Multi-function engine monitor gauge

[thebuildist]

Thanks David, that's pure gold. So you'd set the "OK" range on hydro oil to something like "yellow at 200, red at 250"? And when you're really using the machine, the needle should sit high up in the green range, near but not on "yellow"? That seems reasonable to me.

For RPM, Google found some folks over at a Wheel Horse site who say that on an Onan twin that one of the leads coming out of the voltage regulator can be hooked straight to a tachometer. So first thing I'll do is try it with the tachometer I've ordered, and if I can get any consistent movement at all, then I can use that lead.

If that doesn't pan out, I'll revert to coiling a wire around the spark plug wire. It's apparently a time-tested approach. But because that coiled wire is apparently subject to picking up a lot of interference/stray signals, it would mean having to build a little more extensive circuit to buffer before I hook it up to the Arduino. So the voltage regulator path is a little cleaner and easier.

Bob

[DavidBarkey]

So you'd set the "OK" range on hydro oil to something like "yellow at 200, red at 250"? And when you're really using the machine, the needle should sit high up in the green range, near but not on "yellow"? That seems reasonable to me.
Quote
@thebuildist Ya Bob that right on the money in books .

[thebuildist]

Where at in the system did you place your temperature probe? Sitting in the reservoir? Right before or after the oil cooler?

Bob

[propane1]

So did a little grass cutting with the Case 224 and watched the gadget, just for fun. Cleaned oil cooler before starting to cut grass. Oil temperature was 63F before I started the engine and was 120F just as I stopped cutting the grass. Outside temperature was 69F or 21C. Rpm was set at 2700 while cutting grass. Time went from 0.3 hours to 1.0 hours. On my tractor the temperature sensor is mounted on the pipe before the cooler. I would say that if it was 85F here today the oil would of got up to 140F or so. Is my guess.


Noel

[DavidBarkey]

Where at in the system did you place your temperature probe? Sitting in the reservoir? Right before or after the oil cooler?

Bob

Mine is at the filter housing as there was a npt. tap already there . Filter is inline between the 2 coolers . So it is both before and after .

[thebuildist]

Well, stage 1 is a success.

It only took a few minutes of fiddling to get the tach to be controlled by the Arduino.

https://youtu.be/KQ9CtKHzyOs

Next I'll work on writing the program that will output the data to the gauge. I'll start with static/pretend data and get it where it can cycle through and such.

When the RGB LED's get here I'll tear apart the tach and see what it's going to take to embed the LED's in its face, and work out the code and circuit to light up those LED's for each data type.

More to be done after that, but it's enough of a plan for now.

Bob

[Eugen]

@thebuildist maybe I haven't been paying attention as I should have, but now I'm confused. I thought you're going to use a digital display round dial which would just cycle through the various data displayed. But in the latest message you mention actual LEDs on the tach. Or maybe you will have a real tach + LEDs and for the other data (temps, electrical) use the display?

Or maybe you're using this analog tach to display all the data? In that case you are planning to move the "hand" of the analog tach using the arduino, and the LED's are simply a visual aid in quickly establishing normal range on the particular data type? Or are the LEDs telling you which data type is being shown at any point in time?

[thebuildist]

Or maybe you're using this analog tach to display all the data? In that case you are planning to move the "hand" of the analog tach using the arduino, and the LED's are simply a visual aid in quickly establishing normal range on the particular data type?

Precisely. To display any given type of data, the Arduino
1. lights up the appropriate LED's give a visual aid to establish normal needle range
2. Moves the needle to the spot on the range that reflects the current value
3. Writes/scrolls text across a smaller display beneath the round gauge to label the type of data currently on the gauge and a brief synopsis of the key points in the range.

The only reason I choose a tachometer as the display device is because it's so simple to control the tach's needle position from the Arduino.

I envison the system rotating from gauge type to gauge type about every 2 or 3 seconds. So if you'll stare at it for 10 ro 15 seconds you'll see all the various gauge types as it cycles through them.

Further refinements that have occurred to me:

A. Install a push button on the dash right next to the gauge.
-- Hold the push button down for 3 seconds to stop the auto rotating through gauge types. Call it "focus mode."
-- When in focus mode, the same gauge remains on display "forever"
-- Each "normal" push of the button cycles one step forward to the next gauge
---- That allows the driver to choose any gauge he wishes to watch specifically.
-- Hold the button down for 3 seconds to return to "normal" auto-rotating mode.

B. Since the charging light no longer matters to us (we have both a voltage and amperage gauge now) have the charging light become our "Emergency/alert" light.
-- Flash the light if any of the gauges are out of safe range
-- Enter "focus mode" and cycle immediately to the out-of-bounds gauge.

C. If you REALLY want to have it get the driver's attention (Like low oil pressure or high cylinder head temperature) install a relay in the ignition wire controlled by the Arduino. In case of any "full emergency" status, cut out the ignition for 1/2 second once every four seconds or so. The engine will stay running, but the intermittent cutting out will get the driver to look down at the dash, where he will surely notice the flashing red light and the gauge telling him the status of whatever serious issue is going on.
-- Maybe long-press the button for 5 full seconds to ignore the emergency status and stop cutting out the ignition?

I welcome any suggestions/warnings/criticisms.

It seems like it could be pretty useful, and could be infinitely configured to each owner's preferences.

Bob

[propane1]

Cut the grass today with the Case 224 with gadget. Hydraulic Oil temperature was at 70F before I started the tractor. Outside air temperature was 78F. Hydraulic Oil temperature was at 130F when I finished. Idled her down, blew grass off and backed into the garage, oil temp was 119F.

There now, a little ramble.
Have a good up coming week gentlemen.

Noel

Oh, had me Case hat on too,

[Eugen]

I think I'd like myself one of those and see if my 644 overheats when it quits on me