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:
- Submit custom PCB and component orders
- Assemble custom PCBs
- Create a pre-flight plan
- Have the HABIP-DAQCS team get the rest of the analog video cameras
- Order APRS batteries
- Set-up the 70cm METEOR receiving equipment
- Test the custom PCB
- 2m transceiver chain testing
- 70cm ATV chain testing
- Finalize a command list
- Develop Pi code for the GPS and APRS
- Figure out how to power the Baofeng radio from our battery
- More APRS testing (and at a distance from the lab)
- Prototype controlling the ATV Transmitter output power
- Test the communication between DAQCS MSP430 and COMMS Pi Zero
- Use APRS to test Ublox GPS module
- Develop Pi code for the transceiver
- Develop Pi code for the temperature and pressure sensors
- Develop the data/command structure between the ground and platform
- Begin parachute work
- Complete antenna ground mounting hinges
- Complete balloon filling plan
- Complete cage assembly
- Testing of cage
- Order aluminum sheeting and mounting hardware
- Order balloon plug, polyethylene boards, rivets, APRS mount
- Primary polyethylene mounting
- Final polyethylene mounting
- We got our custom PCBs and the components to populate them.
- We assembled one copy of our custom PCB. The other one has been started and will be finished in the next phase if the first one is good.
- We created a draft pre-flight plan. It will be reviewed and enhanced for the next phase.
- We now have all 4 analog video cameras. All 4 have been tested.
- We purchased and received APRS batteries.
- We set-up the METEOR Lab to receive 70cm ATV.
- We have started to test the assembled custom PCB. Testing will go into the next phase.
- We performed more testing with the 2m transceiver chain. We set-up a METEOR Lab computer with SoundModem (what runs on the Pi Zero in the platform). We can transmit from our platform and receive it in the lab. We can also receive APRS packets on our platform. We are having some difficulty transmitting from the lab to our platform (to send commands in flight) that we need to look into.
- We also tested the transceiver set-up with the audio going through our custom PCB.
- We tested the 70cm chain with the METEOR Lab receiving equipment set-up. We were able to receive our video transmission.
- The structure components are finished, and semi-assembled. Three would require rework for flight.
- The antenna ground mounting hinges design/prototyping is done.
- The balloon filling plan has been started.
- The cage assembly is done.
- The polyethylene mounting is finalized, but not machined in.
- The major mounting hardware is ordered.
- The materials/alternative manufacturing plan for the second structure (actual flight one) has been made.
Custom PCB UpdateThe 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:
Here is a view through the microscope during assembly:
Here are pictures of the assembled board:
The status of board assembly and testing is shown below:
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
PlatformManufacturing 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.
Antenna RadialsAntenna radial design has been completed and the remainder of the necessary machining will be completed as of week 10.
Test Results SummaryTesting 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.
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.
The I2C addresses from our design page are shown below (the APRS ones do not show up since it was not connected):
Risk and Problem Tracking
The risk management document can be found here.
Problem TrackingHere is our updated problem tracking table:
Here is a pie chart with our updated progress on these problems:
The updated working document can be found here.
Pre-flight PlanBoth 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
Our Gantt chart working document can be found here: MSD II Gantt Chart
- Connor's Phase 8 Individual Plan
- Ian's Phase 8 Individual Plan
- Adam's Phase 8 Individual Plan
- Matt's Phase 8 Individual Plan