I just got a call from Oceanic and it looks like the only thing missing that I really want is the average depth, which I should be able to calculate manually or with some other spreadsheet program. I also downloaded the appropriate version of the OceanLog software to have a look at it. Not bad.
downloading to PC
- Thread starter fjpatrum
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In this case, building this kind of stuff is what I do for a living and projects like this are fun for me to "reverse engineer" so I don't consider my time as a cost. I should, but I don't. If I did it would certainly be cheaper to buy the proprietary part.
FWADIVER
Contributor
there is more to it than just the cable, it is a usb to some sort of serial interface (CAN, I2C, SPI BI,etc couldnt tell you for sure) can you reverse engineer it? Yes, but probably not without buying a cable first and doing some bus pirate work. Its easier to just buy the cable.
It's not that difficult to reverse engineer a 6 pin (max since it's USB) serial interface with or without the cable, assuming I can put the computer in "PC mode" (or whatever mode is used for downloading data from it) without having a cable attached. That's a big assumption, though. A quick check with an o-scope with some serial logic analysis capabilities will do the hard work in a matter of minutes, if that long.
The drivers that Oceanic uses are available on their website for free download as well...
Like I said, I can do it for ridiculously cheap, if I want to bother. Or I'll wait a bit and spend the money on a cable.
FWADIVER
Contributor
You are assuming you can get your solution to talk to the USB drivers they are using. Its not as trivial as you make it sound. You are assuming the data stream looks like something normal and isin't some other bit banged nonsense they did on the cheap. I have a strong suspicion that most of the 3 pin ones are using a FTDI chip so maybe that will point you in the right direction, but getting over the driver hurdle will still be a royal PITA, but then again i'm not a software guy. Also the computer waits for a handshake before initiating download, so sitting there looking at it on the scope is going to be useless unless you know the handshake to initiate download.
RonR
Contributor
True words...
The cable is the easy part, and unless there is necessary circuitry involved in the adapter then making one yourself should not be a problem at all. The driver is another issue. However most manufacturers offer their software as a free download. If you can hack together a cable, why not try it with their software?
If you are wanting to write you own dive log app, you might check Jef Driesen's
libdivecomputer, a library for communication with various dive computers.
An open source library for communications with various computers, including Oceanic.
The reason that manufacturers don't just use standard cables is that the standard plug-in parts are neither waterproof or able to withstand the environment. Standard connectors would have to be placed behind a waterproof door that would need to be removed to connect, which when opened would expose electronics, and which might not always get perfectly closed by the end user
. Additionally, those exposed pins can be used to sense the presence of water and turn on the computer. So most end up with either an adapter or some kind of custom cable. Eric above describes accurately the economics of making and distributing a custom fitting in small volume. Other options include IR (which still requires an adapter and drivers, and is much less common than USB), and wireless technologies (Bluetooth or others). On the Cobalt we went with USB and an adapter, because we needed some exposed pins anyway to charge the battery and sense water, the cost of adding a few more pins was negligible and USB is, well, pretty much universal. All our adapter does is to connect the USB pins on the Cobalt to a standard cable. So long as you can figure out which pin goes where on the Oceanic the hardware part is easy.
fire_diver
Contributor
Not all the cables are straight cables. Some of them have a chip built into the mount that allows the interface.
The companies that make the computers should supply a cable with it in the first place
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