Building a touring/4x4 vehicle data logger — what would be the best da
Submitted: Sunday, Feb 15, 2026 at 16:56
ThreadID: 152181
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Replies:2
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HairyLocal694
G’day legends,
I’m building a small standalone trip/vehicle data logger for remote touring and 4x4 trips for my family and friends and I’m trying to figure out what people actually care about.
Idea is:
Logs engine/vehicle data while you’re driving. (ODBII/K-Line)
GPS coordinates.
Analog inputs for battery voltages or digital inputs for switching signals.
Saves everything locally to SD card.
Can review trips later.
Potential live dashboard via WiFi on your phone.
Viewing historic data will be from CSV or similar where graphs can be setup..
Question for you guys:
When you’re out touring, what do you actually monitor? Temps? Voltage? Fuel usage? Nothing?
And have you ever had a failure or breakdown where you wish you had data from before it happened? Like if you knew your battery has been struggling to charge over time before you went on a trip and had a starter motor failure etc, this could have been flagged earlier for replacement.
Reply By: Member - Warren H - Sunday, Feb 15, 2026 at 18:50
Sunday, Feb 15, 2026 at 18:50
Everything you've listed can be done using an OBD2 reader and the Torque Pro app or Apple equivalent. Wrt parameters, coolant and transmission temps for on-the-go visuals, then other parameters such as intake air temperature, rail pressure for problems but proper interpretation of these is level above my expertise.
AnswerID:
648957
Follow Up By: HairyLocal694 - Sunday, Feb 15, 2026 at 18:58
Sunday, Feb 15, 2026 at 18:58
Thanks for your input. I do agree about the Torque Pro app and have recently come across it but never used it. From what i can see is it can only log ODBII data and not read or process external inputs.
I will have to try Torque Pro for a bit to see what it has to offer.
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Follow Up By: Member - Warren H - Sunday, Feb 15, 2026 at 21:19
Sunday, Feb 15, 2026 at 21:19
You are correct it only deals with OBD2 data.
FollowupID:
930591
Reply By: RMD - Sunday, Feb 15, 2026 at 20:57
Sunday, Feb 15, 2026 at 20:57
Hairy.
If you monitor the voltage and it is insufficient, then WHAT!
How would a monitor be able to show a BATTERY struggling to charge? If volts and amp supply is sufficient, it will charge, and you still won't know if it has the capacity to start the engine later. SO what does struggling to charge mean?
With the starter motor failure, no meter will tell you that! How could you predict the burning of contacts to stop the starter operating??? or a MECHANICAL STARTER FAILURE???
I use the fuel gauge to see the usage and conditions vary that too!
I made a system to indicate if head temp got too hot, ie, sounds an ALARM. It is the best way!
Apart from voltage, maybe, and
water temp, you have no control over most of it anyway so not much use storing the data. WHO is going to interpret it later? And what are you going to do about it?
AnswerID:
648959
Follow Up By: HairyLocal694 - Sunday, Feb 15, 2026 at 21:23
Sunday, Feb 15, 2026 at 21:23
1. A weak/older battery will have more voltage sag when cranking and bounce back to nominal voltage slower. This is measurable just by volts alone.
2. A bad starter can be seen as a weak battery if just looking at the collected data. If ODBII data was recording cranking RPM, maybe it can be monitored over time to show if starter is struggling. (Filtering out temp variations etc would be essential). Now i don't think a mechanical failure can be predicted but there can definitely be data pointing to worn out hardware.
3. I would want to monitor the health of my batteries(Main and Aux etc) and other parameters also that can point towards worn engine hardware.
Just hypothetical but can be implemented with the right data collection and testing to prove what data corresponds to what physical problems.
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930592