Introduction: Carrying (and Charging?) Case for Bluetooth Earphones - Open Source

This project started from the moment I had to recharge my new bluetooth earphones battery on my laptop which only has USB C ports. The issue is this: I have to use a dongle to be able to connect any USB type A to my laptop, then I need a 'USB to mini USB cable' to connect the proprietary connector (included with the earphones) to the remote control on the (sort of) wireless earphones. In other words, it is a huge cumbersome mess.

For quite some time I have been hesitating about going fully wireless (my earphones and power suppliers are the only wires I need on a daily basis), mostly because I really enjoy listening to Hi-Res music and Bluetooth earphones don't offer the same quality as wired ones. The lack of a headphone jack on my mobile phone (and after breaking a couple of expensive dongles) forced me to give wireless headphones a try.

I knew that the added convenience will come at the expense of some compromises but after going through the process of recharging the earphones few times I realised that they were too many so I had to do something to improve the whole experience. I didn't want to remember myself to carry and put together the cable, connector and adapters every time I needed to recharge the battery. I want to enjoy the benefits of wireless earphones without most of the inconveniences.

Nowadays, some wireless earphones (particularly those truly wireless) come with carrying cases and some other even include an extra battery embedded into its case that serves as a power reserve while on-the-go. Unfortunately, most of these premium earphones are quite expensive and more often than not the extra cost is not justified by the relatively limited benefits and the restrictions that come with them (i.e., proprietary connectors, bulky cases, small reserve battery, etc)

The main objective of this project is to design and develop a solution that help mitigate or even solve most issues associated with wireless earphones such as:

- lack of carrying case

- Cumbersome charging process

- Short battery life / lack of power reserve

Since there is a wide variety of earphone brands and models I had to narrow the scope of the project, giving priority to

- popular in-ear earphones

- semi wireless

- models with short battery life

- models without a carrying case

Step 1: Design Requirements

The first pair of earphones I will be working with is the Jaybirds X3. I expect that due to this earphones popularity there is a good chance that there will be more people interested in the project and actively contribute to make it a reality.

After some time thinking about potential solutions and features I came out with these requirements:

The solution should be:

- Compact and lightweight

- Ergonomic

- Intuitive and easy to use

- Practical and convenient

- Relatively easy and inexpensive to manufacture

Ideally it should offer:

Charging mode

- Connector, cable and adaptor(s) included.

- Tidy wires.

- Stand on itself

- Rechargeable battery (possibly on a second model)

Carrying mode

- Easy to open and store earphones

- Slots/compartments for ear tips, cleaning cloth, etc.

- Dust proof

- Water splash proof

General dimensions of earphones, cables, connector and ear tips can be found in the attached PDF file.

Step 2: Design Ideation, Sketching and Modeling

Giving a physical shape to a concept is quite a challenge on itself so it's important to use as many tools, materials and techniques as possible to achieve the desired results. In my case, since hand sketching is not exactly my forte I also relied on feedback from making simple foam/cardboard/wood models and 3D CAD drawings. Also spent lots of time staring at the ceiling imagining different design ideas. Whatever works!

During this stage I made use of simple 3d models to help me decide on some important aspects of the overall design such as the volume, ease of use, ergonomics and some specific dimensions.

I took notes and made to-do lists to keep the project on track and follow up on some pending details, measurements and final decisions.

Step 3: CAD and 3D Printed Prototypes

Depending on each person's level of experience with CAD software this step could most likely be the most challenging and time consuming one.

The final model I have shared in this document is already a working prototype and can be 3D printed without the need to modify the Fusion 360 file. Likewise, the STL files are 3D printing ready and can be taken to any Maker Space to get them printed and then just clean them up and finish them as you want.

Having said that, I would like to emphasise on the Open Source aspect of this project and the needed feedback, technical input and collaboration from other members of this community. I understand that some people don't have the tools or resources to help with some of the most technical aspects of the product development, nonetheless any feedback is welcome in the comment section.

Feel free to download all the included documents and 'hack the heck' out of them. lol

Step 4: Fusion 360

I recently started using Fusion 360 so I had to face many difficulties but in the end I have learnt a lot from them. Most of my experience with 3D software comes from Solidworks and Inventor, so I was able to figure out some things by myself but I always ended up watching Youtube tutorials to get some extra tips and tricks.

This guy is really good at Fusion 360 and his explanations are easy to follow

The design features ergonomic features on the top and bottom parts to fit nicely in a pocket on either horizontal or vertical position. The curves on the headphone case also fit perfectly on the hand making it easy to hold and handle.

The hinge is designed in a way that allows to 3D print all the parts separately and use any piece of metal (2mm diameter) as the pivot. I'd suggest to use an aluminium rivet (17 mm length x 2 mm diameter) and cut it to fit into the hinge.

The middle part would hold the ear pieces in place during charging and the wire will be inserted into 2 slots that lead the rest of its length to the back of the case, leaving only the earphones and control visible when the case is open.

There is a special space for the charging connector which, once in place it will be tightly held in position. At the back of this feature there will be the USB cable, plugged in and secured. A small hook hold it in place and can be easily slide out when the earphones need to be recharged.

The case locks itself when closed and can be easily open by pressing the right side and pulling up the lid.

The Fusion 360 model features a Drive joints with limited degrees of freedom to allow realistic motion analysis. New versions of this model can use the same joints or new ones can be added. Details of this feature can be seen in the linked video.

Step 5: 3D Printing and Testing Finishes

The 3D model requires the use of supports, specially the 'Middle part' so the hook on the back and the cubic space for the connector can be printed without having material hanging (which could change the size of these features).

I recommend printing the model with as much resolution as possible (.1 mm would be ideal) since there are some very small features that would be render useless if the 3D printer can not stick to the original measurements (i.e., hinge holes and locking mechanism).

PLA could be used for the model itself as it is strong enough to be used in a daily basis. I believe ABS or Nylon can also work very well. The use of dissolvable support material would be ideal but I believe it's not indispensable.

On post processing, I've been able to achieve a very good finish by following the new few simple steps:

- Cleaning and sanding the 3D printed parts

- Apply few layers of an anti-rust primer (enough to allow for any imperfections to be covered)

- Fine sanding (it depends on the quality you want but 600 grit is already very smooth)

- Spray paint few light layers (rubber coating would give a very nice and soft finish. something like this: )

- Apply few light layers of clear coat to protect the paint.

- Enjoy!

Step 6: Details of Assembly and Files

Unfortunately, the 3D printer broke down and I haven't being able to print the parts with all the final details.

In the next coming days I will finish it and update the instructable to keep everyone up to date with the project.

Step 7: Looking Forward to ...

.... to receive your feedback and check out what modifications and features would the Instructables community will come out with.

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