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We are assigned with the task of designing and building a system to monitor the vitals of four rats simultaneously. Our prototype should be able to detect each rat’s individual SpO2 level, heart rate, internal temperature, and respiration rate; with prominence going in that order. The purpose of this system is to ensure that the rats do not die or wake up while under anesthesia while being scanned in a PET machine. The system should convert, display, and record the vitals information and alert a user if a rat is leaving a normal anesthetized state.
Furthering our understanding of current pulse oximeters and seeing what needs to be changed to adept to measuring rat vitals. We have a human pulse oximeter and we plan on dissecting the signals traveling through the cord in hopes of converting the analog signals ourselves.
We have been doing some testing in hopes of reverse engineering the pulse oximeter clip:
Pin mapping from D-Sub 9 connector:
1 - ???
2 - red wire (to LEDs)
3 - black wire (to LEDs)
4 - Not used
5 - white wire (phototransistor anode)
6 - shielding for white cable (holds white and green wires)
7 - shielding for all wires/protector plate for phototransistor
8 - Not Used
9 - green wire (phototransistor cathode)
If you disable each pin:
1 - dies instantly (LEDs on)
2 - freezes then dies (LEDs off)
3 - freezes then dies (off)
4 - unaffected (on)
5 - freezes then dies (on)
6 - dies instantly (on)
7 - unaffected (on)
8 - unaffected (on)
9 - freezes then dies (on)
tracing resistance between pins:
1&6 connected
2&3 connected (4.2 V DC differential - 2(-) and 3(+) to power)
7 fully independent
(4&8)
5&9 connected (~4.7 to 4.8 V AC when finger in clip
10+ V AC when lights are directly on receiver
1-2 V AC when phototransistor not in range of LEDs)
| Week | Reporting Period Beginning | Activities |
|---|---|---|
| 1 | September 5 | Met with Client. Discussed limitations of current system and began brainstorming possible solutions and tracks for our project. |
| 2 | September 12 | Researched current commercially available systems. Further brainstorming: multiplexing, re-engineer pulse/ox cuff. |
| 3 | September 19 | Found that commercially available options are prohibitively expensive. Began work on understanding human pulse/ox machine and exactly what changes need to be done to work with rats. |
| 4 | September 26 | Acquired Pulse Oximeters from Madison company Sharing Resources Worldwide. LabView coding begins, but unsure of inputs needed. |
| 5 | October 3 | Finding out how oximeter works. Diagrammed inputs, took apart working example. Still need to establish exactly what voltage is in each wire and approximate gains needed. LabView coding needs to be updated with new input information. |
| 6 | October 10 | Preparing for Mid-semester presentation |
| 7 | October 17 | Hooked up the pulse oximeter going through ELVIS so that we can see what each pin is outputing/inputing. Decided to buy new Daq box |
| 8 | October 24 | Worked more on analyzing what the pin outs are telling us. We are unable to find a clear signal and believe we will need to build some preamps and filters manually. |
| 9 | October 31 | Built a preamp to analyze the output we believe is telling us the SpO2. Still lots of noise on channel, started LabVIEW programming for new box |
| 10 | November 7 | |
| 11 | November 14 | |
| 12 | November 21 | |
| 13 | November 28 | |
| 14 | December 5 | |
| 15 | December 12 |
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Project Proposal (Oct 2 2008, 23 kb) |
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Pictures (Oct 2 2008, 1926 kb) |
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Mid-semester powerpoint (PPTX) (Oct 16 2008, 3873 kb) |
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Mid-semester powerpoint (PPT) (Oct 16 2008, 12476 kb) |
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PDS (Project Design Specifications) (Oct 21 2008, 35 kb) |
