Profile: John Taves

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  • 6

I was using the windows version of the UI. There is really no excuse for this delay. It makes the product useless.

I ended up making my own by plugging a cheap rs485 -> usb adapter into my computer and doing a bit of programming. Mine has no delay of course. I have no clue how one could have a 2 second delay when dealing with a 9600 baud data stream.

11 months ago

I managed to make sense of the data going from the VDC to the message center. But to further test, I put my RS-485 reader into the 6 pin connector that the bluefire connects to (with 9 pin adapter) and failed to make sense of the data.

My understanding is that the 6 pin connector should have J1708 RS-485 9600 8N1 and J1587 message format as described in https://cdn.hackaday.io/files/18651797964384/SAE%20J1587%20(2002%20Standard).pdf

Is it going at a different baud or bit format than 9600 8N1?
Your adapter will interpret the higher baud of J1939, but that arrives on different pins, right? So you listen on both, and I assume you set the older pins to be 9600 8N1, but maybe you have to try different baud rates?
Or maybe there is some additional message format for MIDs below 128 that I need to interpret?

1 year ago

Can you elaborate? Is the J1708 different electrically and/or protocol from the VDC/Message bus?

1 year ago

I have an 04 Freightliner. It has a VDC in back that is a receiver on the same serial bus (J1708) that the Bluefire is plugged into. The VDC adds the air pressure data and potentially other bits. It sends that data via a different serial bus (RS-485) to the Message Center (MC) in the dash. The MC adds in fuel level and outputs yet another serial bus to the gauges.

My goal is to eliminate the MC and the other gauges to be replaced with a bluefire dashboard. Is it possible to plug the adapter into the gauge, or MC databus so that I can have the fuel level and air pressure gauges?

Alternatively, if the VDC is not forwarding all the data from the J1708 or the adapter is not compatible with the other serial buses, then can I put an RS-485-USB adapter into the gauge bus and pick off the data I want to add to the bluefire data so I can use the same gauge UI?

I am a software developer, so I can do whatever programming is necessary.

1 year ago

Can you get rid of the stuff that the arrows are pointing to? Double clicking takes you out of the dash, so there is no need for these when in dash mode, right?

1 year ago

I have J1708. The RPM gauge is delayed by a few seconds. It does not seem to pause, so it appears as if the gauge is always 2 seconds behind. (EDIT: All gauges are behind.)

After reading the performance section, I am wondering how this is possible. I don't see "Adapter Data Buffer is Full".

I am a software developer and I don't see any reason for this app to be cpu or graphics intensive. If the adapter is getting RPM data 10-100x per second, then I see no reason for any multi second delay between my foot and the display. BLE should be much faster than the serial J1708 bus, right? Displaying this data is trivial for even a very old computer.

There isn't some goofy algorithm that insists on showing each data value, instead of dropping old values is there? I mean, yes, that's exactly what it seems, unless the J1708 bus has this delay in it.

1 year ago