View Full Version : Propeller Digital Dash?
11-17-2010, 03:47 PM
I have done work with Arduino and Picaxe in the past and would like to step up to Parallax. I was wondering with the integration of video, would it be possible take readings from the RPM sender, Vehicle speed sensor, Gas level, battery, water temp oil temp etc. and make a program to display the info on a lcd screen? Using the propeller?
11-17-2010, 04:30 PM
I sure think so. The video capabilities are up to the task. You've lots of options, with the RAM being the deciding factor on how it all goes. The task you want to start can be broken into little, modular bits, built up a layer at a time.
You could start with a basic dash, add a indicator or two, then build out the sensor portion. Once that works, it's just a matter of building out the other sensors, feeding data to what you've already got written video wise.
It's a very good project for Propeller, and how it works with blocks of code from the Object Exchange. Many of the things you want are already written, leaving you do connect them together, and supply some data.
11-17-2010, 07:09 PM
The propeller should work. The BIG headache is going to be interfacing with the vehicle.
Using the vehicle's OBD2 port would be the way to get all the vehicle data you could ever want. Another problem to watch out for, the are now different OB2 protocols.
The following link does a fairly good job of describing the differences.
11-17-2010, 08:37 PM
Actually, I did this a while back for a custom Ford Excursion that we built for an episode of Pimp My Ride.
It tied into the OBD-II port for a lot of the data and directly into a "sensor interface" module for the rest. (It was a bunch of ADCs in the interface module.)
11-18-2010, 12:11 AM
OBD1 & OBD2 interface chips
I'd think a prop could do the same thing.
Bob Lawrence (VE1RLL)
11-18-2010, 12:57 AM
Try this old thread:
11-18-2010, 07:39 PM
This is a project I've worked on since leaving the BS2 behind. Right now I read the 0-12 square wave tach signal. Put it through an opto, then have an object from OBEX give me the frequency that I convert to RPM. I display RPM and MPH on two 4x7 LED displays. I think adapting it to a serial LCD may be actually easier than writing the MC14489 chip drivers that JonnyMac helped me with. The VSS signal is taken from a wire in my Toyota that I have the aftermarket cruise control hooked up to. It is a 3.3 volt square wave. I was running it through an opto too but the current draw of the opto was causing me to get a warning light on the dash indicating a power steering failure. Next I'm going to put 10K between the Yaris VSS and a Prop pin and try it again. I also have an outdoor temperature sensor for the third LED display but I haven't found the time to integrate that yet. Objects for the sensor exist that display to VGA. I just have to dumb-it-down to a compact, bright LED display. I also designed an analog display with 33 lites but still have to finish the software for a 32-channel controller chip.
11-19-2010, 02:23 AM
I've been working on a very similar project for my '07 4runner. I'm using an ELM327 as the interface to the ODB-II and using a propeller to parse and display the data on my Kenwood head unit. The head unit has a composite video input and the propeller drives it nicely. The 4runner uses the CAN protocol and the ELM327 handles all of the CAN messaging. I have the propeller send requests to the ELM and the ELM queries the CAN bus. I've attached a photo of the display in the truck.