oct19meeting
Meeting Goals
Meeting Goals - Get Dale caughtup with progress
- Review this last week's progress
- Determine goals for Design Review
- Review Design Review Expectations
Agenda 1.) We'll start out by reviewing where we are at so far with design ideas. This will get Dale caught up on our thinking about the design. Everyone should be prepared to talk about whatever thier project learning area was. - We'll talk about each of the different sensor types we've thought of so far
- We'll discuss strength's and weaknesses relative to what we've found out
My goal is for this to take about 15 minutes. 2.) After we get through that, we'll talk about the 2 major prototypes, and how they work. Dale can give us some feedback on his thoughts and concerns, so that we can properly address them during next weeks concept design review. 3.) Finally, we will spend a few minutes talking about the Concept Design Review, and see if there is anything specific that Dale would like us to cover. At this point, we should be at about 5:00pm Mountain Time, and we can let Dale go. 4.) After that, we'll move into this last week's efforts. Jen can present on the conversation with the parent, we can hear what Doctor Frostad had to say, we'll talk about how the 2 prototypes went. 5.) We then need to get ready for the Design Review, determine who is talking about what, and review what's necessary for the design review. Please look over the peliminary design review documentation found here. 6.) And, of course, we still are moving full speed ahead on prototypes and designs. So, we'll decide what's up for this next week on prototypes.
Meeting Location 3rd Floor of EP - the libary room for the conference
3:30 Pacific Time
Meeting Minutes Sleep Sound Team Meeting #6 10-19-06 I. Last weeks’ prototypes. A. Scale 1. Colby, Chris and Bart went to the recycling center. - Laid on scales, took normal size and deep breaths. - Normal breathing produced a 0.1lb variation on the scale reading - Deep breathing produced a 0.3lb variation on the scale reading. - These are decent results.
2. Next step - Order a single scale rated for around 15lbs maximum and as accurate as possible. - Use Lloyds’ infant to obtain data on chest movement / applied pressure due to a breathing infant. - Info can later be applied to a grid of smaller pressure sensors. - Also, order an Angel Care monitor and see how it works.
B. Variable inductors integrated into elastic chest straps. 1. Lloyd and Jeff sewed 34 AGW wire, loop fashion, into strips of elastic. -When the remaining leads were connected to an LCR meter and the bands were stretched, a change in inductance was observed.
2. One band was tested at a time. Note: the band with a greater density of loops produced a greater change in inductance. 3. Stretching the elastic produced a considerable change in inductance. 4. How to use these straps to measure breathing. - Build an oscillator circuit (Hartley oscillator) to establish a reference frequency.
- Connect the variable inductor chest strap as a component of this circuit. (The frequency of the circuit is inductance dependant) - The chest movements from breathing will cause a sinusoidal change in the inductance of the chest strap component.
- The oscillator circuit will respond to the sinusoidal change in inductance by outputting a signal that varies sinusoidally in frequency. In short, the output frequency will not be a constant value.
- The output will be sent to an amplifier and connected to a loop of wire running the length of the chest band. This will act as a transmitter. - The signal will be received by the monitor unit and converted to square wave clock pulses by an analog to digital converter.
- This digital signal can then be polled by the controller chip every "X" number of milliseconds for a period of "Y" milliseconds. - The pulses will be counted to determine the frequency. - Since normal breathing should be represented by a constantly changing frequency, the controller chip will set off an alarm if a constant frequency is sensed.
5. Frequency Band Considerations - If at all possible, we want the frequency band of our device to be isolated from cell phone, cordless phone, AM FM signals, etc.
6. For next week -Lloyd and Jeff will develop a SPICE model of the oscillator circuit. If it works, they will build the physical circuit for testing.
II. Report from interview with Dr. Frostad. A. Although he is pessimistic about the effectiveness of SIDS monitors. He does agree with the chest strap sensor idea. B. He gave us a CD about SIDS and infant apnea C. Keep in mind, an infant in deep sleep may not wake up to an alarm, but they will wake up to the voice of their mother.
III. Jennifers’ Interview with Parent A. They had used Angel Care before -Got it from Babies R’ Us for $100 - Worked really well - The sensor pad was a little too small
IV. Preliminary Design Review A. Presenters, topics and tentative speaking time allowances. 1. Everyone - Introductions - 2 min. (give name only) 2. Colby - Needs/specifications/constraints/deliverables - 4 min. 3. Jennifer - SIDS back ground - 3 min 4. Chris? - Sensor overview - 3 min 5. Bart - Underneath design - 3 min
6. Jeff - Summary of project cost / schedule. - 2-3 min 7. Colby - Preferred design idea -
V. Project Cost Rundown A. 3,000 to grad student mentor
1,000 to the shop B. 500 for initial prototype costs
100 for website hosting
400 for printing, reserving rooms, small things
1,500 for final prototype design
1,000 for final prototype build
1,000 for testing
C. Total cost: 8,500 D. Allowed Budget: 9,000
VI. Action Items A. Everyone meet Tuesday 2:30 at BEL 213 to finalize presentation. B. Lloyd and Jeff will work on the oscillator circuit next week. C. Bart will continue to work on the pressure math model. D. Colby will find the change in the diameter of an infants chest as it breaths. F. Bart and Chris will continue to work with the scales.
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