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ODB2 data for Torque on my Android

Fri Mar 16, 2012 1:16 am

I added OBD2 data to my Alltrac for a Bluetooth data feed into Torque on my Android.


Thus far, just the basics, and it needs some calibration. More to come....

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Re: ODB2 data for Torque on my Android

Fri Mar 16, 2012 4:23 am

Haha, been using this at work all the time.

Re: ODB2 data for Torque on my Android

Fri Mar 16, 2012 9:59 am

Have you been using it on a pre '96 car?

Torque normally uses an ELM327 bluetooth device to plug into the ODB2 port.
So, Torque on an engine after '96 is quite simple, just plug in an ELM327 into the ODB2 port and you're there.

However, anything prior to '96 does not have an OBD2 port. I did quite a bit of research and could not find any evidence of anyone else using Torque on a pre '96 vehicle.


Re: ODB2 data for Torque on my Android

Fri Mar 16, 2012 3:15 pm

Yes, 90-95 Honda/acura 3pin data port ;-)

Re: ODB2 data for Torque on my Android

Tue Mar 20, 2012 12:51 am

Tubasteve, The 3 pin Honda port sounds like a ground, Rx, and Tx, does it feed into an ELM327?
How do you get the data from the 3 pin port into Torque?

A while back I made a boost controller with an Arduino (see: http://www.alltrac.net/phpBB2/viewtopic.php?t=32605 )

This project, for the ‘91, is just doing data monitoring (OBDM) and makes it available to Torque over Bluetooth. When Torque connects to a Bluetooth device it first performs some queries with “AT” command request. One of the things Torque ask for, is “What can you (the ECU) tell me?”. I respond, telling it what “Process IDs”, PIDs, I can provide measurement data for. Once initialization completes, Torque starts asking for the PID data measurements which it was told are available.

The Arduino Duemilanove has 6 Analog input pins which can measure a 0-5 volt signal. Thus far, I’m using 3 of them to read the AFM Vane Sweep, the TPS, and the Vacuum/Boost PIM signal. The ECU already uses 0-5 volts for these devices,
so their signals are feed directly into the Arduino analog ports.

The Duemilanove has two digital pins which support interrupts. The fuel injectors are wired “hot” with 12-14 volts. To fire an injector the ECU completes the circuit by taking it’s end to “Ground”. I use a 5.1 volt Zenier diode to limit the voltage and feed that into the two interrupt pins. One is configured

to trigger its interrupt on the rising edge, the other on the falling edge of voltage change.
The interrupt code saves the event times, for injector open time, and increments a counter to calculate the RPMs.

The ODB2 standards and therefore Torque do not have a PID for the “AFM Vane Sweep”
measurement... I’ve provide it to Torque as the MAF value.

Currently, I give Torque the Injector duty time as the “Engine Load”. When I get to it this may be revised to better estimate
engine load.

So, when Torque ask for PID data measurement values I can provide the above. One interesting discovery thus far is that the fuel injectors stop firing when the engine is back loaded. Which means, I loose the RPM measurement.

Also, Torque does not calculate the HP and Torque values. I think this is because it wants to see “Speed” from the ECU and does not use the GPS speed for these calculations.

Version two....

If I redo this with an Arduino Mega, it has 16 Analog pins and 6 digital pins with interrupts.

One of the additional digital pins with an interrupt could will be used to read the RPM signal going to the diagnostics port. This will prevent the RPM dropout when the engine is back loaded. A second pin with an interrupt will be used to read the speed signal to the ECU, with which Torque should then calculate HP and torque.

Some of the other data points I hope to measure with the analog pins are are: the Alternator/battery voltage, engine coolant temperature, the AFMs ambient air temperature, oil pressure, etc.

As in the MPGuino project I should be able to calculate the real time MPG

The Arduino can also remember data values while powered off. I can use this to track the engine run time and mileage for oil changes.


Re: ODB2 data for Torque on my Android

Tue Mar 20, 2012 3:59 am

The Honda data on three pin is very basic, but the connector my dad has concerts #most# to hook upto a special obd2 port. Some early accords data was incorrect along with integras.

I'm a Honda shop, its something i work with everyday.

Re: ODB2 data for Torque on my Android

Tue Mar 20, 2012 6:02 am

Btw, awesome job. Hope itcomes out well :-), too bad you can't read what the computer is thinking, like knock retard and such....you'll get there.

Re: ODB2 data for Torque on my Android

Fri Sep 07, 2012 10:11 am

Holy electrical jargon Batman!! I wish I knew how to do that shit so I could just figure out why my cars bein so retarded...
You guys are truly amazing and give me hope... cuz with smart guys like you around, maybe some day I can be driving my car again... :notworthy:

Re: ODB2 data for Torque on my Android

Wed Jul 29, 2015 1:31 pm

Saw the video on youtube. Is this system still in use?
We planned similar to old Volkswagen, thouh not sure if we have the programming skills needed for Arduino.
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