So I am very new to this, I have taken a coding class in college so I know a little about that. I apologize in advance for my ignorance.
My project comes from the automotive world. The goal of my project is to take voltage output from an ethanol content sensor, and convert that voltage to a percentage and have it display on a screen.
Im using a Arduino Nano 33 BLE ABX0030 so I can send a blutooth signal to my phone to use an app, but I want a display in the car as well.
To keep things as clean looking I the car I want to use the factory clock display and hopefully repurpose it for my needs. The car is a 2005 Subaru Outback, it has a VFD display that shows the clock on the right side, and the left side displays a few different things that are switched with a mode button. I can see the Current MPG, Average MPG, Outside temperature, Miles till next fill up, and the Elapsed time of my trip. I'm wondering if I can somehow add or repurpose one of these functions to display the ethanol content percentage coming from the sensor.
If anyone has any ideas it will be greatly appreciated. I have a few people on the legacy gt forums who are quite interested in this idea as well. Thanks
Using an existing display, especially in a car made after 2000 would probably be very difficult.
The display will probably be integrated into the cars communication system by the sounds of your description of its many functions.
Your best and safest direction would be a dedicated display.
There are many OLED displays of differing sizes that would probably suit your needs for automobile applications.
I have been trying to figure this out on my own, but I am very stumped on where to go from here.
I have the Arduino Nano 33 BLE (At first I wanted read out through Bluetooth, but I dont care at this point)
I also bought an i2c controller for my LCD screen which is a Sparkfun 16x2 white on black screen.
I have been looking at others codes for what I want to do but they seem to be way more complicated than I think they should be. So I'm hoping someone can guide me to a simple way to take the output of a Flexfuel sensor, and a fuel pressure sensor and display it to a 16x2 LCD. If someone can send me in the right direction of what I need to read, or give me a little guidance it will be greatly appreciated because I'm very lost.
The best advice is the same advice my dear Mother gave me so many years ago. Every problem consists of stuff you already know and stuff you don't yet know. Begin your project with stuff you already know. Please tell us what part of your project you already are familiar with. Get that working, then add a tiny bit at a time.
May I suggest you begin with the display and the electronics that connect that. Quit looking for code and begin to write code to modify something that works. Learn to display various text on the display. Learn to only display when some value changes.
Paul
Samuel082799
Good morning.
i was looking at your post, and wondering if it was possible to go to a u-pull salvage yard, or go on ebay and get another display like the one in your car.
using the second display, you could probe around and see how it works, to see if what you want to do is even possible.
it might also be helpful to get the wiring diagram for your car to see what wires go to that clock display.
my guess is it is going to be some type of multiplexing. you are likely going to have 4 wires going to the display. 2 power and 2 signal.
if you find out that the display is driven by multiplexed data and you figure out what that multiplexed data is, CAN or some other type of serial communications; you could build your controller to intercept that data, filter it to display what you want to keep, then add your ethanol content to that data.
The diagram shows the main instrument cluster ("combination meter") communicating to the VFD unit with a single yellow wire. In the VFD symbol they show a "micro computer" and the yellow input is termed "UART".
You might get lucky and find that the serial is simple NRZ 5V or 3.3V serial stuff as you might see out the serial port of an Arduino. You'd have to scope that line to establish basic parameters. If it's promising, you could then sniff that serial line and reverse engineer the packets sent and figure out how they work: What bytes in the packet are delimiters, data, message integrity (checksum or CRC etc) and any terminating bytes.
You could capture a bunch of serial messages and log what parameters were shown on the VFD for each message.
It's possible that the translation turns out to be completely unfeasible due to encryption or other voodoo going on between the combination meter and the VFD unit microcontrollers. But it might be a simple interface you can decipher...
If so, you might then use your Arduino to intercept that serial stream from the combination unit, substitute the byte(s) that you need to show your info and update any CRC/checksum and send the revised packet out to the VFD unit.
