Mindset Update - February 2018
February (and part of March) focused on our latest prototype batch - read on to see lots of great pictures!
Jacob Flood, March 24, 2019
February bled into march as we pushed this update a few extra days in order to show you pictures of our latest prototype batch. This batch looks incredible so far - we’re really excited to show you all the pictures we took while assembling them.
The latest prototype batch’s assembly went well – you can read about the specifics, and see tons of great pictures below. We’re not quite done the assembly, so we’ll continue to update this post next week with more pictures of the final units.
So far, the parts look great and assemble well. We had a few issues with the upper band being too stiff (which we temporarily fixed), and with our electronics software (which we hacked together a solution for). Neither of these will affect our mass production units. We’re waiting to receive a few more parts (namely the electrode band) to assemble the final units.
We’ll post more pictures, and videos of the product in-use once the assembly is done and shipped to the Montreal office! In the meantime, we’ll continue working towards our next batch, which should arrive late April/early May. This will be our last pre-shipping batch.
Finally, we put together a survey to get your feedback on the user experience of the product – please take the time to fill it out: https://goo.gl/forms/yLB8mvzOJYZ5tyIr1
We need your help designing our app!
In parallel to the hardware developments below, we’re taking this month to undergo a UX design process: consolidating what we’ve learned building and testing the app, to create the final ship-ready user interface for the software.
In order to make sure the product fits your needs, we met with several backers last week to dive into questions about work habits, focus environments, and general expectations for the product.
We also put together a survey that we’d like all of you to fill out. Please take the time to fill out our short (~3min) survey, to help us design the product to fit your needs: https://goo.gl/forms/yLB8mvzOJYZ5tyIr1
Thank you so much for your help!
Last month, we discussed ordering all the parts to build four additional prototypes to decrease the risks associate with tooling – our pre-DV validation batch. We expected those units to be ready for assembly early March. However, because of additional delays due to Chinese New Year, as well as some engineering issues, the assembly of the prototypes was completed last Friday, with the remaining subassembly coming next week.
That said, we have a LOT of pictures below to guide you through the assembly and describe all the work that was done over the past month. We’ll also update this blog post next week with the final steps of the assembly that are still in progress.
With this batch done, the tooling process will yield a subsequent DV batch in late April/early May. This timeline will be described in more detail below
Following Chinese New Year – officially the first two weeks of February – there has been a slow but steady pickup of business in China. We received most of the mechanical parts in time for the assembly scheduled for the first week of March. You can see below pictures of the main parts as we received them:
The ear-cups was the first piece, and turned out absolutely gorgeous. As you can see, the buttons are protruding from the ear-cups more than in the previous iteration, which makes for a more distinct touchpoint. When all assembled, the center button is mildly lower than the other Volume UP/DOWN, which makes it easier to locate when wearing the headphones.
You may also notice the small slot below the center of the ear-cup. This slot was designed for better ANC functionality. In this iteration, slight alterations to that slot were made to better hide it and to accommodate for cabling constraints on the inside.
The arm bands were next, and came out beautifully as well. We worked closely with our suppliers to match the color of the aluminium arms to the plastic ear-cup as closely as possible - they did a wonderful job at achieving this, despite the differences in low-batch and large-batch manufacturing. The anodized, sandblasted finish is reminiscent of the finish on the darker MacBooks.
As described in previous updates, the curvature of those arms has been changed recently to improve the fit on your head.
The clips and endcaps are relatively untouched since last iteration. The finish might change in the future to swap the painted logo for a laser etching – a small change that’s been anticipated, but low priority from the start. The right and left metal clips have been adapted to allow for the flat cable assembly to pass through, and the parts were color-matched with the arm bands and ear cups.
These earcup parts cover the speaker, and create the cavity in which your ear’s fit when you wear the headphones. They are also the parts most responsible for the audio tuning – as a result, there have been quite a few changes to this part recently. Since the last prototype, we worked closely with our acoustic engineering and went through 4 full revisions of this part to reach our required audio standards. We’re excited about the results - with the last version, many of the people we tested with confirmed that our headphones sounded better than the reference units we compared them to.
Several minor changes were done to the previous design to improve the assembly, reliability and cost of the electrodes. Since the beginning, the design of the electrodes has posed two major challenges that we now believe are solved:
How to make a high-quality electrode cheap enough to be used in a consumer product
How to design those electrodes ergonomically to keep everything comfortable for extended use
In the academic community, several different types of sensors have been proven to work effectively for EEG. Unfortunately, these electrodes tend to be expensive (often ~$40 each), and often either require conductive fluid (wet electrodes) or cause significant discomfort. Whereas some researchers are working using different materials like conductive silicone to overcome these problems, we approached the problem differently.
Instead, we asked ourselves: how can we use what we know works, and adapt it to make it cheap and comfortable? The result is what you see below: our design is up to 50 times cheaper than similar quality electrodes, which make it viable to use in consumer devices.
Over the previous few weeks, we have tested the headphones around our coworking space in Shenzhen. The results have been amazing: our user experience tests have established that the headphones are quite comfortable.
The overwhelming consensus is that while users can still feelthe sensor contact, it doesn’t feel uncomfortable and they forget it over time. Essentially, it feelsdifferent, but not bad. The analogy we heard often is that of wearing a watch: the contact feels strange at the beginning, but when you get used to it you simply forget it is there in the first place.
As we move into production, there will be slight tweaks to this design to allow for easier manufacturing at high volume, and to optimize the color, material, and finish to match the rest of the design. That said, we are incredibly happy with how well these turned out, nearly a dozen iterations later.
Lately, the upper band has been the trickiest part of the product to develop. The problem was straightforward: the industrial design we initially conceived turned out to be quite difficult to translate into a functional product. The main issue with the design of this part was to get the proper shape and clamping force, while allowing for scalable production.
Through normal use over the lifetime of the product, the upper band of the headphones repeatedly bends - overtime, this causes the plastic to soften. This causes the clamping force of the headphones to diminish over time, which would hurt the audio, ANC, and ear cup electrode performance.
For this reason, it is necessary to use at least one piece of metal to support the plastic, and extend the lifetime of the headphones. The part shown above is used for that purpose. It is also used as a mounting point for EEG electronics on the white bracket. The mechanical tuning of these units – making sure they complement each other and bend together in the right way – required several iterations to get right.
One of the key changes since the previous batch of prototypes was to the part shown above. Those pieces allow the aluminum arms slide in and out, and give the headphones their distinctive asymmetrical shape.
In the latest iteration, they were changed from two parts that clamp together to a single part. While this change increases the cost for the molds, it also highly increases the reliability of the part and simplifies the assembly. Reliability is crucial on this part, since it determines how well the arm will slide in and out. Spoiler alert: it feels really nice and smooth.
Our engineering team also made small modifications to this part to allow room for the flat cable assembly, which you will see below.
The image above shows one of the mechanical sub-assemblies. Our engineering team at the factory did a fantastic job at simplifying how these parts fits together. In particular, on the white brackets you can see that the region in the middle – with two long slits – now has space for the flat cable assembly to rest. After the cables are installed, this whole assembly is wrapped in black fabric, giving the whole a sturdy, professional feel.
The picture above shows the assembly right before it was ready for the upper band fabric wrapping.
At this stage, with the first version of this batch, we encountered a problem: our tests indicated that upper band was much too stiff. Our next batch will require us to change plastic compositions in order to get the right stiffness for the same shape (a small change that should cause no issues). In order to allow us to use this batch for tests however, we needed to get creative.
We found two solutions that were implemented right away:
First, we removed the screws between the white bracket and the black upper band. In this way, the steel band flexes to provide the stiffness, while the plastic piece “floats” around it. This is a temporary hack that allows us to finish testing and move forward, but required us to temporarily reinforce the steel band to achieve the right stiffness (an aesthetically unappealing solution).
In order to make a functional unit that doesn’t require additional support – for beta testing purposes - we developed a second solution: over-molding silicone at both ends of the black plastic part, and manufacturing a thicker spring-steel band that would provide a higher clamping force. With this change, we should be able to produce some of the batch’s prototypes fully-finished, ready for user testing.
Despite the setbacks, we are now ready to finish the assembly. This picture above demonstrates the partly assembled headphone band, ready to be wrapped in the black fabric.
After wrapping the fabric, the sub-assembly looks like the picture above. You can also see several finished ear cushions wrapped in fabric surrounding the headphones.
At this point we would typically assemble the outer part of the ear-cup, and then add the electronics. However, at this phase we encountered our second issue: the electronics boards from our manufacturer were still being tested for audio quality while the rest of the headphone was being assembled. In addition, we didn’t receive the lower band (with electrodes mounted) in time for the assembly. As a result, we’ve moved forward with prepping our next batch while we wait for these parts – we’ll update this post with new pictures once the assembly is finished.
Although the assembly isn’t fully complete, the headphones still feel quite comfortable. The final assembly will take place this week, adding in the lower band (with the electrodes), the electronics, and adjusting for the force of the external wire on the ear cup pivot.
Once that’s done, we’ll ship the prototypes to the Montreal office, where we can share videos of the whole product – audio, EEG, and app – all working together!
In parallel to the mechanical parts, we produced a small batch of the EEG, Audio, and Bluetooth electronics as well. Unlike the mechanical parts, the way these boards are made nearly identical as compared to mass production (except for the price, of course).
The PCBs above are the brains of the EEG processing (pun intended). The data coming from each sensor is first pre-processed, and then sent to this board for further processing and conversion to a digital stream. In the above photo, the boards were being functionally validated outside the headphones, before assembly.
In addition to the main PCB, there are several other boards used to process the EEG signal in various parts of the headphones. Those ensure that the signals we record are not contaminated with ambient noise, and therefore that the data being collected is accurate.
While manufacturing one of the boards, we encountered a small software glitch in our PCB layout tool. In releasing the purchase order for production, the software created a part lists containing components that weren’t up to date for this version. As a result, when it came time to assemble the components on the boards, one of them did not fit exactly.
Instead of delaying the assembly, we decided to assemble all the other components normally, and to hack together the missing components by hand. While the inside of the headphone in this batch will not be 100% representative of the final process, it will allow us to perform the necessary tests to validate this batch, and skip straight to the production as intended. While this was more work than expected, by proceeding in this way we minimized the potential delay by several weeks.
These issues are the type that have previously caused unintended delays. Often at this stage, all we can do is minimize the impact that these unpredictable events have on the schedule - we’re fortunate that in this scenario, the problem was fully recoverable and won’t impact our final timeline.
The purpose of those prototypes was to run functional tests, ensuring that all our requirements are met. In the process of assembling the prototypes, we isolated a few potential issues that were resolved - the stiffness of the upper band and electronics file were among the most significant. As of writing, we’ve already implemented corrective measures for these issues.
The tests that we will be conducting as the assembly is finished next week aim at validating the following:
There are no major issues with the mechanical assembly, and how the electronics fits inside.
The headphones fit on both our test jigs for head size, and a sample of real users.
There are no major electronics issues with the whole system wired together.
The EEG data is clean and streams properly to multiple kinds of devices.
The audio response meets our standards.
The active noise cancellation meets our standards.
The Bluetooth User Interface meets our requirements.
Once we have validated those seven points, which represent the core features that can impact the design of the hardware, we will be freezing the mechanical design. With the mechanical freeze will come the molds. We hope this freeze will happen by the end of the month, in order to deliver a next DV batch by late April/early May.
While the focus of this month has primarily been coordinating the prototype assembly, we also did a lot of work reviewing the Bluetooth user interface – the series of button presses and code snippets that allow the headphones to pair with a computer or phone. We hope to be able to share more details on the final UI in the next few weeks.
In addition, we started working on the packaging design for the headphones. We will be soon able to provide renders, and possibly prototypes boxes to show what the packaging will look like.
We also finished the second iteration of our neuro-adaptive music, and have been using it internally for two weeks while we work. So far, we’re incredibly impressed – we’ll be receiving V3 in two weeks, at which point we hope to freeze the design. We’ll share videos of this feature working with the headphones in the coming weeks.
We’ve made some incredible progress this month, and we’re eager to bring that forward into our next mass production batch. We’re a few small steps away from shipping - we can’t wait to culminate this part of our journey together, and take our step into using Mindset to better our lives.
That’s all for now! As we mentioned earlier, we’ll continue updating this post with pictures as we finish the assembly.
Upon request, we’ll also share videos of the headphones in-use once we finish this batch. We’re excited to show you the fruits of our labor, so stay tuned for that!
Lastly, please take the time to fill out our UX survey to help us optimize our app for your work habits: https://goo.gl/forms/yLB8mvzOJYZ5tyIr1. We really appreciate your effort!
Lots of love,
- The Mindset Team