Ive been a member on this forum for a while now, but i never had anything to contribute until now. I am big into computers and just recently i started messing around with the can bus in the rx8, i am slowly mapping all of the id's and other data out and ive found that i can alter the data on the dash!

Using this i could possibly change the useless temp "idiot gauge" into a real one, and maybe make that useless oil pressure gauge into something useful (although I'm not sure what yet)

The point is that if i continue to work on this i could just make it something that i could plug into the obd port and be able to change everything on the dash to what someone wants (the radio screen is a possibility but i haven't even touched that yet).

I was just if anyone has ever tried anything like this before?
And if not might there be a market for something like this?

 

Umm... it's kinda been done. Search for "GOODbox" and "RxDuino"

 

The GOODbox only controls the LCD information display, not any of the gauges on the dash, and the RxDuino is for S2 RX-8's only, so you can't truly say "it's been done".

However, to be honest, even if you could convert the oil pressure 'gauge' into a real gauge (assuming it's actually a proper stepper motor gauge and not something that's only capable of moving to one of two positions) it doesn't show you units, so I'm not sure how useful that'd really be.

Also, as far as I know, you can't control the LCD from the CAN bus (like you can on S2), because it's controlled directly by the audio head unit. This is why the GOODbox physically has to tap the LCD's control wiring to override the head unit's commands.

 

you are big into computers yet you obviously did not search, I see big blue screen of fail ...

 

i never saw the RxDuino, but i don't search the s2 forums. while its interesting, they changed alot in 2009 and not only are the CAN protocols a little different, the ids of everything have completely changed. and I have seen the GOODbox before, but i don't really want to do much with the radio display, however some of the info for it is on the slower 'ms' canbus that goes to the obd port, along with most of the other non-critical controls and sensors, while what im mostly interested in is the 'hs' canbus that controls the dash and most important information.

as for the dash, the oil pressure gauge is a full stepper motor, unfortunately it's maximum setting is at the 'normal' position a little past vertical. so that's a little annoying, but ill find out some use for it.

i finally got the temperature setting working but i have run into another problem... the entire dash only has one address and is updated with one command, with different parts of the command that is sent to it controlling each instrument. so if i want to change anything there, i need to recreate the ENTIRE signal for everything going to the dash, from coolant to fuel level to rpm and speed. not only that, but by sending commands to the dash, i need to kind of 'tell' the ECU to stop sending those messages so that they wont interfere with mine. while all of this is possible (and im definitely going to do it) im not sure i would want to make anything to sell, because now im getting into the territory where if my device screws up, the entire dash stops working...

 

The S1 RX-8 only has a single HS CAN bus.

That sucks about the oil pressure gauge. One would have to modify the hardware to get full range of motion.

I suppose it makes sense regarding the dash 'unpacking' a single command to split up into all the different instrument readings, as after all the dash is a single CAN bus module. Things would be a lot more complicated if each instrument were a separate module with its own bus address.

Just out of interest, is there any way of controlling the trip meter display, or is that all self-contained within the instrument cluster?

 

as far as i can tell, both the odometer and the trip settings are received from the speed portion of the command, so they cant be modified at all (although i could be wrong because there are still 2 bits that are in that command that i have no freakin idea what they do). and fuel seems to be controlled by something else, probably analog.

also, i just noticed that there is another signal coming FROM the dash that i haven't seen until now, and when i stop the messages going to it, it also stops the ones coming from it... so who knows what kind of important **** I've been interrupting

 

Well from what I know one of the problems is that the oil pressure sender unit on the s1 is that it's basically an off on switch. Anything above .35bar puts the needle to the normal position on the gauge. I've been contemplating what would happen if I use the rx7 fd(great pressure gauge, but the sensor does mess up) oil pressure sender unit on there, it has the same thread

 

This is pretty awesome, learning how the data flows through the ECU & the different modules in the car.

What are you using to "read" the datastream?

 

the problem is both with the oil pressure 'switch' sensor, and the dash which only goes up to a little past vertical. my first idea for the oil pressure gauge was to make it an AFR readout, with stoich being vertical, but seeing as it doesn't go much past vertical at most, that would be annoying to look at, i guess ill just leave it at what it is.

my first attempt at doing this was with an OBD II Bluetooth module i got on ebay to work with the Torque app on my phone, but i really quickly found out that it overwhelms the transfer rate trying to sniff in on all of this stuff. so i went out and got an ELM327 chip online and connected it to an old RS232 to USB adapter i had laying around. as of right now I'm using a sloppy java program to read and write the data.

 

Fyi the s1 radio display resides on an SPI bus, not can. Second, I would think long and hard about modifying data that gets sent to the instrument cluster on an actively operating vehicle.

 

Don't worry, I'm definitely not driving out until i am confident i know what the hell I'm doing, and thanks for the tip about the spi, that could help with some other stuff, are the hvac controls also on that, or are they just hardwired?

 

The controls are hardwired. Btw, I would get a used cluster if you plan on mucking with it. Accidentally reset that odometer and you are going to find yourself signing some federal documents

 

im like 99 percent sure that you cant reset the odo. without opening it up and really messing with the internals. the way it determines the mileage is from the speed data that is sent to it.