FB and external devices

[Petrus Vorster]

Hi All

I am member on another group called HackAday where people design all kinds of home projects and small engineering gadgets.
For the big snoring guys on the forum, some may be familiar with the CPAP equipment those people like myself use.

But inside is so few things that one cannot imagine them charging up to $2000 US for the better ones and the one i use (Chinese model) is about $400US.
Down here the price is multiplied by 15 into our terrible currency.

The thought of an Open source USB project came to mind. It is the algorithms and medical research that makes the machines so darn expensive, but inside there is a few pressure gauges and a quiet fan/turbine/blower., that is about it.

Since Freebasic is much more modern than Powerbasic It may be able to help up read data from external sensors and perhaps combine them into a USB connection to a Laptop at first.

Has anyone here ever dealt with external mechanics/servo motors etc, that could give a few pointers how one start to do that?

-regards, -Peter

[Pierre Bellisle]

Hi Petrus,
I like HackAday,

First thing that come to mind is a $5 buck Arduino board with some shields (Add-on board).
Using USB to download some code written with one of the free Arduino compiler.
And then communicate via USB / Serial to get infos.

If you are a HackAday member maybe you already knew all this.

[Petrus Vorster]

Hi Pierre

I will add the Arduino board to the thread on HackADay.
Arduino boards are imports here costing the equivalent of about $100 here.
Will let you know, thanks for the tip.

[Pierre Bellisle]

Go on eBay and do a search for "Arduino" or "Arduino compatible"
Buy Chinese version they are as good as original, sometime better and cost much less.
They work with "Arduino software" witch is now separate from "Arduino hardware".
If you know how to program in FB, you will find it kind of easy to code for Arduino.

$7.14us for a UNO R3 PLUS Sensor I/O Shield Arduino Compatible Atmega328P 16U2 Expansion Board

There are tons of Chinese "Arduino shields" or "Add on" starting at 99 cents us.
Memory board, sensor, converter, USB, Serial, AD converter, WiFi, BlueTooth,
Clock, Relay, InfraRed, PushButton, MethaneSensor, StepperMotor, Terminal adapter, JoyStick, etc...

[Petrus Vorster]

Hi Pierre
Very cool. The guys there seem to agree with this.
Turns out some bloke in Australia created freeware for a CPAP on Linux.
HackADay is very interesting indeed.

[raymw]

I had to look up what cpap is - If it is the small compressor to aid breathing, and you intend making one for your own use, then that is different then making it for others. Not sure why you need usb or other interface. I'd start with an aquarium diaphragm pump, and a simple spring loaded safety valve in the air tube to regulate the pressure (bleeding off excess to atmosphere). Now, you could tart it up with electronic pressure sensors and the like, regulate the compressor speed/whatever, but that is merely more things to go wrong.

[Petrus Vorster]

Hi Ray

The machine functions are quite complicated.
So many guys are using it worldwide and the cost is insane.
It was amazing to see how many guys are tired of paying up thousands of dollars worldwide that many guys would like to see another option.
Perhaps a basis machine with the Airblower and so forth connected to either your Laptop or an Android device.
An Open source device will cost $100 if it can work, compared to up to $2500!!!

The real deal measures oxygen levels, breathing patterns, adapt to sleeping patterns, measured co2 levels etc, etc, air humidity and create reports for sleep-labs and so much more. It also adapts air pressure to and from a person based on this info and is not constant.
And then all this must be done quietly without noise, since everyone is sleeping! (And it does all that by reading the air goming back and forth from a person)
The open source device must be able to do basic sensory readings, measure back and forth Airflow and adapt to sudden air flow changes.

The idea for the blower and internal components were created by opening up some of the machines. (They don't last more than 5 years)

O well, there are other guys over there who had done some work already.
This is a BILLION dollar industry worldwide, anyone who could make a cheap alternative would surely be financially rewarded.

[raymw]

Hi Petrus,
You are concerned with producing an alternative to a commercial product, for 'resale'? I expect there are patents etc. on existing techniques, and as its a medical device it most likely needs to get some type approvals/whatever. The Chinese version has most likely been devised by reverse engineering an existing design, and they are probably not concerned with licensing in various countries. Anyway, pull your Chinese unit apart, write down a list of components, see where you can get them, at what price, find a suitable case, etc., then think of the microprocessor and software and interfacing and then time to build 'em, and I would be surprised if you got much change from the price of the Chinese version.
It will be relatively easy to get the flow detectors, humidity sensors, whatever, but unless they are items from the usual electronic distributors, e.g. RS, Rapid, Farnel, etc., then you will probably have to pay over the odds for individual components from the original manufacturer. The mechanics of the system will most likely stump you, finding a suitable case, lightweight flexible tube of an appropriate size, flap valves, connectors and so on. Once you've got the bits, and decided on what you want to control, the actual microprocessor software will be simple, if you've any experience in programming them. Personally, I would tend to use one of the PIC (microchip family) processors, on a bespoke pcb.

I'm not being negative, but I have an understanding of why some items seem expensive, when you enter the internals, but you have to account for the cost of the original development, and I guess liability insurance, type approvals, advertising, etc, etc. The actual component cost, as you've assessed, is trivial.

I would suggest you try and write a check list of what you need to do, components required, software, pcb, etc., and allocate a ballpark price to each item. First of all, where are you getting the air pump? Will a couple of pc cooling fans create sufficient pressure/air flow? How you going to test? etc. Do you need positive displacement e.g. like the aquarium pump I mentioned? Are there small oil free and quiet vane, screw or piston pumps available. How many days will they last, say 10hr a day continuous, or what is the duty cycle? Maybe some bellows could be designed? How much noise is tolerable, can you quieten it? If in a sound deadening enclosure, will it overheat, be too bulky/heavy/expensive. You're gonna have some headaches, but

Best wishes,

Ray

[Petrus Vorster]

Hi Ray

Luckily i am not the thread leader over there. Its people all over the planet that is participating.
I was curious over the controls, but it seems the Aussie bloke is far ahead of us and has working models already.
still is very interesting how to control all this external equipment.

-regards Peter