MaSCOT Report, Part 3: The Companion Board

TL;DR: I ended up needing to to design a micro-based “companion board” which handles power-on, watchdogging, out of band comms, and LED light control for the Jetson. The details can be found on GitHub.

See also part 1 and part 2

A primary concern for me was ensuring the system was as usable as possible while inside the housing. Opening and closing the housing is time-consuming and somewhat risky in terms of getting a repeatable seal. Unfortunately, the ethernet-only architecture severely limited my options for out-of-band communications to the system. That is, if the Jetons failed to boot, there would be no ethernet, and I’d be hosed.

Sample MaSCOT Data

Oct 27, 2016: I’ve moved the contents of this page to a more permanent location

{:.center} Left sample image

MaSCOT Report, Part 2: Mechanical Design

As described in part 1, the prototype system architecture is:

{:.center} System block diagram

The mechanical design was the one element I did not handle myself. I worked with a mechanical engineer at APL to design an inexpensive, easy to machine shallow water housing with enough space for the Zed and Jetson. The final design consists of a single 12" x 12" block of Delrin with a single cavity hogged through it. The front and back faces have o-ring seals and tapped holes for retaining bolts for the endplates, and a series of top-to-bottom through-holes along the sides provide mounting points.

I need to write a final report for the MaSCOT project during 2016. I thought drafting the report as a series of blog posts would kill two birds with one stone…

This is an introduction the Marinized Stereo Camera Operational Testbed (MaSCOT), an internal R&D project supported by the APL Science and Engineering Group (SEG). The project had multiple goals:

to procure one or more stereo vision cameras and package them for shallow-water underwater testing;
to any sort of machine vision camera at all for use underwater (which is mostly redundant with one); and
to support my serious engagement with at least one Open Source SLAM program – there is such a diversity of code available, I felt it was better to incrementally improve and existing codebase than start from scratch.

Besides hardware costs, the project supported a small amount of time for a mechanical engineer at APL to design and construct the camera housing. My time was supported under the APL postdoc program.

Benchtesting MaSCOT

[Apologies that this is the first post about MaSCOT. I’ll try to keep up a development blog and backfill with add’l project notes and resources. Maybe.]

The full MaSCOT system has been assembled and is ready for tank testing.

Jetson temperatures

I ran the sealed system on the desktop for the first time last night. While it was on I recorder internal air temperatures using the Bosch BMP280 on the companion board, plus the Linux ACPI temperature values.