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Waterproof Handheld Device Redesign Proves Successful

We have extensive experience developing handheld devices.

 

Note: We have been involved in the development of with many hand-held and bench top devices. A number of these have utilized our expertise in micro and macro fluidics, optics, and quantitative spectroscopic detection for analytical analysis systems. These include bio-toxin detectors based upon paramagnetic particles and quantum dot fluorescence, and a blood analyzer using optical absorbance to measure biochemical reaction times. In addition, we have been involved in the design of a military GPS, several models of laboratory pH meters, and a number of lab instruments that involve fluorescence and/or reflectance measurement. We have also developed a number of very successful insulin pumps, ambulatory infusion pumps, and hand-held controllers for implanted medical devices.

 

It is important to work with a contractor who has experience developing a product similar to yours. 
If your goal is to develop a robust and manufacturable product that meets your requirements in the shortest period of time, previous experience is key. Omnica has been helping companies develop their concepts for 29 years, and a number of our group have been in the design and engineering business for considerably longer. Having developed hundreds of products, it’s not surprising that we see many with common features. In addition to more accurate proposal estimates (because we have a good idea of what kinds of challenges we are facing), our experience provides a higher probability of success. 

 

Waterproofing a product can be a difficult goal to achieve.
They offer unique design challenges, given the fact that the usual goal is to pack everything in the smallest possible volume. Also, contrary to what would seem like a reasonable assumption, development of a waterproof enclosure is not an intuitive process. If you haven’t been successful at doing it before, it is very difficult to execute successfully.

 

Waterproofing was only one of the challenges

 

Omnica conducts a pre-production review for a client company.
Not long ago, there was a project that came to us for a pre-production review, which demonstrated the value of our experience. The client company had worked with us in the past, and asked us to review one of their new handheld enclosure designs in terms of waterproofing and manufacturability. The preliminary electronic design was nearly complete, and the process of building the surface mount boards was about to be started.

 

A careful look at the design revealed a number of areas where we could help.
First of all, it was clear that the proposed design would not pass the underwater immersion requirement. The seals would have to be redesigned, the case was too flexible for long-term integrity, and the way the two halves of the case joined would have to be changed. Beyond waterproofing, there was a manufacturability question regarding the placement of an infrared lens in the case.

 

We re-configured the o-ring seal, incorporated some internal shock mounts, and provided interlocking features to stabilize the pager-sized case. Our Mechanical Engineers worked with the customer’s vendors, and redesigned the way the I.R. (infra-red) communication lens installed so the device would be manufacture-friendly.

 

A major issue was the two circuit boards and placement of the specified components.

 

It turned out that we weren't done yet! When our designers looked at the proposed double-sided circuit boards we saw that they were too thick to fit inside the handheld case. To accommodate the boards as the original electronic engineers had envisioned, the eventual case size would need to be 50% thicker than originally planned. The entire case would need to be redesigned if we couldn't find a solution.

 

We reasoned if we could modify the placement of the components, maybe we could “nest” the double-sided companion boards to eliminate the extra thickness. Our approach was to solid-model the boards and their surface-mount components using our SolidWorks™ CAD program. In the computer we could test different placement schemes to see if there was really room to nest the components without physical interference.


We combined stereolithography and electronics


During this process we had ongoing communication with our client company to make sure the proposed placement changes would be okay. When we believed we had the solution, we tested the design changes by building 3-dimensional stereolithography models to confirm the fit. See picture at left. The next-generation boards were configured with the components arranged as we suggested.

 

In the end, we achieved the goals of our client company. 
The surface-mount boards fit closely together without any contact between component leads and traces. The result was a densely-packed product, within the target size range. The device passed waterproof testing on the first round. It is doubtful this project could have been done in the available timeframe without the power of solid modeling and rapid prototyping methods.