mask frame. I also incorporated a socket for the nuts at the back so that the screws can be tightened conveniently.

The parts were 3D printed in PLA at a local 3D print shop. Because the print quality wasn't great, so sand papering and filing was needed.

The laser-cut outer mask frame needs countersunk holes to ensure that the screw head is flush with the frame which also gives it a neat look. Repeat the process for all four holes.

To glue the 3D printed mask frame supports onto the mask, screw them onto the outer mask frame. Apply glue to the base of the 4 supports and slide the mask into position. Apply more glue on the frame supports if required.

Important: Make sure that the outer mask frame sticks out a few millimeters in front of the mask frame. This will ensure that when the lens support frames are being swiveled, they are clear of the mask frame and can turn 360° around the screw.

Screw the outer mask frame to the supports that have been glued to the mask.

The images above are self explanatory and in the proper sequence.

Once assembled, just enjoy the power of 3D printing and relish the clicking sounds of the gear as it turns from one notch into the next one.

Despite the poor quality of 3D printing, the gear mechanism was able to perform with these fairly large margins of error... a proof that the design was quite robust. But a more accurate 3D printer would allow the addition of improved features to interlock the various parts together.

Attach the lens holders with the outer mask frame with the screws and butterfly nuts.

When I thought of this concept and before embarking on this project I searched the internet and was rather surprised to find that there wasn't anything similar around. After having gone through all the rigors of designing every details of this concept and product I realized why it wasn't attempted until now. Without the convenience of 3D CAD modeling, laser cutting and 3D printing that has become increasingly available today, this project would have been extremely tedious and laborious to do. With all these handy tools within our grasp, we now have almost infinite possibilities to improve our lives by customizing the products we use to meet our personal requirements.

Happy making, fix your own stuff and go out and have fun.

I will be happy to offer any suggestions to those interested in replicating this product. Questions will be answered in the comments section below.

Don't forget to vote if you liked this project .

Cheers!