Given the cheapest price I could find on the ResMed S9 Oximetry Complete Kit was about $1000, with internet advertised prices at $1325 ( http://www.cpapusa.com/cpap-sleep-apnea ... T2822.html ), I decided to attempt the modifications that casadelane originally posted in this thread:
( viewtopic.php?f=1&t=50805&start=45 )
I modified the ResMed Oximetry Adapter to work with a standard PS/2 mini-DIN 6 pin cable. I again used many of the ideas that casadelane described in his great post. Unfortunately, I am unable to access his attached images. I wrote these instructions so that no pictures are required. I can post pictures to this thread at a later time.
The PS/2 cable is exactly the same cable used for non-USB keyboards and mice. I decided to use this cable given its availability at most computer stores and the option for an extra extension cable once you have completed the project for additional length. You can however use whatever connectors you desire such as the Lemo connectors. Cut the 6 foot PS/2 extension cable in half. One half will have the female connection which I used to attach to the ResMed Oximeter Adapter. The other piece will have a male connection which I used to attach the Nonin 3012 Oximeter device.
- ResMed Oximeter Adapter purchased from http://www.cpapusa.com for $225 (free shipping). I got a better deal than the advertised price of $279. Ask Blake for their best price.
( http://www.cpapusa.com/cpap-sleep-apnea ... T2501.html )
The ResMed manual can be downloaded at:
( http://www.resmed.com/int/products/s9-a ... c=patients )
- Nonin OEM 3012 Xpod kit, 8000AA sensor (Adult Articulated Finger Clip Sensor) with data format 2 for data logging purchased from Nonin. Call 800-356-8874 and ask for Myra in customer service. Be sure you ask for format 2 which allows data logging (transmits 5 bytes, 75 times per second). Here is the order form. Select Xpod, 8000AA, and Data Format 2 on the form. Fax or email the form back to Myra, attention OEM: Fax 763-577-5521 or email [email protected] . She will ask you if it is for commercial or research purposes. I said it was for "research".
( http://www.nonin.com/documents/OEM%20De ... mation.pdf ) for a total of $327 ($300 for the Xpod and sensor, $21 sales tax, and $6 ground shipping).
Here are the specifications for the Nonin Oximeter in PDF format.
( http://www.nonin.com/documents/Xpod%20S ... ations.pdf ).
- Standard 6 foot PS/2 extension cable - $6-10 from Best Buy. The cable has one male and one female connector.
- Other items used included thin solder, soldering iron 35watt, 3-pin computer fan power Y-splitter cable (which I bought at Fry's electronics for use of the Red, Black, and Yellow wires), various heat shrink tubing sizes (3/64", 1/16", 3/32", 3/8"), inexpensive heat gun from Harbor Freight, hemostats, needle nose pliers, metal cookie sheet pan for soldering tray, lighter to burn off plastic insulation, other miscellaneous items.
1: Remove the cover off the ResMed Oximeter Adapter by gently pulling the housing apart. Be sure to take note of how the unit is assembled. I took multiple photographs with my iPhone. Avoid touching the internal chips and circuitry. Gently pull off the tiny plug with the three wires (Red, Black, Green) from the circuit board. There is a small nut the holds the ResMed 3-pin black connector to the plastic housing. ResMed refers to this 3-pin proprietary panel connector as "Adapter Connector". The nut can be removed with a pair of needle nose pliers or a pair of hemostats. As mentioned above, I removed the wire plug from the circuit board and removed the ResMed 3-pin housing connector. I then gently removed the donut from the wire. Do not force the plug through the donut. Take your time. By now, you have a separate 3 wire cable (Red, Black, Yellow wires) with the tiny circuit board plug at one end and the larger 3-pin black ResMed connector at the other end.
2. You can either replace the proprietary 3-pin black ResMed connector with the free end of the PS/2 female portion of the cable (First Method) or keep the ResMed connector intact and solder new contacts along the wire length as described below (Second Method). It is probably easier to perform the First Method. You can also attach a 3 or 4 pin Lemo connector to the 3-wire ResMed cable as casadelane did.
2a. First Method:
Remove the 3-pin ResMed proprietary connector from the small 3 wire cable by melting the solder welds. Use wire crimps or use solder to attach the new female PS/2 cable to the now free end(s) of the 3-wire ResMed Oximetry Adapter cable. I used the PS/2 red, white, and bare wires. I covered the bare wire with black heat shrink tubing for insulation. You can use whatever wires you wish from the PS/2 cable. You just need to be consistent with the other male PS/2 cable. It might be better to use the red, green, and black or bare cables since this will match the relevant cable colors of the Nonin 3012 Oximeter. Cover the solder welds with appropriately sized heat shrink tubing. You can use a lighter or an inexpensive heat gun from Harbor Freight. This method is the easier way to go. You will just need to find a rubber grommet to fit the remaining space between the housing hole and PS/2 cable. You might be able to find the rubber grommet at Lowes hardware section. Alternatively, you can just substitute the ResMed connector with a small 3 or 4-pin connector such as the Lemo connector similar to what casadelane explained in his post. You will likely have to enlarge the ResMed Housing "hole" to accommodate the new connector.
2b. Second Method:
Using cut wire from a 3-pin computer fan power Y-splitter cable and appropriately sized heat shrink tubing, I soldered 3 like colored wires (Red, Black, Yellow wires) approximately 2-3 cm from the end of the ResMed black 3-pin plug. This will allow you to still be able to wrap the ResMed 3-wire cable around the donut on the other end of the cable when you reassemble the unit. I did not cut the original cable wire. I simply burned off a small amount of plastic insulation to access a small amount of bare wire underneath. I then placed a small piece of heat shrink tubing over the new jumper wire and "pulled in" a small amount of the original wire into the shrink tubing for insulation. This takes on a Y shapes configuration. I then drilled a small hole on the left upper side of the ResMed connector (that is if you are facing the front/3-pin connector) to allow access for the female end of the PS/2 extension cable. I drilled the hole just a bit smaller than the cable for a snug fit by hand only. I drilled at this spot taking into account available space that the wires will take up when the unit is reassembled. Insert about a half inch of PS/2 cable into the ResMed Housing. Don't push too much cable in or you won't have the space to reassemble the unit. I then soldered the newly placed "jumper" wires to the ends of the PS/2 wires, which were covered with heat shrink tubing. Be sure to put the heat shrink tubing on before soldering. Also be careful not to prematurely heat the shrink tubing before positioning the tubing over the new solder weld. I made this mistake several times. Also, you can use a short segment of 3/8" heat shrink tubing over the PS/2 cable inside the Oximeter Adapter housing to prevent the cable from being pulled out.
2c. Third Method:
The last method would be to try to recreate a proprietary male connector to attach to the ResMed 3-pin female Black "Adapter Connector". I have not tried this yet. This would involve buying connector pins compatible with the Connector, a plug to hold the pins in place, and a way of securing the male connector to the female ResMed connector. There is a small circumferential groove around the back waist of the ResMed plug in addition to a small bar in the lower 6 o'clock position of the ResMed connector that locks the connectors into place. So far, no one has been able to find a compatible male connector to the proprietary female ResMed adapter connector.
3. Reassemble the ResMed Oximeter Adapter. Be sure to take note of the orientation of the ResMed port connector which plugs into the ResMed S9 machine when you dissemble and reassemble the unit. ResMed refers to this port as the "Module/Adapter port". It has a small notch at one end of the connector to allow it to plug into the ResMed S9 unit in one direction only. I took various photographs with my iPhone to remember how the adapter is assembled. You now have the female end of the PS/2 cable sticking out of the ResMed adapter housing. If you used the second method above, the original ResMed 3-pin black plug in remains intact.
4. Solder the male end of the PS/2 extension cable to the Nonin 3012 cable. Be sure to order this cable without the connector with the wires at the end exposed to make it easier to gain access to the wires. It is very difficult to remove the plastic insulation from the Nonin cable. Be sure not to damage the wires underneath. As mentioned earlier, the wires are documented correctly in the Nonin PDF specification above. I will discuss this below. When you order the Oximeter from Nonin, you have multiple options including a mini-12 connector, USB connector, Lemo 4 pin connector, or without a connector. It would probably be easier to order it without a connector and the wires exposed and ready to solder. Take your time. Be sure to plan placement of you heat shrink tubing over the wires and cables prior to soldering. I placed a long 3/8" heat shrink tubing over the newly joined cables (male PS/2 and Nonin 3012) at the soldering site for wire protection and a professional appearance. This also helps prevent the cables from being pulled apart in case someone trips over the cable.
The correct wire-to-wire connections are as follows:
(-): ResMed Red wire connects to the Nonin Bare/Cable Shield wire.
(+): ResMed Yellow wire connects to the Nonin Red wire.
Serial Output: ResMed Black connects to the Nonin Green wire.
Make sure you keep the PS/2 wires consistent and maintain the connections above.
The Nonin Inputs/Outputs are correct as documented in the PDF file above. The Nonin Red wire is the Power Input, Nonin Cable Shield is Ground/Negative, and the Nonin Green wire is the Serial Output wire. I also confirmed this with a multimeter.
ResMed however uses an unconventional wiring scheme in the Oximeter Adapter. The ResMed Power Input wire is the Yellow wire; Ground/Negative is the Red Wire; and the Serial Output is the Black wire. This is weird, but is works. Just be sure to keep your connections correct. I again confirmed this with a multimeter.
All three wires are needed for operation. All three wires have to be connected for the sensor light to illuminate and the ResMed S9 machine to recognized the Oximeter.
Be sure to put your sensor clip on your finger before starting your therapy or the machine will report the following error, "Check oxi sensor or press dial to accept no oximetry data. This is mentioned in the troubleshooting section of the ResMed Oximeter Adapter manual. You will be able to see the finger sensor red light illuminated once connected to the unit. It will remain illuminated even if the unit is powered off but remains connected to the wall outlet. Also, you will see the live SaO2 and Pulse data in the S9 display while in therapy mode. You can also review overnight O2 saturation readings with the SD card and ResScan software 3.16.
I hope this helps.
Thanks again to casadelane for the original plans. Let me know if you need any photos.
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