P17104: HABIP-COMMS
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Integrated System Build & Test

Table of Contents

Team Vision for Integrated System Build & Test Phase

We focused on building the structure and assembling our custom PCB this phase. As a result, we did not get all of the testing and software done that we wanted to get done.

Goals for this phase:

Accomplishments:

Custom PCB Update

The board (2 copies) has been ordered and received. One copy is fully assembled and the other is partially assembled. We are testing the assembled board (see Test Summary section).

The final schematic can be found here: Main COMMS Board Schematic

The final custom PCB BOM can be found here: Main COMMS Board BOM

In hindsight, we should have printed more information (like label what a connector is for) on the silkscreen layers.

Our gerbers can be found here: zipped gerbers

The generated plots by Advanced Circuits (board manufacturer) can be found here: Advanced Circuits Plots

Here are pictures of the bare board:

Bare Board Front

Bare Board Front

Bare Board Back

Bare Board Back

Here is a view through the microscope during assembly:

Board under Microscope

Board under Microscope

Here are pictures of the assembled board:

Assembled Board Front

Assembled Board Front

Assembled Board Back

Assembled Board Back

The status of board assembly and testing is shown below:

Board 1 Progress

Board 1 Progress

Board 2 Progress

Board 2 Progress

Here is a link to a video that shows some of the moments that went into board assembly (for both teams): YouTube Video

Mechanical Side Update

Platform

Manufacturing of the first platform subsystem is complete - with work on the second, and idealized final, subsystem to begin 03/31/2017. Although complete, to be flight ready, three of the polyethylene layers would require rework as they do not fit sufficiently within the caging. Layer mounts have not be machining into the layers and will not until final wiring confirmation is given - which is beginning week 9/10.

Components for the secondary platform have been ordered and machining of those components will also begin week 09.

Platform

Platform

Antenna Radials

Antenna radial design has been completed and the remainder of the necessary machining will be completed as of week 10.
Radials

Radials

Test Results Summary

Testing has been mainly done on our Communication Host Board. During board bring-up, we tested subsystems as we assembled the various sections. We started with the 11.1V power system, starting with the 12V boost circuit, and following with the 5V and 3.3V supplies that are also generated from this system. These circuits were tested to be fully functional. Moving on, we assembled the 7.4V power system, and tested the 5V and 3.3V power rails that were generated. These circuits were also tested to be fully functional. Testing was done by powering the circuits using a current limited power supply, and measuring the output voltages on board test-points using a multimeter. Voltages were within acceptable ranges.

Knowing that all the power circuitry is fully working, we assembled the 2m audio connectors and verified that 2m transceiver worked through those audio connectors. Finally, we assembled all the subsystem ICs and surrounding circuits, as well as the board connectors, and began testing all the subsystems.

The Pi was placed in the board, all the cameras were hooked onto the board, the OSD was powered and supplied with an input video connection, and the ATV transmitter power and video were connected. All of these parts make up the video chain. An image of this assembled system is shown below. Random connectors were used, once we verify operation, we will begin assembling connectors.

Video Chain Setup

Video Chain Setup

The video chain is fully working. We are having issues with video quality at the moment, but we believe the receiving equipment or the test environment are to blame. As designed, we are able to toggle power to each of the cameras, control the video multiplexer, and toggle power to the OSD. Python test scripts have been written to control these IC's through the Raspberry Pi's GPIO.

Finally, we verified that all (4) I2C devices (temperature sensor, pressure sensor, GPS, and digital potentiometer) are present on the i2c bus. Further testing will be done to make sure the devices themselves work, and for the digital potentiometer, interfaces well with the ATV transmitter.

i2c Devices

i2c Devices

The I2C addresses from our design page are shown below (the APRS ones do not show up since it was not connected):

I2C Addresses

I2C Addresses

Risk and Problem Tracking

Risk Management

Risk Management

Risk Management

The risk management document can be found here.

Problem Tracking

Here is our updated problem tracking table:
Problem Tracking Table

Problem Tracking Table

Here is a pie chart with our updated progress on these problems:

Problem Tracking Wheel

Problem Tracking Wheel

The updated working document can be found here.

Pre-flight Plan

Both teams (P17104 & P17015) have started to develop a pre-flight plan for launch of the high altitude balloon and payload (our platform). A draft of the document can be found here: pre-flight plan draft.

Plans for next phase

Team Plans

 Gantt Chart for Next Phase

Gantt Chart for Next Phase

Our Gantt chart working document can be found here: MSD II Gantt Chart

Individual Plans


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