DIY CPAP machine

[naginalf]

I did a search for this, but didn't find anything. I was wondering if anyone had made or heard of anyone making their own CPAP machine. I know, you're probably thinking that it's a crazy idea. But, it is a rather simple device if you've ever taken one apart. It may be based on pressure, but my machine (yours may be different) is not calibrated to a pressure sensor, the RPM of the blower motor is calibrated to the pressure it creates. Even if one wanted to calibrate pressure, that would be a simple electronic circuit to design.

Anyway, I have two reasons for this. First is that I abhor plastic and the general lack of quality due to it's use. Yes these machines are usually made well enough, but is well enough good enough for you? Mine isn't. Secondly, on a completely different design purpose, and to ask if one already exists, I would like to have a CPAP that doesn't require batteries and that is lightweight and packable such that it would be easy to take camping.

Any thoughts?

[STL Mark]

Guess you could start with the motor on a leaf blower...

[big_dave]

You can find your answer by researching the history of CPAP machines. You can expect your DIY machine to be huge and noisy, just like machines of the 1980's. Also prototypes of any device tend to be fragile. It certainly won't be anything you would take camping.

[archangle]

How do you expect to power your camping CPAP without batteries or electrical power?

[Guest]

If OP starts with a leaf blower motor like STL Mark suggests, it can run on gas. Of course fumes would be a problem.

[naginalf]

LOL, leaf blower, good one. Point taken about noise, just seeing if anyone had done it. I'll look up the history, haven't done that yet thanks, should be an interesting read.

As for the camping cpap (that was two separate points btw), I have a good idea for a camping CPAP without batteries, but I thought I'd just put the idea out there and see what came of it. My own idea I don't want to share because I think it may be good enough to patent. Suffice to say, all you need is sufficient air volume under pressure to last 90mins, then awake and reset it, no electronics are really necessary.

Basically, I'm just seeing if there is any adventurous sorts out there who've done anything like this. Surely there's some serious CPAP geeks out there! No?

[IndyDave]

What about re-engineering an existing machine? Take it apart and re-assemble it in a housing of your choice. I don't know how much waste space is in there, but by using the existing air pump and controller, you keep the noise level down and don't have to re-invent the electronics.

[naginalf]

What about re-engineering an existing machine? Take it apart and re-assemble it in a housing of your choice. I don't know how much waste space is in there, but by using the existing air pump and controller, you keep the noise level down and don't have to re-invent the electronics.

Indeed, that is a thought I had as well. Perhaps I could get a glass expert to simply take a mold of my plastic water housing and make a glass version. Hmm.

[STL Mark]

I think new ideas are how major innovations are made. I encourage you to persue your new invention. Of course sometimes new discoveries turn out to be a bit embarrassing, take this one for example.

[akcpapguy]

You are correct that the pressure sensor is not used to set your PAP machine. However there IS a pressure sensor in your PAP and it DOES regulate the blower speed. This happens when there is a leak in the system which decreases the pressure.

[naginalf]

You are correct that the pressure sensor is not used to set your PAP machine. However there IS a pressure sensor in your PAP and it DOES regulate the blower speed. This happens when there is a leak in the system which decreases the pressure.

I could be wrong, and I don't mean to be contradictive, but I took my machine COMPLETELY apart and there were no electronics on any of the airways or any tubes branching of to the electronics, just filter => tube => blower => water tank and out the back. There were however 4 wires to the DC motor which tells me that it has a very good RPM sensor. On an impeller type blower with a simple airway like this, this setup will control pressure very well. When there is a leak, the RPM pops up, the current needed to keep that RPM goes down, and the electronics adjust accordingly. This also makes it a very good DIY candidate since the electronics are simple. I could hook a pot knob up to the motor and adjust pressure if I wanted.

But that's no matter, I can keep the control, however I would like to be able to have my device controlled by me. Is there some way of unlocking the software with a special smart card or card read/writer?

[naginalf]

How do you expect to power your camping CPAP without batteries or electrical power?

Gravity and possibly some mechanical advantage.

[akcpapguy]

Are you talking about the same PAP machine that is listed in the bottom of your posts?

[archangle]

Are you talking about the same PAP machine that is listed in the bottom of your posts?

He's just making it up as he goes along. He probably doesn't even have a CPAP machine, much less one he actually took it apart.

He'll probably be back later with a different story.

[archangle]

How do you expect to power your camping CPAP without batteries or electrical power?

Gravity and possibly some mechanical advantage.

That sounds like something that would work until you do the actual calculations.

Assume your CPAP uses about 10 watts. 1 hour of usage would be 26,000 foot lbs. If you're thinking of using a weight to power the CPAP, you'd need to carry a 1000 lb weight and lift it 26 feet to power the machine for one hour. Or a 100 lb weight lifted 260 feet.

26,000 foot lbs is an astoundingly high number, but I checked it twice.

Mechanical advantage doesn't help. Conservation of energy still applies no matter what mechanical advantage you have.