Building an engine monitor - can it be done?

Just got into Arduino and looking at the possibilities for using it to build something to monitor key parameters under the hood/bonnet of my classic car. My 67 VW beetle is missing a few important dials…there is no temp gauge and no rev counter for one thing…

Some Qs:

  • Is it possible to find sensors to measure the temperature of an engine block?
  • Same question for measuring the frequency/rpm of the engine?
  • Any suggestion for measuring battery health?
  • Will an Arduino survive in the engine bay or will I be forced to run wires through the bulkhead (not keen to modify the car if it’s avoidable)
  • If the Arduino was in a case with a strong magnet holding it to the engine bay would the magnet affect the electronics?
  • Could I use bluetooth LE to connect the Arduino to my phone and show some warnings lights or virtual gauges?
  • Has someone already done this and I can follow their example?!

Thanks in advance for any advice.

yes,
yes,
voltage sensor
yes.
no
yes, need to use google

Classiccarguy:
Just got into Arduino and looking at the possibilities for using it to build something to monitor key parameters under the hood/bonnet of my classic car. My 67 VW beetle is missing a few important dials...there is no temp gauge and no rev counter for one thing....

Some Qs:

  • Is it possible to find sensors to measure the temperature of an engine block?
  • Same question for measuring the frequency/rpm of the engine?
  • Any suggestion for measuring battery health?
  • Will an Arduino survive in the engine bay or will I be forced to run wires through the bulkhead (not keen to modify the car if it's avoidable)
  • If the Arduino was in a case with a strong magnet holding it to the engine bay would the magnet affect the electronics?
  • Could I use bluetooth LE to connect the Arduino to my phone and show some warnings lights or virtual gauges?
  • Has someone already done this and I can follow their example?!

Thanks in advance for any advice.

Yes it is my Friend, my old 1989 Mercedes Benz has LCD dashboard and everything some modern cars do not even have!

And it's called RealDash , some electronic skills are highly recommended though!

Here is the link to your happiness NAPKO

what you ask is very easy and a good beginner project.

any Arduino would work.
I would say to put the Arduino in the cabin and not under the bonnet.

a thermocouple connected to a washer could detect the temperature of the thing the bolt holds the washer to.
there should be easy ways to get oil temperature as well as temperatures at different places.

RPM on a '67 could be RF signals. the radiated noise from the engine can be heard on AM radio's.
but we would typically use either a white dot on the flywheel for a sensor or a non-contact coil over a plug wire the way a timing light picks up pulses.

google about battery monitoring

when googling, use arduino
arduino car battery monitor
arduino car rpm
arduino car temperature

the question becomes what you want to add.
a digital display ?
modify the round dash cluster ?

as for readout. you have lots of options.
many cars have a thin strip of indicators on top of the dash.
blutooth could work
WiFi is easy.
analog gauges are possible.
lots of people have added gages to the dash.

Oil temperature is a bit more common than engine block temperature, there are sensors available that mount in the sump drain plate (with the drain bolt in the center), or that replace the plug on the oil pressure relief valve. Typically a dedicated ground wire is run from the engine along with the sensor wire, chassis ground can be unreliable when making sensitive resistance measurements (which is how the common thermal sensor works).

An oil pressure gauge can be mounted in the same hole as the oil light switch, using a tee adapter (thread size is M10 x 1, not the more common English 1/8-27).

If you have fitted an oil filter, that gives more possibilities.

Cylinder head temperature can be measured using a thermocouple made to mount under a spark plug, If you have newer dual-port cylinder heads, there may be a threaded hole for the temp sensor that was used on the later models.

Engine RPM is usually taken off the distributor wire going from the points to the coil, there are lots of references on building a tachometer showing circuitry to condition the signal properly.

The engine bay is going to be rather hot and is not sealed against the rain, so will be a rather hostile environment. Cabling can be run underneath the car along the edge of the chassis or running boards, look up some discussions of mounting physical gauges to see how the wiring can be run.

Engine bulkheads and bonnets are steel... That's going to block RF signals pretty effectively! Bluetooth is, I'm sure you know, RF.

Loads of great answers here. Thank you all for taking the time! I’m off to research a bit.

Water cooled vehicles can monitor their head temperature reliably as the range is somewhere between 180 and 210 degrees F.
An air cooled vehicle head temperature will vary a much larger amount from highway speed to idle in traffic.
So how will you know what is the correct level?

AS already stated, oil temperature may be a better option for this reason.
Another being those without filters and without regular oil changes can hammer out the main bearings in no time as the crank runs in the casing as a bearing.
With the latter in mind, an oil pressure gauge with a rather large red warning light would be top of my list of requirements.
Gauges always seem a good idea at the time and perhaps as a reference but one cannot beat a large red warning light for noticeability. Wouldn't hurt to flash it while you are at it.

edit - answering OP Q. 7. (Realised reading later, using #7 may have been confused with ans #7! - apologies) Take a look at "Speeduino" and Megasquirt, lots of info, including interfacing with sensors, and also importantly, power supply protection and regulation details. Compatible with realdash and Tuner Studio (a pc/laptop based config and display/dash/logging program), and a few other Android apps that do dash display.

You may or may not use the fuel or ignition control, but auxiliary outputs can also be programmed to act on various input parameters which could (and can) be useful.

A speeduino (your own build customised to suit or purchased) would be a great place to start.

I went deep on my project, 1976 VW Westfalia... Working on full digital dash...

Check GitHub... Found a project on there called ManxGauged. A guy out a digital dash into his Manx.

I'm to early in my project too provide any benefit to you beyond that.... You can see my project here:

I'm currently looking at how to take the injudicious sensor data into my Arduino then transmit to the pi for the GUI. Good luck on your project!

Hello everyone, I am also working on a Realdash project, that is to put it on a 1966 Ford F100.
At first I tested the dash operation on a modern car with OBD2 and everything worked perfectly.
But the F100 has no electronics.
For that reason I started studying the arduino and it is all trial and error for me … I am very lost …
The token lights I got them all working … the sensors on the arduino I was able to get it working. But I can’t get Realdash to recognize the sensors … I know the .xml needs to be modified but I’ve really been stuck here for several days …

That's sad. This thread has no answers for you. Please start a new thread on the topic, and post details of the issues that are holding you back. You will probably need to post the XML and any code that parses it.