Due to its proximity to the wearer’s body, we need to keep the hub’s profile as slim as possible. The result will hopefully be a clear plastic enclosure roughly the size and thickness of a pack of playing cards. A similar sized power bank will power the hub located in one of the wearer’s pockets. The various sensors will have a similar look, only they’ll be around the size of a custard cream biscuit. I know right? very precise.
I soldered the multiplexers directly to the breadboard. Currently the wires are chubby boys, I’ll eventually replace them with something much thinner, but for now I’m using these flexible silicone wires for testing as they are easy to manipulate while I’m tinkering with the design. I made the error of using lead-free solder which made a real mess of the soldering on my Pi Zero. Note-to-self: use more forgiving lead-based solder from now on, it’s not worth the pain and suffering. Initially, I was hoping to include some connection ports inside the housing to allow for easy disconnection of data cables, but space is looking a little tight, so it may be easier to solder directly to the board.
To keep things nice and frugal we’ll be repurposing clear perspex material from redundant COVID pandemic barriers and other off-cuts from previous maker projects. We can then use the mounting points of the various components to establish fixing holes for the screws that will hold enclosure together. I’ll be combining these with some metal stand-off spacers for structural integrity. This should create a rugged but nifty-looking hub that is easy to disassemble while also showing the inner workings for demonstration purposes. Plus, clear gadgets look cooler. Facts.
Once the most suitable orientation and location for the hub is finalised, cutouts will be made around the edges of the enclosure to allow for the various data cables to connect to the hub. I’ll bodge this for the first iteration and then update the laser etching diagrams for later versions. The hub itself will either live in the wearer’s left/right pocket just below the ribs or placed at the base of the spine, I haven’t quite decided yet. I’m leaning more towards the pocket location for both ease of access and movement flexibility, providing the wearer with the freedom to roll around on their back while wearing the system. There’s some more thinking needed to protect the back spine sensors.
Speaking of the sensors, their custard cream sized enclosures will comprise two different designs, 14 smaller versions for the majority of the suit, and two with extra space for a USB-C port. The larger enclosures will be situated on the wearer’s forearms allowing for the motion capture gloves to receive power from the main suit via USB. Processing and transmission of hand motion data will be handled within the gloves themselves through dedicated Raspberry Pi PICO controllers, this will help to more evenly distribute data collection and transmission across three devices, as the Pi Zero just wouldn’t be able to reliably handle the whole lot.
Our workshop is waiting for a replacement part for the ventilation system, so laser cutting the prototype enclosures is delayed for a week. I’ll hopefully get to test this out in the coming days. Until then, I’m going to look into a reliable way to remove the STEMMA/QWIIC connectors from the motion sensors using a soldering iron. Initially I was going to use these, but crimping connectors to the ethernet cables is so fiddly that I’m thinking it will be easier and more reliable to solder the wires directly onto the contact patches of the sensor’s PCB, while simultaneously reducing the overall thickness of the sensors once the connectors are removed.
Wish me luck…