Hi all, just getting started with real dash and as many here would like to design an instrument cluster replacement (if possible). I have a '99 Isuzu which has the usual spedo, rpm, coolant, fuel gauges plus 18 indicator lamps plus 6 4wd status leds.
I have started with simple hardware testing using a pi with android as well as windows10 and an arduino mega 2560 using the raw templates from the github page. Everything connected as expected, although I can see a perceivable delay in the trigger of a digital input signal, for example simulating a turn signal, if I contact the arduino pins the indicator comes on, but on release it remains on for some amount of time.
So if I were to connect that to the cars turn signal indicator it would show constant rather than blink, is that typical for this simulated can bus?
Would the actual can bus have the same type of delay? before I start hacking in to that, which given the model year i’m not sure that info is even on the can bus although Isuzu was in collaboration with GM so maybe GM standards apply?
Should have included that Arduino is connected via usb, tested on both windows and android with the delay.
Typically connecting to CAN is plenty fast of getting values in real time. The bottleneck is how you transmit the CAN data from your device to RealDash. Using 9600 baud serial connection will definitely cause some delay, but anything above should work just fine.
Also note, that some microcontrollers (Like some Arduino nano) are not fast enough to read 1Mbps CAN lines and will start skipping frames. At worst, this may cause one specific frame to be skipped all the time and it appears like RealDash never receives that particular frame.
Thank you for the reply,
The Mega 2560 and Realdash are both set to the default 115200 using the unaltered files from GitHub. Any thoughts what I can try? Can i safely comment out the analog stuff from the Arduino file without messing up the can message?
Okay, I have tried it on 3 different systems now and all have the same 2 second (approx) delay from time of release of trigger to the indicator light going out. I have tried Windows 10, Pi3 with lineage Android, and an Android head unit. Is this normal?
It is 115200 baud rate not 9600
You will not have very much useful data on the can bus for your car. You will need to bring all of the signals into the ardunio and build your own can bus packets. That is what I am doing on my project. I am using an arduino mega 2650 with no delays. It is about making sure you ardunio code is efficient and the communications are setup correctly.
Thank you for the post!
I did figure out after looking at a bunch of wiring diagrams there is no central “can bus” just serial lines between the different modules to the PCM. I am now planning to bring all the indicators to the Mega 2560 through level shifters. The odd thing with the delay is it is only the digital inputs, analogs seem to be fine.
I am kind of feeling stupid cause I am stumped with the ino file getting more than 16 digital inputs using variables like in the example file, I will just keep hacking away and get it eventually! worst case just type line by line …
Solved issue with the digital input delay using the example sketches, you have to change to input_pullup with either the internal or using external resistors and changing the comparative statement to LOW, now it’s just about instant status change. Hope it saves someone else a few hours!