I'll try to answer all the questions from above:
Mark, I don't know about the Volvo engines. I'm working specifically (at the moment) with DD engines. Those prior to 2006 (DDEC 4 and earlier), spoke a protocol called J1587, on a J1708 data bus. Starting with DDEC 5, the engine DDEC now streams a J1939 protocol along with a J1708/J1587 protocol as well. It is my final intention to work with both. As for Volvo, since it's a Volvo engine, I don't know what kind of diagnostic computer is on-board, and whether or not it speaks J1939. If it does, then there is a good chance this would work.
Terry, I can't work with Silverleaf hardware, I just mentioned it as an existing product that will provides similar functionality.
Russ sent me a private note, that I think is worth mentioning here. He indicated to me that he's got the VMSpc product from Silverleaf, and uses a $10 Ipad app to do this. I've asked for clarification, but I believe this works by a PC plugging into a Silverleaf interface via USB, and then using AirDisplay to stream the PC screen to the iPad for display. Certainly a very workable solution, and a lot cheaper than anything I can do.
Let me describe how the system I'm working with does it's job. I've worked so far with three vendors, but only one has gotten me a working solution at the moment.
This device plugs directly into the diagnostic port on the bus. You connect your iPad/iPhone to the device by selecting it in the wifi settings panel.
My app sends some appropriate information to the device, which initializes it, and data streams from the device. My app, then attempts to decode the information, and the goal is to display it in a really nice way. So, there's no other hardware involved.
There seem to be some much cheaper devices out there that plug into car ODB-2 ports (on board diagnostic ports). Some say they support the newer J1939 protocols, others say they don't, even though they are OEM'ing the same hardware. Personally I'm a little concerned plugging something like that in my bus diagnostic port.
To support buses of the vintage of many of our buses, the device has to support the J1708 physical interface (it's different electrically), and also it has to be able to decode the J1587 protocol. In looking for a device that did both J1587 and J1939, it get's kind of expensive. Wired devices are cheaper, but my goal was to work with an iPad or iPhone, which the only easy way to connect was via wifi.
I did speak with a vendor who quoted me only $125 for an interface that did both, but that required a purchase of 1000 units. I've tried to get a test unit from this company, (they said they would be happy to send one), but I can't get them to return phone calls or email at the moment. Single unit quantities of their device, are in the $600 to $700 market as well.
Anyway, that's the good, bad and ugly of it, at this point. I'm still moving forward, for those who may be interested.
Ray
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