During Summer 2024, I had the opportunity of interning at Lvl Alpha, a startup in India, that focuses on building customisable automated systems for defense measures in extreme, low resource settings. I worked in the Mechanical and EEE team where I was responsible for creating a product concept of a hybrid dongle / tool tracker tag and bringing it into it's mass production stage.
Note : All information has been disclosed with the permission of LvlAlpha.
Using Onshape, I developed and re-iterated multiple designs of the tool tracker and assembled all the components.
I initially rounded the top and bottom corners of the box to enhance the tactile experience. However, this design choice would result in wasted space, as the PCB is rectangular. This led me optimize the design for space efficiency by maintaining a rectangular shape. Additionally, I realized that placing the button directly beneath the power button, rather than having it separately at the top of the casing, would simplify user interaction and streamline the overall design.
I added a slot on the outer casing for the pogo pin charging component and created threading that would fit 1mm starhead screws in the PCB holes for secure mounting onto the bottom casing
I chose a cantilever snap-fit joint for the rectangular box because it provides a secure and reliable connection between the top and bottom casing without the need for additional hardware like screws or adhesives. This joint type is ideal for a rectangular design as it allows for easy assembly and disassembly while maintaining the structural integrity of the casing.
Key Features
Silicone : Part of the top casing for better grip.
Magnetic Pogo Pin Charging: Easy and efficient power connection.
RGB LED: Visual feedback for user interaction.
Built-in Antennas: Seamless connectivity within a sleek design.
Flushed Button Design: Streamlined look, prevents accidental activation.
This device enables wireless communication over varying distances using both Bluetooth for short range and LoRa for long range. In a LoRa mesh network, each device functions as a node, capable of communicating with a central gateway and relaying messages, ensuring extended communication range and reliable message delivery even if a node is unreachable. Bluetooth facilitates data collection from wearable devices, which is then transmitted via LoRa to the base station or another device. The Power and Battery Management System (PBMS) integrates a controller, PMIC chip, LoRa and Bluetooth circuits, LED drivers, ultra-wideband chip, battery monitoring elements, and a lithium cell for efficient power management.
I used this shape as I was thinking of making the height much lower so I could place the battery in front of the circular PCB but for better usabiliy and grip purposes, it might harder for the user to hold it.
The PCB enclosure integrates a magnet for magnetic attachment and a keychain slot for accessibility. Initially, a slot cut for the keychain was used but posed fabrication challenges and potential ingress issues. Given its use in environments with high dirt levels, such as Air Force repair stations, the design doesn't adhere to IP56 standards to prevent contamination.To address these, the design was updated to include a keychain loop integrated into the mold, enhancing durabilit. For the casing connection, I replaced the original annular snap-fit joint (36 mm lip on the bottom, 37 mm lip on the top) with a cantilever snap-fit joint for a more secure and precise fit.
I added a diffusion guard above the hole for the LED to prevent any dust/grime. I also reduced the height of the logo indentation on the top casing to 0.3 cm.
