And so the serious business begins…
23rd June – 29th June
23rd – 25th June:
With the arrival of more components, we were set to begin assembling our product. A few hours of soldering and crafting later, our first prototype was born! In order to test the load-bearing capability of our prototype, we placed some weighted items onto the support bars (view video V2 here) and were relieved to find the actuators moving smoothly as we had intended. Taking things a step further, we created several foam pieces that could be installed onto the support bars to ensure user comfort.
Next comes the most important part of our project – calibration. Unfortunately, due to the lack of actuators, it was difficult for us to provide height adjustment and support for the aluminium bars. However, with a little creative twist, we used lego blocks (provided by our Captain Manatee) to create temporary support pillars which allowed us to proceed with testing the sensors. Blocks were added to mimic the height adjustment of the linear stepper actuators, though not entirely accurate.
Building our first prototype (becoming chefs and experts at filleting foam)
26th June:
To determine which pressure range and corresponding actuator movement that would result in the highest user comfort, the Manatees decided to recruit some test subjects (ourselves) for the experiment. Our goal is to evaluate the subject’s comfort level over a range and different combinations of actuator heights.
The first part of our experimentation constitutes our test subject lying on a single beam. This accounts for the worst-case scenario whereby the entire head weight is supported by just one support bar. To our delight, the actuators moved steadily even while bearing an entire head’s load (view video V3 here), an indication of our robust design.
Next, we tested the pressure readings by lying on the strips in both supine and lateral positions. We observed that each position had rather characteristic pressure readings. For example, in the supine position, the strip closest to the user’s shoulder had a higher pressure reading because the neck is in a lower position and has more contact with the support strips as compared to the lateral position. The opposite observation is made for the strip furthest from the user’s shoulder. These characteristic pressure patterns among the strips may allow us to determine the sleeping position of the user.
Finally, we needed a way to secure the motors to the base board. This required us to custom print a bracket, which along with the aforementioned function, prevents the motor from shifting as observed during our experimentation. As such, we turned to Autodesk Fusion a second time to create our own bracket. Within a few hours, we were rewarded with our very first 3D print! Other than some minor adjustments, the print had functioned as well as we had intended, and we are looking to print several more of the same piece for other motors too.
Experimentation and more prototyping