MiniHub+ - S.Port Telemetry Hub for Frsky Radios - Page 6 - RC Groups
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Oct 26, 2017, 07:20 PM
If it has wings it will fly...
ckleanth's Avatar
Quote:
Originally Posted by Wildvortex
So, I can come off the battery with a Y and into the voltage divider then the minihub. Then just adjust the TX until it matches the 2s battery. Sounds great. Thanks.
yes thats correct.

Quote:
Originally Posted by Wildvortex
Since my engine is a side exhaust it would place the thermistor in the path of the wind coming through my cowl. I will try it as is and see how it goes. I have a IR thermometer and will compare temps.
one note, a temp sensor (thermistor) is a variable resistor that changes internal resistance with temperature. for a temp sensor it does not matter if you place it in an air stream or not (assume we don't cool the sensor down with convection)
now if you place the temp sensor on a hot cylinder surface, it will measure the temp the surface is.
now imagine there is an air stream around the hot cylinder surface, air flows around the tube and as explained before heat is lost through conduction (surface in contact with the air). now if you measure temperatures, on the front where the air stream hits it will be the coolest area, on the sides hotter and on the back the hottest.

in our application, honestly fit it under the exhaust port (or near it) and run your engine. in my engines I try to run them the most up to 140C.
Last edited by ckleanth; Oct 26, 2017 at 08:11 PM.
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Oct 26, 2017, 07:45 PM
If it has wings it will fly...
ckleanth's Avatar
Quote:
Originally Posted by Joetrin
Respectfully Mr. Ckleanth,

Firstly, I call BS, I've been building race cars for over 30 years, and been flying Gas for the same amount of time, I also run a racing organisation, yes full scale race cars on real race tracks for over 17 years (www.spda-online.ca)

I suggest you stick with what you know, even the original owner of N2 Industries (the guy you bought it from, Chuck) had ring terminal Temp Sensors, Just letting you know. Here are some corrections to the previous post.

Timing is set at 28 BTDC
As a professional that's trying to sell a sensor hub, it would be good NOT to spread FUD (Fear Uncertaintly and Doubt) if you don't know what you're talking about.

This was the sensor that was sold by the person that originally made and sold N2 Sensor Hubs (Chuck).

My race cars all have Autronic Engine Mangement systems, and i do Index the plugs to get that .000001 percent better burn.

Just letting you know the facts. My EME120 and RCGF70's all use CM6 plugs and use .5mm Copper ring terminals for temp measurements. I also use NTC 3950B Thermistors and I've loaded OpenXSensor onto the N2 Industries Sensor Hub and corrected the Slow RPM and SLow temp readings by using the HW interrupts for RPM.

Temp sensors fit between the fins, not on the fins, and must be as close to the cylinder walls as possible and closest to the top of the engine (hottest point).

I now use the Applied Telematix Sensor Hubs, as they have 3 temp probes for multi cylinder engines and up to 5 temp probes. Do yourself a test, put one Temp sensor near the exhaust port and notice how variable it gets, then put one in between the top most fins close to the cylinder wall and see how stable the readings are. Prove it to yourself, don't listen to either one of us.
as a professional (PhD chartered mechanical engineer that has worked in the automotive industry and now aerospace) with specialization in thermodynamics, fluid mechanics and mechanical vibrations it is my personal opinion that in our application (rc planes) it does not worth the effort messing with the spark..
I want to have a relative indication if my engine is under baffled or I have pushed it too hard therefore it gets hot, It is not my intention to measure what temperature the spark is at, because this is where combustion happens, I know pretty much what temperature the exhaust gases are at without measuring, but I want to know what temperature the engine casing is at.

the old N2 industries hub had a code fuckup and had the slow rpm and A2 heavy filleting (temp measuring was fine). The said fuckup of the old code is now fixed.

you are confusing model toy planes with race cars that have EFI and ECU mapping. until we have EFI units in our engines we have no control how the engine operates. All we try to do is to have an indication if the engine gets hot (or not).

I still think the temp sensor with ring is not a good idea, hence I'm not recommending it but by all means nobody is stopping you from doing it. I just dont see the point.

btw the name is George
Oct 26, 2017, 07:47 PM
Registered User
Joetrin's Avatar
We can agree to disagree.

Thank you
Oct 26, 2017, 08:23 PM
If it has wings it will fly...
ckleanth's Avatar
Quote:
Originally Posted by Joetrin
We can agree to disagree.

Thank you
Indeed. No worries.
Nov 09, 2017, 07:23 AM
Registered User
George, I am not sure if it is a setting that I need to make for my tempiture sensor or what is going on but while the engine is room temperature the transmitter shows that temperature. I flew last Sunday and when I looked to see the temperature it was off the charts somewhere in the hundreds of thousands. Definitely hot enough to melt not just the aluminum but even the steel.

I thought I got a picture of the telemetry screen while on the ground but I can find it. As I just had my appendix out I won't be able to get a shot of it for a couple weeks if you need one.

Steve
Nov 09, 2017, 06:14 PM
Can it fly? I'll try and see!
ryane67's Avatar
Quote:
Originally Posted by Wildvortex
George, I am not sure if it is a setting that I need to make for my tempiture sensor or what is going on but while the engine is room temperature the transmitter shows that temperature. I flew last Sunday and when I looked to see the temperature it was off the charts somewhere in the hundreds of thousands. Definitely hot enough to melt not just the aluminum but even the steel.

I thought I got a picture of the telemetry screen while on the ground but I can find it. As I just had my appendix out I won't be able to get a shot of it for a couple weeks if you need one.

Steve
I was getting that too when displaying temp+, are you using a taranis or horus?
Nov 10, 2017, 09:20 AM
Registered User
brtman's Avatar
me too ! Horus. opentx 2.2
Nov 10, 2017, 10:34 AM
Can it fly? I'll try and see!
ryane67's Avatar
I never got around to logging my telemetry data to SD card to see what's happening here because I was more focused on my sailplanes for the latter part of the flying season, but that would tell us for sure.

I'd guess that if we look at temp in logs and compare it to temp+ over time, there is probably a tiny spike in the temp log, but obviously it causes temp+ to stay up there forever. The question now is whether it's in opentx or if it's a question of what the minihub is sending.

In either case, it could mean that the sensor tracking needs an output or input filter applied so it cannot change more than something like 50% over 1 second.
Nov 10, 2017, 10:19 PM
If it has wings it will fly...
ckleanth's Avatar
Quote:
Originally Posted by Wildvortex
George, I am not sure if it is a setting that I need to make for my tempiture sensor or what is going on but while the engine is room temperature the transmitter shows that temperature. I flew last Sunday and when I looked to see the temperature it was off the charts somewhere in the hundreds of thousands. Definitely hot enough to melt not just the aluminum but even the steel.

I thought I got a picture of the telemetry screen while on the ground but I can find it. As I just had my appendix out I won't be able to get a shot of it for a couple weeks if you need one.

Steve
Hi Steve,

Did you use the 10K thermistor pin (see attached picture how you should connect a 100K thermistor like the one that comes with the minihub or the frsky TEMPS1).

Note the new minihub does not work with OTX 2.0.x, it needs OTX 2.1.x onwards.

I'm working towards updating the manual (with the other stuff I got to do) and clarification regarding the temperature pins this is one of the things that needs to go in.

regarding the temp+ I don't use it but I do save the logs from my planes but I never recall to see a massive spike onto any of them.
Last edited by ckleanth; Nov 10, 2017 at 10:26 PM.
Nov 11, 2017, 06:54 AM
Registered User
Quote:
Originally Posted by ryane67
I was getting that too when displaying temp+, are you using a taranis or horus?
I am running Taranis. Can't remember what version of firmware.
Nov 11, 2017, 07:00 AM
Registered User
Quote:
Originally Posted by ckleanth
Hi Steve,

Did you use the 10K thermistor pin (see attached picture how you should connect a 100K thermistor like the one that comes with the minihub or the frsky TEMPS1).

Note the new minihub does not work with OTX 2.0.x, it needs OTX 2.1.x onwards.

I'm working towards updating the manual (with the other stuff I got to do) and clarification regarding the temperature pins this is one of the things that needs to go in.

regarding the temp+ I don't use it but I do save the logs from my planes but I never recall to see a massive spike onto any of them.
I'm not quite sure what pin I used when setting it up. Likewise at the moment I don't know what version of firmware I am running. I probably won't know for a week on the pin I used. The plane is hanging on the wall and I just had surgery so I can't lift it off. I'll check on the Taranis soon
Nov 11, 2017, 07:37 AM
Registered User
brtman's Avatar
I'm running two frsky temps and it is happening on just one sensor. Not on a calculated cell ( temp+ ). Both were at 74 degrees on attempted startup. One was reading like hundred thousands after attempted start. Have not investigated further yet. Rediscovered several times.
Nov 11, 2017, 09:05 AM
Registered User
Well, I did get to my TX to check firmware and I am running 2.1.9 so I'll have to update firmware later today.
Nov 11, 2017, 10:35 AM
If it has wings it will fly...
ckleanth's Avatar
Quote:
Originally Posted by brtman
I'm running two frsky temps and it is happening on just one sensor. Not on a calculated cell ( temp+ ). Both were at 74 degrees on attempted startup. One was reading like hundred thousands after attempted start. Have not investigated further yet. Rediscovered several times.
It maybe the sensor at fault or you used the wrong pin and readouts were erroneous. But definitely otx has to be 2.1.x onwards.

I had a mate chatting with him over temperature measures, he was getting like -25C & i couldn't figure out why for one day. I was about to send him another device that i already plugged in and verified it works when he saw the picture of my setup. He used the 10K pin instead of the 100K.
Nov 11, 2017, 11:39 AM
Can it fly? I'll try and see!
ryane67's Avatar
George is that's the case why would it read normal some of the time and only spike sometimes? Wouldn't it always read high if it were the wrong sensor?


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