wiki/ capstone2009/ blogs/ ScottSchuehle
  1. Weekly Progress Reports
    1. Weekly Progress Report, 5/30/09 - 6/5/09
    2. Weekly Progress Report, 5/23/09 - 5/29/09
    3. Weekly Progress Report, 5/16/09 - 5/22/09
    4. Weekly Progress Report, 5/9/09 - 5/15/09
    5. Weekly Progress Report, 5/2/09 - 5/8/09
    6. Weekly Progress Report, 4/25/09 - 5/1/09
    7. Weekly Progress Report, 4/18/09 - 4/24/09
    8. Weekly Progress Report, 4/11/09 - 4/17/09
    9. Weekly Progress Report, 4/4/09 - 4/10/09
    10. Weekly Progress Report, 3/28/09 - 4/3/09
    11. Weekly Progress Report, 3/20/09 - 3/27/09
    12. Weekly Progress Report, 3/7/09 - 3/13/09
    13. Weekly Progress Report, 2/28/09 - 3/6/09
    14. Weekly Progress Report, 2/21/09 - 2/27/09
    15. Weekly Progress Report, 2/14/09 - 2/20/09
    16. Weekly Progress Report, 2/6/09 - 2/13/09
    17. Weekly Progress Report, 1/30/09 - 2/5/09
    18. Weekly Progress Report, January 26 - January 30 2009
    19. Weekly Progress Report, 1/19/09-1/23/09
    20. Weekly Progress Report, 1/12/09-1/16/09
  2. Project Log
    1. Log Entry, 3/12/09
    2. Log Entry, 3/3/2009
    3. Log Entry, 2/24/2009
    4. Log Entry, 2/18/2009
    5. Log entry, 2/4/2009
    6. Log Entry, 1/29/09
    7. Log Entry, January 27, 2009
    8. Log Entry, January 22, 2009
    9. Log Entry, January 16th, 2009
  3. Meeting Notes
    1. Meeting 13 Notes: April 3, 2009
    2. Meeting 12 Notes: March 27, 2009
    3. Meeting 11 Notes: March 20, 2009
    4. Meeting 10 Notes: March 13, 2009
    5. Meeting 9 Notes: March 6, 2009
    6. Meeting 8 Notes: February 27, 2009
    7. Meeting 7 Notes: February 20, 2009
    8. Meeting 6 notes: February 13, 2009
    9. Meeting 5 notes: February 6, 2009
    10. Meeting 4 notes: January 30, 2009
    11. Meeting 3 notes, January 23, 2009
    12. Meeting 2 notes, January 16, 2009
    13. Meeting 1 notes, January 16th, 2009

Weekly Progress Reports

Weekly Progress Report, 5/30/09 - 6/5/09

Last Week

This Week

Next Week

Weekly Progress Report, 5/23/09 - 5/29/09

Last Week

This Week

Next Week

Weekly Progress Report, 5/16/09 - 5/22/09

Last Week

This Week

Next Week

Weekly Progress Report, 5/9/09 - 5/15/09

Last Week

This Week

Next Week

Weekly Progress Report, 5/2/09 - 5/8/09

Last Week

This Week

Next Week

Weekly Progress Report, 4/25/09 - 5/1/09

Last Week

This Week

Next Week

Weekly Progress Report, 4/18/09 - 4/24/09

Last Week

This Week

Next Week

Questions

Weekly Progress Report, 4/11/09 - 4/17/09

Last Week

This Week

Next Week

Questions

Weekly Progress Report, 4/4/09 - 4/10/09

Last Week

This Week

Next Week

Key Questions

Weekly Progress Report, 3/28/09 - 4/3/09

Last Week

This Week

Next Week

Questions

Weekly Progress Report, 3/20/09 - 3/27/09

Last Week

This Week

Next Week

Weekly Progress Report, 3/7/09 - 3/13/09

Last Week

This Week

Next Week

Questions

Weekly Progress Report, 2/28/09 - 3/6/09

Last Week

This Week

Next Week

Weekly Progress Report, 2/21/09 - 2/27/09

Last Week

This Week

Next week

Questions

Weekly Progress Report, 2/14/09 - 2/20/09

Last Week

This Week

Next Week

Questions

Weekly Progress Report, 2/6/09 - 2/13/09

Last week

This week

Next Week

Questions:

Weekly Progress Report, 1/30/09 - 2/5/09

Last week

This Week

Next Week

Weekly Progress Report, January 26 - January 30 2009

Last Week

Researched the functionality of the current power switch design. From last meeting, I now have a pretty good understanding as to what purpose the switches serve in the APS, and the reason for redesign. Essentially the switches are power switches with circuit breaker capability. 4 more switches need to be added to the current APS and the design of each switch should be simplified.

This Week

Studied the LV2b APS component design in depth, on the level of each component. I now have a very solid understanding of the fundamentals of what is going on in the circuit, namely the power switches. Searched the internet for potential alternative ICs to use. Was a bit overloaded since I had a midterm this week so I still need to transfer my log entry from logbook to wiki.

Next Week

With a pretty good understanding of how the switches work, along with the newly posted requirements, I will look for IC's which can perform the same functionality reliably, meeting the specs, and perhaps be implemented in a simpler way. Will produce a decision matrix, and hopefully be able to begin redesign of the switch network.

Questions/Problems

Aside from the newly posted requirements, I still do not know the specifics of what the specs of a new IC need to be. From the documentation I have gathered the following:

Weekly Progress Report, 1/19/09-1/23/09

Last Week

This Week

Next Week

Key questions and discussion topics

Weekly Progress Report, 1/12/09-1/16/09

Last Week

This Week

As for the LTC communications link, with the implementation of the Universal Rocket Bus, how is this portion of the project affected?

Hopefully we'll have time to address each of these questions at the next meeting.

Next Week

Project Log

Log Entry, 3/12/09

Log Entry, 3/3/2009

Mission agenda for the evening

* Look over alternatives to the LTC4007
* If we can't find any alternatives, we'll talk about how to redesign the LTC4007
* Also talk a littl e more about system "glue"

Ideal Diode stuff

See Umbilical Spec Page at this link for details: Umbilical Specs

Log Entry, 2/24/2009

Other Chips

Log Entry, 2/18/2009

Follow this link to the switch spec page:

Switch Specs

Log entry, 2/4/2009

Manufacturers searched and relevant products

Log Entry, 1/29/09

Notes from APS Component Design Spec

Log Entry, January 27, 2009

New Design Requirements Added to Wiki: For my power switches, requirements are as follows:

Power Switches

With these requirements, the redesign becomes much easier since I now have a good idea of what I'm doing here. This week I will research power switch IC options: Available products, their features, etc. the next step will be a decision matrix which we as a group will probably need to evaluate.

Log Entry, January 22, 2009

My mission this week has been to study the existing power switches on the APS. The main questions driving my research are:

Overall Functionality

Figure 1 below is a copy of the power switch section of the current APS. Figure 2 shows a closeup of one of the power switches and external circuitry.

Figure 1: Power Switch Section of APS

Figure 2: Power switch close up

Figures 1 and 2 are both taken from the EAGLE schematic for the actual LV2b APS. In the APS component design spec. these circuits are explained as power switches for system loads. My first question becomes: What are the system loads here?

The external circuitry in the design shown in fig.1 is for the most part to control how the switch behaves during fault conditions such as overcurrent, i.e. the ability for the switches to act as breakers. The datasheet for the 1154 contains this exact circuit so that is where I will find more in depth info. as to the functionality of each part of this circuit.

I also am curious as to how the power switches here on the APS differ from those on the recovery node. Figure 3 shows one of the power switch circuits from the component design spec of the APS.

Figure 3: Power Switch from recovery node

The above figure, while rather unclear, shows that recovery switches are not at all the same as those for the APS. The switches on the pyro node are critical in the functionality of the igniter circuits, which I assume have very different power needs, etc. These switches, which utilize IR2118 ICs are also on the agenda for redesign and so I will be exploring them later.

In Depth functionality

The LTC1154 datasheet will no doubt provide much useful information about how these switch circuits function. The data sheet can be viewed by clicking the following link: http://psas.pdx.edu/AvionicsPowerSystemLv2/lt1154.pdf

As stated, the circuit shown above in figure 2 was taken directly from the datasheet. To understand how this circuit works, studying this datasheet will most likely prove useful. Parts of this datasheet will be repeated here to aid in my understanding of these circuits. Figure 4 shows a pin diagram for the ltc1154.

Fig 4: LTC1154 pin diagram

A brief description of each pin and my understanding in the APS follows:

Log Entry, January 16th, 2009

As is stated in the meeting recap below, the week following the first meeting was dedicated to researching the history of the LV2 rocket and its design over the years. Specifically, since I'm going to be doing what I am imagining as a good deal of work on the recovery node, understanding this system is where I focused most of my attention over the last week.

I spent a good deal of time pouring over the Avionics Team page on this Wiki which proved relatively informative. The major problem I encountered during my research is that it is not entirely obvious what documents are out of date. Thus, it is sort of unclear whether the version of the node I am attempting to understand is the most recent version.

Below is a list of helpful documents and wiki pages I encountered over the week as well as links to those pages/documents:

The above list of documents and wiki pages is a small sample of all the material available on this topic, so obviously more research is necessary. At this point I think it's a matter of finding out exactly what my goals in this project will be, and then the necessary research will be greatly narrowed down.

Recap of important questions for next meeting

Meeting Notes

Meeting 13 Notes: April 3, 2009

At this point, Andrew feels we're getting too far behind. Firmware needs to get things happening so we can begin overall system integration

Meeting 12 Notes: March 27, 2009

Meeting 11 Notes: March 20, 2009

Was unable to attend this meeting due to the fact that I had a final project in one of my classes to finish. Will be checking other team members' blogs for meeting info

Meeting 10 Notes: March 13, 2009

Andrew brought up the fact that we're a little behind as a group as far as getting EAGLE schematics and board layouts finished. May have to edit the project timeline accordingly.

SPI Interface

Jeremy

* At the point where he can program the LPC
* Also able to do some work with freeRTOS

Dave

Ai Ling

Me(Scott)

Ken

Other Topics Discussed

Meeting 9 Notes: March 6, 2009

Meeting 8 Notes: February 27, 2009

Pressure test possibly next Friday in place of usual 2:00 meeting

Mike and Jeremy

Some EAGLE notes

Dave and I

Meeting 7 Notes: February 20, 2009

Dave

ME

Ai Ling

Mike and Jeremy

Ken

Meeting 6 notes: February 13, 2009

Battery

* <www.all-battery.com/37volt-4000mah15cli-polycell.aspx> 
* At this point this looks like the top choice, if so will buy
* need datasheet
* no cahrger-chips found yet
    *  This is a key part of design so Dave and i need to get to work on this

Umbilical

Shore power diagram

Firmware

* Need to discuss what it should do
* Andrew, Mike and Jeremy will be getting together
* Free RTOS running
* Also need to look into test harness for Ai Ling

Sensors

* HUB chip chosen by Sarah
* High speed stuff irrelevant at this point because using PWR PC, but spped will matter in the future
* Will look into developement board for HUB
* check out ALCOR
* 80XL02 accelerometer chosen (good to 70g)

Power Switch stuff

* Tim and I did a little calculating and discussed thermal characteristics of transistors
* With what we talked about, i should be able to do calculate component values
* We also went over the "constant power engine"

Also look for developement boards for our chips

Meeting 5 notes: February 6, 2009

Important Topics

Project Updates

Some notes on IC packages:

Power switch discussion

Meeting 4 notes: January 30, 2009

For Power Switch:

Meeting Minutes

Meeting 3 notes, January 23, 2009

Documentation questions:

Grading Criteria

Side Note

Dan/Dave from the Rocket Group might want to change backchannel serial bus to CANbus * this shouldn't affect our current assignments * this could eliminate the 8:1 MUX on APS

Group Progress/Questions

Some SPS Notes:

the system essentially consists of power being switched on and off producing a square wave. This square wave is then filtered through an inductor which produces a "sawtooth" triangle wave. However if the power is switched off for too long the system enters what's known as "discontinuous mode" which introduces noise into the system, among other things.

Solution: make inductor bigger, which then increases saturation current * this takes up board realestate

Power Switch notes (for my current portion of project)

Meeting 2 notes, January 16, 2009

Ideal Agenda

WPRs

The URB

Getting Started (Task List)

David

ME (Scott)

Ai Ling

Ken

Mike and Jeremy

Notes on protected switches

Meeting 1 notes, January 16th, 2009

This is my first official entry into my "electronic project notebook." We had our first official capstone meeting January 9, 2009 (last Friday) where we discussed the following:

Logistics

Project Specifics

Before the next meeting