Copyright Juha Haapajärvi, Finland 2005


Wellcome to BreatheWise project www-pages.  BreatheWise is Open desing scuba rebreather desing. All information shown in these pages are free to use as long as all delivates are also free and published. 

I have spent thousands of hours with it; I hope that it will be usefull for someone. 




Juha Haapajärvi currently copyrights BreatheWise, but all desing are free to use with only one exception. If you make your own rebreather desing based on this information you have to publish your desing and allow others to use it.





These web-pages are under construction and have preliminary information, everything is subject to change, testing is still on progress, information presented here might be outdated and does not reflect current desing. Most of things are just not documented yet, but maybe after few years….

Don’t risk your life if you don’t know what you are doing. Diving with rebreather need special knowledge and kills. Building one, even more skills are needed.

And remember don’t just copy these; try to understand them before using.




BreatheWise SERIES 4 Feature’s

·        Over shoulder counter lung construction

·        Scrubber: about 3kg

·        Weight:  about 20kg including weights

·        Max depth: theoretical 100m tested 35m

·        Oxygen 2l 

·        Diluent 2l  (300bar)

·        Max dive duration: not known - tested 1h30

·        Easy and fast service, maintenance and setup.

·        No manual mode.

·        Only emergency procedure is to switch to open circuit and bailout.


·        Constant FO2 in low depths to make balancing easier.

·        Automatic switch to constant PO2 mode after max PO2  limit is reach.

·        Fully automated diving – no need to make settings under water. 

·        Any O2/N2/He mix is suitable as diluent

·        On board computer can be used as Open Circuit tri-mix decompression computer.

·        Bhüllman zhl-16c

·        RGBM (folded).

·        3 presettable OC mixes.


·        Price target about 3000Eur





Ø       Manamansalo 2004  (Series 4)


Project Team


Overall owener


Testing and manulas, case

Maybe You ???:

Maybe you could give your contribution.

Just say how and when….



Special thanks to


Tommi S.

Thanks for testing and commenting

Erkki V.  

Thanks for making those hundrets of small parts.

Other Erkki

Thanks for display mechanics proto.


Thanks for finding components and having lots of usefull ideas

Jukka & Tanja

Thanks for encouraging comments


Thanks for commenting some irritating typos in www-pages

YBOD divers

Thanks for giving intelligent arguments.


Thanks for everyone for ideas and instress for my humble project





Document History

09.03.2005 www-bages released.

16.03.2005 Added special thanks

16.03.2005 Added Series 5 preliniminary information

17.03.2005 Added picture of backplate

17.03.2005 Added dymmy software algorithms page

17.03.2005 Added project schedule

07.04.2005 Fixed some typos

14.04.2005 Added picture of Scrubber unit SW architecture