On 17 March, 2015 - Thomas Schrein (mailinglists) wrote: > Robert, > > Am 16.03.2015 um 17:35 schrieb Robert Helling: > >Thomas, > > > >>On 16.03.2015, at 14:29, Thomas Schrein (mailinglists) > >><[email protected] <mailto:[email protected]>> wrote: > >> > >>The housing of oDiCo is made from plexiglas version 0.1 and filled with > >>silicon oel. The next housing 0.2 will be milled from POM and the > >>electronic will be an industry factored PCB. Awating to have it in the > >>lake in June ... > > > >once you are in the habit of making housings, you might be interested in a > >project idea that came up here a while ago: We all love to have cylinder > >pressure graphs in our logs. But for the dive computer to records those > >you either need a hose that tends to be in your way or a radio > >transmission which is hard to make reliable. The idea was, during the dive > >to stick with an analogue gauge (as the history is mainly important in the > >log only) but attach a little data recorder with pressure sensor directly > >to the first stage to be read out later together with the dive computer. > > > >I did not really pursue this idea much further since all the pressure > >sensors I could find that fit the specs (up to 400bar with at most a few > >bar resolution an simple readout) almost costed as much as the pressure > >radio transmitters (120-150 Euro/pcs) and, more importantly, my total lack > >of experience in building watertight housings. > > > >You might be at least the solution to part two of the problem. What do you > >think? > > Nice idea, never thought about such a logger. > > Let me first give you an overview about our approach: > We have an 400bar industry sensor in test. We will connect it to our > hardware version 0.1 in the next weeks and go diving. > We made an adapter to connect it to the high pressure hole on the regulator > and connect it with an M12-Sensor wire to the existing odico housing. > http://www.skin-diver.org/skd/export/sites/default/sdiv/bastelecke/odico/odico-entwicklung-2014/IMG_2159.JPG_1997443631.jpg > It works on the land, but we are not sure if its really watertight, that we > will see in the dive. > http://www.skin-diver.org/skd/export/sites/default/sdiv/bastelecke/odico/odico-entwicklung-2014/IMG_2179.JPG_1997443631.jpg > > One option (may be you better say vision ;-) in our project is to use the > odico electronics to control a rebreather using CANBUS (the controller has > it build in already) and therefore the high pressure sensor would act as an > CANBUS node with its own buildin controller, in particular a STMF1x, less > then 5€ each. The electronics could be sealed with casting resin. > For our rebreather approach we accept the existence of wires, so we don't > need to care about energy and communication. The pressure sensors cost about > 80€, plus the adapter for the high pressure, plus the wiring, but that costs > are not a big deal to run a rebreather. > My fellow, Marco, also doesn't care to much building even an self made > pressure sensor with build in electronics . He has a degree as mechanical > engineer and he's really gifted for job! > So we don't care too much to get it water tight. > > From my point of view a logger could be designed like this: > - located at the high pressure hole of the first stage > - length about 5 - 10 cm, cylindrical > - collecting data for pressure + time > - as an option: collection depth+temp > - energy by an AAA or 1/2 AA lithium 3v cell than could be replaced once a > year > - communication via radio (bluetooth, ...) > - shop price < 200 € > > Again, I never thought that would be worth to think about it. I will discuss > with Marco! > If you like we can discuss more. >
I would be interested in such a device, even if they would be built as one off jobs. Only thing i would argue is really important is to make sure they fail in a sane manner, and doesn't leak or dump my gas. Now this one is seriously OT but a idea i hand a couple of mates had as a idea, a depth/time logger with a accelerometer/gyro and try to use that as a mapping device to try to figure out how your movements under water actually where. I talked with another mate who's in the defense industry and they have such devices on there (semi)autonomous rovs, but they combine the accelerometer/gyro with sonar and doppler radar against its surroundings for more input to their odometry models. That would be really cool =) //Anton -- Anton Lundin +46702-161604 _______________________________________________ subsurface mailing list [email protected] http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface
