Proprietary ResMed A10 Power Connector Electrical Details

[Snoopy.pa30]

Hello Apnears,

I am about to head out with my Scout Troop for a camping weekend, and don't want to be without my ResMed AirSense 10 Autoset.

Other leaders complain about the snoring, and I agree many of them snore very loudly.  I on the other hand don't hear myself, but am told I snore LOUD and PROUD.

Anyway, as a bit of a geek, I would prefer to build my own.  From my searching so far, I have not been able to locate electronic specs on the Connector.

I have found the physical specs on the connector in this thread:  http://www.apneaboard.com/forums/Thread-...#pid164001

Really hoping someone has checked it out and can let me know.  If I can find the connectors up here in the Great White North (Canada), Big Smoke (Toronto) area, I will do some probing.  It would just be a bit nicer to know what probably resistor size I would need and pick up all the pieces at once from my (sort of) local electronics shop.

Thanks in advance!
Snoopy

[archangle]

On the S9, I think the connector is proprietary. It also requires 24V.  There appears to be some signals other than voltage on the connector that the machine will refuse to function without.   It's effectively "copy protection" that locks you into buying power supplies from ResMed. I vaguely recall one board member probing the pins and finding out there were some serial digital signals on the pins, not just voltage levels.

I don't know if the A10 machines are the same, but I'd be surprised if ResMed would release their grip on the replacement power supply market. It does appear that the A10 uses 24V.

There is an overpriced ResMed DC-to-DC converter that lets you run your A10 machine off of 12V DC. 

ResMed doesn't seem to indicate whether or not it's safe to use an inverter to power your A10 machine, or whether it needs to be pure sine wave or MSW.

[Snoopy.pa30]

Thanks Archangle,

Unfortunately being up in Canada, my local suppliers price is about $200 Cdn (yah, only about $10US..   ok maybe $150 US) for the ResMed 12v Power pack.

As I have a "reasonable (but probably dangerous   ) " understanding of electronics, I can probably build my own for about $40 Cdn (for 24v supply and about $60 for 12v supply), if I can get the last few details.

From what I have learned so far (but not verified) the A10 uses 24V DC on a 1mm Diameter Center Pin barrel connector.  That will be my first challenge - to see if I can find the connector.

The rest should be "pure" electrical engineering for the circuit.

I will have to search for the idea of serial digital signals on the pins and not just voltage.  That is new information for me.  Not impossible, but I don't see any "reason" or logic for it.  Other than perhaps forcing people to buy their product....

Thanks again for the feedback.

Snoopy

[archangle]

I will have to search for the idea of serial digital signals on the pins and not just voltage.  That is new information for me.  Not impossible, but I don't see any "reason" or logic for it.  Other than perhaps forcing people to buy their product....

The "legitimate" reason for the digital signal would be for the power supply to indicate whether it's the high power version of the power supply that will run the humidifier and heated hose or the low power version that won't.   Or to let the power supply verify it's working properly before the CPAP machine starts.  Or to prevent someone from "accidentally" plugging in the wrong power supply.

I have little doubt that a large part of the reason is to protect profit margins. 

It was an anonymous guy on the internet who said he found the digital signals, so it's got to be true.

[Snoopy.pa30]

The "legitimate" reason for the digital signal would be for the power supply to indicate whether it's the high power version of the power supply that will run the humidifier and heated hose or the low power version that won't.   Or to let the power supply verify it's working properly before the CPAP machine starts.  Or to prevent someone from "accidentally" plugging in the wrong power supply.

I have little doubt that a large part of the reason is to protect profit margins. 

Very True. 

It was an anonymous guy on the internet who said he found the digital signals, so it's got to be true.

   Thanks, you made my morning!!!

[foss]

Resmed's DC to DC converter is well worth the cost. It is very efficient and wastes little energy in the conversion. I have a technical background and intended to build my own converter. I started the project but then learned through actual measurements that Resmed's brick was quite good.

Prior to obtaining the Resmed converter, I used a good quality inverter. Inverter's are typically very inefficient and convert a lot of energy into heat, hence they almost all have built in fans.

Consider purchasing Resmed's converter. I found mine at a good price on one of the online suppliers.

v/r
Jeff

[Snoopy.pa30]

Thanks Foss,

I have borrowed a buddy's inverter and will see how long my batteries last in my at home testing........

Being in Canada, my local supplier cost for the ResMed Convertor is excessive, and online suppliers have to add shipping and duties, so cost gets a bit up there.    

Now looking to source the connector (barrel plug connector) - if you have any suggestions I would appreciate them (already visited my local shop and doing online search thru digikey and several other retailers.. No Joy).

Any suggestions or links would be appreciated.

Thanks

Snoopy

[Snoopy.pa30]

Anyone reading this far... 

I found, on this GREAT site  , a long discussion on creating a Battery Backup that also discussed the ResMed A10 Battery Power circuit.

This is for the technology geeks and hackers that want to build their own (like me), either to save money, or because you can.

http://www.apneaboard.com/forums/Thread-...ht=battery

This is a LONG thread, and on page 18 is a circuit.

My issue is finding the Physical Connector now.  My local retailers don't have it, since it is much bigger than normal.  Some power supply packs have a 2 connector plug, not the 3 that we need for the A10...  

Might have to resort to chopping the wires off my official power supply and make adapters for each to match.

Hope this helps any other techno hackers out there.

If any of you know of a supplier for the connector, pleas let me/us  know.



Thanks.

Snoopy

[yrnkrn]

I had ordered a suitable cable from AliExpress. Open the site and search for "7.4x5.0mm Plug" there are several sellers.

[Snoopy.pa30]

Thanks yrnkrn,

My measurements on the A10 connector are more like 10mm x 5mm, so not sure if I am measuring correctly.  I hope the one you get works.

I also have a newer immediate time limit (this weekend for family camping), so I think I am forced to do the CUT and SPLICE method.

By that  I mean:

Cut off cable from current (official) power supply.
Make a double set of connectors:
     Make a +24vdc and GND connector (probably BNC type)
     Make a Signal (3.3vdc) and GND connector (probably BNC but opposite orientation)

Then make the Battery Circuit and make double connectors - same orientation and type as above.

Just my current plan... not a recommendation of suggestion for others.

Do at your own risk..

Snoopy