Am 19.03.2015 um 14:14 schrieb Anton Lundin: > 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.
It seems there's at least some interest in such a device but to get a retail price below 200 € one needs to produce/sell more then a couple... I also doubt a kickstarter project will help here :( Maybe the only option would be to design such a device in the public... I have some contacts to a pressure sensor company and a university, maybe that's a nice student project... > 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 =) Personally I doubt you get the needed accuracy by only using the accelerometer and gyro... but you could also couple it with some buoys which sends a ultrasonic beacon on which you can triangulate (like gps) /martin _______________________________________________ subsurface mailing list [email protected] http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface
