The HeliPort support thread

[redbird300]

Welcome to the HeliPort support thread.

We intend to create a versatile and portable, digital toolkit for r/c helis, named "HeliPort". Feel free to post any questions you like about the use, development, future releases, bugs or any other subject related to this piece of software.

Ber60, Tjomp, Sutty and myself will be glad to answer your questions. Please read the help screens in HeliPort before posting, they contain information about the use of the individual modules.

Any bug reports, extra information or additional ideas to be used in HeliPort are also greatly appreciated. They will be considered to be added in a later version, which will be announced in this thread.

The latest release and additional information can always be found, and downloaded for free, at
http://www.helisoftware.com/

We hope you enjoy this totally free software. If not, we'll try to change it.

[Ber60]

Yep ready to support

[redbird300]

And a happy announcement: version 0.14 is online, batteries .... i mean, tachometer included.

Remember, this is still a beta version in my eyes, and we'll correct any possible bugs if needed, so let us know what you think about it. And please do read the help text for the tacho.

[WillJames]

Looking GREAT, congratulations on the new version. I stuck this thread for you. Nice work!!!

[Oracus]

Thats cool any video of it being used?

[redbird300]

Originally Posted by Oracus

Thats cool any video of it being used?

I made one, only about an unfinished prototype of the tacho. But it is obsolete now. Cool idea though, I'll make one soon, and post the Youtube link here.

[redbird300]

Originally Posted by WillJames

Looking GREAT, congratulations on the new version. I stuck this thread for you. Nice work!!!

Thanks Will. I hope this thread will prove to be useful. New versions should come out every few weeks now. I guess when we'll be at release 0.20, it will be finished, with the tools that are described at the actual site. That will be the moment to call it version 1.00. But there are many more ideas to realise and add...

[redbird300]

First little error found in the headspeed calculator: the Rave 450 main gear seems to have 177 teeth as I have been told, it's set at 150 in HeliPort now. Will be corrected soon. :o

[redbird300]

Version 0.14 has been online for a full day now, and we made some short announcements in several places about it. As a result, the webcounter reveals over 450 unique visitors from 29 different countries during the last 24 hours, that's not too bad for an unfinished beta release.

[copterboy]

Ahh, so this is what I missed last night!!

Congrats on a fine piece of software Raf, and everyone else who helped test ofcourse.

Version 0.14 downloaded, gonna try the tach on my t-rex now. Would any of the data help you out from that?

[Z900]

Run it on my HTC HD2.....

Could your Tach Tool work with sound from a video camera movie, Raf?
Or better real live sound from the heli ?

I used videosound of my Trex700N -> 3593rpm several times (seems about x2)

It's a crime to shut down HeliPort0.14...damn !

[Tjomp]

Originally Posted by Z900

Run it on my HTC HD2.....

Could your Tach Tool work with sound from a video camera movie, Raf?
Or better real live sound from the heli ?

I used videosound of my Trex700N -> 3593rpm several times (seems about x2)

It's a crime to shut down HeliPort0.14...damn !

The tacho tool is meant to work with real live sound from the heli. That is, it is recording 2 seconds of sound and then analyze it. If you mean realtime as in showing the current RPM all the time I am afraid that will pose a problem.

You can use sounds from other sources like a video and feed it to Heliport for RPM analysis. You would need to use something like Audacity to extract the sound and save as an 8bit wav file in 11025 hz bitrate. The file needs to be named "tacho.wav" and you must put it in Heliports folder. Then you go to the tacho tool and hit the RPM button. Don´t press the record button as that would overwrite your file.

The Tacho tool is really meant to be used on electric helis. It´s measuring with sound by nature and the loud noise of your nitro engine could confuse the measurement. But don´t despair. Try to take a look at the spectrum and see if any of the other values the tool have picked up is more in line with what you expect.

[sutty]

Hello Z900,

Raf has asked if myself, Tjomp and Ber60 can address questions posed in this thread, unless of course we cannot provide the answer.

Thank you for your question and I will do my best to answer, but of course if it requires further investigation, then we can direct the question to Raf himself. It should be said that much of the following is available in the help menus but I guess it doesn't hurt to put this in this thread at least once.

Firstly, the tachometer in HeliPort is indeed meant to be used with real recordings of your helicopter, this was the primary design motivation. The ability to analyse existing recordings is, shall we say, almost a bonus. The idea is to set a delay, let's say 30 seconds, press the record button, and then hover within a few metres or so of your device, pda or laptop, safely of course, ensuring that you do so for enough time for the 2 second recording to be made. In this example you would have to hover until 32 seconds after you pressed the button.

After you have landed, and secured your heli, you can then press the play button to listen to the recording of your heli, to make sure it has been correctly recorded. If it hasn't then you would need to check your device settings and try again until you have a successful recording. If you can hear it, and it sounds like what you might expect, which of course it should do, you can then go on to press the RPM button, and the RPM value will be displayed.

If it is close to your expected value, most people have a good idea of what to expect, then you can be confident that this is the actual RPM of your heli. If you get a result that is likely to be erroneous, based on your prior knowledge, then you should press the spectrum button, and look to the values displayed and their relative amplitudes. From this you will almost certainly find another value, as you say at about half your displayed result, with an amplitude that is lower than the one picked out by HeliPort. Results such as this can occur if the amplitude of a harmonic of the actual value is higher than that of the actual blade speed itself.

Other tools often require you to already estimate the value for your headspeed, in order that the tool can ignore any possible stong harmonics. In the case of HeliPort, Raf decided that he would prefer it if this pre-assessment of headspeed could be avoided as in the vast majority of cases HeliPort will report the correct headspeed anyway. In the case of an obvious error, the spectrum should also display the correct RPM, but at a lower amplitude than the value originally reported.

Since the tool is not primarily designed to analyse existing recordings, but those recorded in HeliPort itself, we have found that under such circumstances it is more likely to give an error in the displayed value than when the recording is actually made by HeliPort. In these circumstances however the correct value should be found in the spectrum, and since most, including you, have a knowledge of what value to expect, then you can easily pick out the true RPM value.

There are several reasons why a pre-recorded sample may be more likely to yield one of the harmonics of the true blade speed rather than the blade speed itself, such as problems caused by additional signal processing and compression, and the distance the original recording was made from, plus others that Raf has mentioned to me, but that I am not sufficiently versed in the technicalities to be able to help you in this regard.

Please let us know the result of checking the spectrum, and if there is no alternate clear value displayed, perhaps you could zip up your sample and e-mail it to the HeliPort support team so we can take a look at it for you, and try to better understand why it did not report the correct value.

As for your last comment, I am a little unclear as to what you mean, perhaps you could clarify so that we can address this point too.

Thanks for taking an interest in the HeliPort tool, I hope it proves to be a useful tool for you.

Regards


Sutty

[sutty]

Hey Tjomp, we doubled up, sorry about that. I babbled on as usual, whilst failing to notice that it was a recording of a Nitro.

Cheers

Sutty

[copterboy]

Well I just tested V0.14 on my laptop and belt-cp and t-rex, and I don't think heliport is making a proper recording on my laptop, if at all. Aparently, my belt has a higher headspeed than my t-rex, and the specktrums are all over the place like an earthquake detector - no clear peaks at all!!!

I am being stupid here? How does heliport know which mic to use on my laptop to make the recording for example? I'm indoors about 2m's away from the heli. No doubt I'll try it outdoors in the morning at the recommended distance of 5 to 10 m's, but your thought's are welcome.

Turn the kettle off Sutty I'll be checking in the morning so you don't have to stay up late for a response.

[sutty]

I probably got a bit giddy with 5-10 m, that is what I have tried, and have been successful, I'll change the post to read within a few metres.

Not sure about the mics, Tjomp or Raf will know, I expect it is the mic you have set as the default under windows.

All of the recordings I have made have had mainly one or sometimes two clearly defined peaks, so maybe there is a hardware issue there? What does the recording sound like? Mine sound just like I would expect, if you see what I mean.

Cheers


Sutty
EDIT: As for the time, don't worry about that, I never go to bed early, and this extra hour is really going to mess me up. Great for heli flying in the evenings though.

[Ber60]

Copterboy can you post a pic of the spectrum of your recording because I think you may try to get a rpm of "static noise"

[redbird300]

Perfectly said Sut, thanks. Couldn't have done this any better.

Allow me to look at a few possible "weird" scenarios when using the tacho:

1) Recording with no mic connected, or at least no mic that is recognized by Windows:
Depending on your setup, the first possibility is that HeliPort will pick up no signal at all, resulting in a zero RPM value, which is logical. BTW, this whould be the only time that you'll see the needle of the tachometer at zero RPM. Second possibility: depending on the quality of the wiring in your PC, HeliPort will pick up some very weak noise, and will analyse the strongest frequency in that weak noise. That can easily be seen in the spectrum, as the amplitude values will be very low (tens or hundreds). Normal recordings should show amplitude values like thousands or tens of thousands. Remember that the spectrum graph is auto-scaling on the Y-axis, so the physical heigth of the peaks is not relevant, you should look to the numbers on the Y-axis and the frequency list !
2) Recording with several mics connected:
HeliPort will try to recognize the default Windows mic indeed, but it might be wise to avoid these weird situations anyway, I never tested with several mics at once, it simply didn't make sense for me.
3) Recording while your sound driver is setup with some filters, acoustic suppression or equalizers enabled:
This is a default setting in many computers, simply turn off all this stuff in your configuration screen.
It is like mutilating the signal, even before it can reach HeliPort. it might not hurt, but you never know.
4) Holding the mic extremely close to he main blades:
The wind will activate the microphone membrane, at weird speeds. Even over a small distance, the wind is slowed down a lot before it reaches the mic, and the turbulence will cause it never to be in line with the frequencies we want. It is like blowing in the mic, and expecting it reports RPMs of a heli that happens to be around. You want to record the real sound of the main blades, not a storm passing by, lol.
5) Trying to measure RPM on a nitro heli:
This does not work, it is not intended ! The loud engine will cause lots of harmonics, disturbing the values between 1000 and 5000 RPM. I will make a special nitro mode in the tacho later on, or even a dedicated nitro tacho if I would find the time, forget it for now.

Some of this stuff is also mentioned in the help screen, please read it. I know the user interface looks very simple, but make no mistake, what happens behind the screens demands to be used correctly.

Send me the problematic sound file in case of any more questions, I can see a lot more in these as anyone else. I can do much more analysis, and look at it in depth, even be able to tell you what happened in some cases, there is a lot of hidden information in these files that HeliPort won't show you.

Let us know how it ends, there has been a lot of testing before I released this tacho, it should work nicely.

[redbird300]

I'd like to get some feedback about 2 small ideas I have concerning the user interface of the tacho:

1) When recording, the 3 other buttons (play, RPM and Spectrum) are in fact disabled now, and enabled again when the recording (timed or not) is finished. Wouldn't it be better to make these 3 buttons disappear completely during the recording, and make them appear again when the recording is complete, of course.
This would show clearly that HeliPort is recording, and it would avoid a user to try to push the other buttons while recording, and would also give a clear indication that the recording is finished, because the 3 buttons will become visible again at that moment. (There is no use in adding an audible warning, with a running heli nearby)

2) The button Spectrum is disabled now, and the label "Spectrum" above it is invisible as long as the RPM calculation has not been executed. This button could be invisible instead of simply being disabled, making it more clear for the user that there is no spectrum graph available yet, simply because he didn't ask for the RPM calculation yet.

What do guys you think ?

[sutty]

I'll be honest Raf and say simply that it couldn't hurt, but to be fair I haven't had any trouble in this regard as it seemed fairly clear to me that it was busy, during the timer and record mode as there was an egg timer. Plus I was too busy trying to get my heli airborne in time to be watching too closely. What I couldn't really tell was if it had started or finished recording, without me taking my eyes off my heli. Certainly a visual cue such as this would help, as it would literally be 'At a glance', but I managed anyway by simply flying for way in excess of what was required.

As you know, the fact that the spectrum option disappeared was the one that confused me, not the other way around. Oops, read the manual. An invisible button would have stopped me trying to press it though.

As for the beep, I'm not sure I agree, but then again I know nothing about how hard it would be to code etc. When I did some tests the other day, I had my laptop on a little table next to me, and I am pretty sure I would have been able to hear a beep. Then again I can see that this would be far less likely to be heard on a PDA. Anyway, if you were to consider this, then it could perhaps go Beep, Beep, Beep, Beeeeeeeeep, when it is about to record.

Cheers

Sutty