Open-source USB CPAP machine

Breathe free, night and day.

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Obstructive sleep apnea is a medical sleep disturbance where the patient's airway collapses during sleep, preventing breathing. When blood oxygen levels drop the autonomous part of the brain then awakes the patient enough to resume semiconscious breathing. The patient never wakes enough to become aware of it, but sleep is disturbed, and the patient never enters the crucial deep sleep phases

Continuous Positive Airway Pressure is a conceptually simple solution which splints open the airway using pressurized air, but the devices are all very expensive, therefore treatment of sleep apnea is limited to the rich.

I believe that it is possible to build a simple CPAP machine that is controlled by an external device via USB

Team members can decide which part they want to work on:

  1. A blower to produce pressurized air. The pressure is low, only a few centimetres of water, but it needs to be super quiet, because the patient will be sleeping while the blower is running.
  2. A flow monitor. It is necessary to monitor and record flow, to ensure that the patient is being effectively treated by the device.
  3. A pressure control loop.
  4. A tube from the blower to ...
  5. ... a face mask of some sort, to introduce the pressurized air into the airway.

  • Just starting:

    indigoredster4 days ago 0 comments

    reminder.... "Remind me to take a photograph of it and post it here. "

    I just go approved for medical on my cpap, so now I can compare the DIY I 'm making w/ the one I will get fitted with.  

    I ordered a mask:

    and (erroneously) a fan that barely meets the specs just to evaluate:

    Brushless Radial Blower - UTUO DUAL Ball Bearing High Speed 12V DC Centrifugal Fan with XH-2.5 Plug 120mm by 120mm by 32mm (4.72x4.72x1.26 inch)

    From Wikipedia: The pressure required by most patients with sleep apnea ranges between 6 and 14 cmH2O. A typical CPAP machine can deliver pressures between 4 and 20 cmH2O. More specialised units can deliver pressures up to 25 or 30 cmH2O. CPAP treatment can be highly effective in treatment of obstructive sleep apnea.

    The motor 

    • Max. Air Flow: 42.45CFM
    • Max. Static Pressure: 41.10mm-H2O ( oops I though it was in cm-h20 )

    The real cpap motors look to be similar to RC motors and ESC's. Should be easily 3d printed:


  • Replacement harness.

    Niel Malan09/19/2017 at 09:16 0 comments

    The Resmed Mirage Quattro  full-face mask I use is a wonderful  design. It fits snugly and it's quiet. 

    It does wear, however, and the part that wears out fastest is the harness. The harness is a nice one-piece design cut out of a neoprene and fleece laminate, with velcro-adjustable straps. 

    The hooks of the velcro wears out the loops of the fleece, so that after a time the velcro no longer works. I've successful sewn velcro loop material to the harness, but eventually the neoprene collapsed too. 

    After some experimentation I was able to devise a replacement harness out of haberdashery elastic, mylar sheet and a stapler. It is custom-made for me without any adjustability, so any practical implementation will need a measurement scheme. 

    Remind me to take a photograph of it and post it here. 

  • Project Started

    Niel Malan03/11/2015 at 08:20 0 comments

    At this point the project is a wish more than a project, but if I put it out there perhaps we can get people to join and create hope for lots of people.

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battletux wrote 05/12/2016 at 20:43 point

Points 4 and 5 could be negated initially, as you could use commercial products to start with. They are not cheap (£100ish) but they are at least a quarter of the price of a CPAP and fifth of the cost of an APAP.

Once the CPAP design is done then you could look to designing a cheaper mask or nasal pillows.

  Are you sure? yes | no

Niel Malan wrote 05/13/2016 at 11:34 point

I agree. Tube and mask are not priorities, but if someone wants to start work on that, it could one day start saving patients money. The masks wear out, and an affordable replacement would help. 

  Are you sure? yes | no

battletux wrote 05/13/2016 at 18:53 point

the tubes can be bought cheaply on eBay. A mask with a replaceable seal like the resmed quattro fx would be an idea to keep cost of consumables down.

  Are you sure? yes | no

Niel Malan wrote 05/13/2016 at 21:43 point

Can't buy on eBay in Africa :-(

  Are you sure? yes | no

Stuart Longland wrote 05/13/2016 at 21:46 point

Maybe as a cheap alternative, modding a half-face respirator?  They take a cartridge that screws into the front, you could possibly make a fitting that screws into the same place.  Then the mask can be bought at a hardware store.

Edit: Actually, this is pretty simple, I just had a look at a "Protectector Safety" one I had laying around, the cartridge coupling and outlet valves just fit through holes in the mask itself, it'd be very trivial to 3D-print plugs for the two outlets and replace the front cartridge holder with a coupling for a breathing tube.

  Are you sure? yes | no

Niel Malan wrote 05/13/2016 at 22:10 point

Brilliant idea, Stuart!

  Are you sure? yes | no

Niel Malan wrote 07/30/2015 at 14:04 point

Here's an article that shows what a CPAP machine looks like on the inside.

Our's doesn't have to look like that.

  Are you sure? yes | no wrote 07/29/2015 at 11:12 point

Can anyone volunteer and give sketches for how a Cpap machine works? I can provide 3D models that are 3D printable or laser cut. CPAP machines are quite expensive and itnwould go a long way to make one inexpensively.

  Are you sure? yes | no

Niel Malan wrote 07/30/2015 at 10:05 point

I've added a block diagram to the details above. 

  Are you sure? yes | no

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