Compute Pack Docks
Electrical and Mechanical Design for Docking Solutions
Overview
The Compute Pack Dock projects involved developing two generations. One for the Compute Pack V1 (CPV1) and the other for Compute Pack V2 (CPV2). These docks provided a user-friendly way to distribute mission data to each Compute Pack. They also provided a powerful development platform as the compute packs were networked together and software could be tested without access to tactical radios.
The dock for CPV1 was a quick prototype that repurposed off-the-shelf USB-to-Ethernet adapters and network switch so the Compute Packs could connect over an Ethernet network. I designed a simple PCB to help manage wiring and power regulation/distribution. This dock worked but has some reliability issues and was difficult to assemble.
The dock for CPV2 was more sophisticated. The CPV2 had a dedicated docking port with an Ethernet interface so not USB-to-ethernet adapters were needed. Instead of spending the time and money to build a custom switch, I designed a daughter card that sat on the bottom of an off-the-shelf switch with castellated pads that aligned to the RJ45 connectors. My PCBA managed power regulation, distribution, and high-speed Ethernet signals. I did the schematic, layout, routing, and assembly of the PCBAs. They worked on the first run.
I also handled the mechanical design and assembly, including a retention system that held the CPV2s firmly in place to ensure a reliable connection.
CPV1 Dock assembled and working.
CPV1 custom PCB with JST connectors and two linear regulators.
Product level testing with CPV1 docks.
CPV2 dock PCBA testing. The purple board is the custom daughter card with the switch shown above and the AV power supply below.
CPV2 dock PCBA bottom view.
Castellated holes on daughter card.
PRC-163 radio integration testing with CPV2 docks.
Close of CPV2 dock where you can see the interface LEDs.
Docks packaged up and ready for delivery to SOCOM for a contract.
Accomplishments
- ✓Designed and built PCBAs for both docks, including schematic design, layout, and routing using KiCad.
- ✓Managed vendor relationships for daughter cards and mechanical components, ensuring all parts met specifications.
- ✓Performed board assembly and bringup and delivered fully functional docks on schedule for the SOCOM contract.
Lessons Learned
- •Linear regulators in the first dock generated a lot of heat when the voltage drop was large; I switched to a switching regulator in the second generation.
- •The first dock was a wiring mess and hard to assemble; the second was clean, reliable, and easy to assemble.
- •High-speed signal routing demands tight impedance control and careful layer stackup planning.