Designing an Engine Oil Temperature Display Gauge Project

[peterbaron]

As for the original idea, spent a few hours measuring the CB's (at least, my CB's...) built-in EOT sensor. The devil is in the details: if the same electronics are to be applied to bikes of different manufacturers, models or even model years, there has to be a guess made on which NTC thermistor is being used. Supply voltage might be different too - just too many variables I'd be comfortable to work with. There are some 50 or so standard NTC series, not sure if I could get a reasonable readout just by guessing. Of course it could be fine-tuned to any specific bike, but that would require some way to input points of the characteristic curve - basically, taking the EOT sensor out, dipping in a cup of hot water, and measuring temperature with resistance changes as the water cools down to room temp. Not something I'd expect to be a standard installation step

Csory, just by following your project and reading your technical notes, I do not see any obstacles for you , knowledgable man in this field = you will do it

[GoldOxide_imp]

As for the original idea, spent a few hours measuring the CB's (at least, my CB's...) built-in EOT sensor. The devil is in the details: if the same electronics are to be applied to bikes of different manufacturers, models or even model years, there has to be a guess made on which NTC thermistor is being used. Supply voltage might be different too - just too many variables I'd be comfortable to work with. There are some 50 or so standard NTC series, not sure if I could get a reasonable readout just by guessing. Of course it could be fine-tuned to any specific bike, but that would require some way to input points of the characteristic curve - basically, taking the EOT sensor out, dipping in a cup of hot water, and measuring temperature with resistance changes as the water cools down to room temp. Not something I'd expect to be a standard installation step

Not to complicate the plan, however, if things like these are a common challenge across bikes, one could consider creating a "common" module where generic I/O is wired to, as well as Vcc and ground. Add a low-cost bluetooth radio and broadcast the raw I/O digital values to a receiver module or phone app that will map the I/O to specific device profiles and display their real-world values - refreshing maybe every one or two seconds.

Since you are only reading the I/O and not controlling anything, this should be completely safe. This would be similar to an OBD device (but read-only), and wiring would be flexible to the end user's need.

- - -

You might be able to cobble together from off-the-shelf sources a low-cost common I/O module (4 port enough?), a bank of cheap ADCs, maybe a low-end MCU, integrate a BT radio and that will allow you to focus your energy on the your receiver module, or just a phone application.

[17-CB-002]

Hi Csory,
For this CB1100 "EOT" I am confident that the resistance/voltage look-up table is accurate, so is the circuitry as described in my original posting.

Let's say that one wants to build a simple temp display with a 3 digit temperature reading and we know the following:
The constant supply voltage "VCC" is 5 volts.
The "EOT" reading is between 0.01 to 4.99 volts.
The "EOT" resistance (NTC) is 50 to 16 K Ohms.
We will temporarily back probe at the back of the "EOT" connector.
We may require a 12volt to 5 volt supply.

Note: The IAT (Intake Air temperature) is an identical circuit also.

Can you draw me the diagram & tell me what components are required?
If prototype is successful, we can get more CB1100 owners interested.

I will try to get the necessary components from my local electronic supplier to build one here in Canada.
Your assistance is appreciated.
Alain Lee

[Csory_imp]

Alain: Attached please find a circuit diagram that would work with a 3-digit 3-segment LED display, and able to read 2 independent analog channels (EOT and IAT), both scaled between 0 and 5V. Impedance is megaohm/ish. Display decoding is done by the MAX7219, analog read and conversion (along with all the pretty stuff) is via the ATTINY85 microcontroller (programmable in plain C). This entire thingy is very similar to my original "gadget", except for ditching the DS18B20 temp sensors, light sensor, and adding a second analog voltage input. Hope this helps.

[Csory_imp]

GoldOxide: I don't know either if this is a common "issue". Putting together an instrument you described should not be a big hassle, but tapping into the wiring could/would (and probably invalidate warranty). Also, there are not that many analog signals I can think of. IAT more-or-less equals to ambient air temp, EOT and ECT might be interesting - what else? Will have to finish the original project anyways - still fiddling with the display...

[GoldOxide_imp]

GoldOxide: I don't know either if this is a common "issue". Putting together an instrument you described should not be a big hassle, but tapping into the wiring could/would (and probably invalidate warranty). Also, there are not that many analog signals I can think of. IAT more-or-less equals to ambient air temp, EOT and ECT might be interesting - what else? Will have to finish the original project anyways - still fiddling with the display...

Sure, I assume warranty was not an issue since I think for most it would have expired by now. Tapping into wiring would be a hassle yes, but there are wiring "T-like crimp devices" that connect to the circuit without cutting or scraping the wiring sheath. I was just thinking if this was an approach, all the taps can be collated at a common I/O concentrator and converted to digital. A four port concentrator probably be enough with future expansion to spare. Generic, but sure, could be overkill. It depends on future ideas I suppose.

[peterbaron]

I am more than certain that all electric techs know about liquid insolation tape, which I used with a great success, mostly in difficult spots or cut insulation. I used proven good brand Wurth, and would advise to use good quality for the best results. Takes time and patience to apply a few coats but results are worth your effort.
'Here is just an example:
https://shop.wurth.ca/adhesives-tapes/ta...93.198010/

[DBM_imp]

I am more than certain that all electric techs know about liquid insolation tape, which I used with a great success, mostly in difficult spots or cut insulation. I used proven good brand Wurth, and would advise to use good quality for the best results. Takes time and patience to apply a few coats but results are worth your effort.
'Here is just an example:
https://shop.wurth.ca/adhesives-tapes/ta...93.198010/

Would it be possible to retrofit a XR650L oil temp gauge filler cap to work on the CB1100 engine case?

[Cormanus]

Good luck finding it, DBM, but I'm pretty sure someone on the forum had an oil temperature gauge in their filler cap and posted pictures of it. I've no idea either where on the forum it is is where they sourced the gauge.

There's this http://cb1100forum.com/forum/showthread.php?tid=6746 and http://cb1100forum.com/forum/showthread.php?tid=8685

[DBM_imp]

Good luck finding it, DBM, but I'm pretty sure someone on the forum had an oil temperature gauge in their filler cap and posted pictures of it. I've no idea either where on the forum it is is where they sourced the gauge.

There's this http://cb1100forum.com/forum/showthread.php?tid=6746 and http://cb1100forum.com/forum/showthread.php?tid=8685

https://www.xrsonly.com/parts-categories...dip-sticks