Ppm + compile sketch

Hi Folks,

iam new in the classic narrow universe.

this evening i have startet binding my new little quad the first time.

It binds but nothing more.
i have bought this receiver:

but i cant see any output from my sender in the multiwii :frowning:

now i have looked in the sketch but i cant compile it.
Arduino: 1.6.9 (Windows 7), Board: “Arduino Leonardo”

sketch\IMU.cpp: In function ‘void getEstimatedAttitude()’:

IMU.cpp:212: error: ‘GYRO_SCALE’ was not declared in this scope

scale = (currentT - previousT) * (GYRO_SCALE * 65536);


exit status 1
’GYRO_SCALE’ was not declared in this scope

Dieser Bericht wäre detaillierter, wenn die Option
"Ausführliche Ausgabe während der Kompilierung"
in Datei -> Voreinstellungen aktiviert wäre.

Any Ideas whats wrong with my setup?

Hello @n3ro. Please have a look at this link if this is an AlienFlight 5v side USB and it will give the full details of how to properly set up the card. If this is not one of the newer AlienFlight and an AlienWii it should still help you to get that set up properly. Did you calibrate the ACC first thing before doing anything? That is the first thing you want to do when you connect to the MultiWii GUI. It will orient the gyro so it knows up from down and sideways. If it is not calibrated the FC will not know what is what. Here is a link to the thread that shows how one should be set up so that it will work properly:

Hi :slight_smile: and thx.

The ACC is calibrated and i can see all the gyro information in the GUI.

My receiver supports only PPM output. i have to change this in the sketch right?

This are my parts
newest alienflieght classic narrow
dsmx receiver with ppm
9xr pro with orangerx transmitter

at the moment i have done no changes on the remote (its my first device)
and the sketch didnt compile but i have all files from the tut

I will have to admit that I am not very knowledgeable in how to use ppm for these since it is rare that anyone does. It is reported that the ppm signal is inferior to the Rx serial connection. That is because from what I have read this is an analogue signal that is about 3 times slower than a Serial Rx. There are defines in the config.h files of the sketch if you open it in arduino they are about 1/3 of the way down the page. If you use the PPM there are also 3 pads on the bottom of the FC which designate which signal you use and they are set up for serial Rx vs the PPM. So you would need to unbridge the two pads on the right marked Rx and SRX then connect the two on the left which are PPM and RX. Since I have never used the PPM Rx I am not sure what else needs to be done in order to make it work correctly but for sure you need to comment back the DSM2 setting in the config.h file of the sketch and then uncomment the correct ppm command. Commenting means placing // just before the command line and uncommenting which makes that setting active is removing the // from the beginning of the line. So in a nutshell I am not sure how it works specifically because I have not used the PPM before. Let me see if calling out some of the other members of the forum can help get you a better answer. @Denovich, @chrisdo, @las, @Chaotix any input on this guys??

CFor all that multiwii and arduino stuff I’m certainly not as knowledgeable as @madman1412, @pedro147, @mj666, @Benedikt, @Ulix and others.
I managed to get my :alien:Wii classic narrow in the air, but don’t remember what I did. It’s still flying great.
Never flashed a scetch or did sth similar. That’s way over my head and I’m too lazy to learn all that stuff in times of Betaflight (shame on me).

Also I have minor experience with ppm receivers.
Recently I messed around with beecore FCs which whyever have onboard dsm2 ppm rxs. But that was on Betaflight too.
All I can say ppm sucks.

Long story short @n3ro I would recommend to get a proper dsmx or dsm2 receiver which works with serial rx.
Those lemon ones are reliable and not that expensive.

Can anybody shed light on other available (non ppm) dsm micro receivers?
Let me know.


I have never looked past Lemon sorry @chrisdo they are cheap, reliable and easily available.

As far as I am concerned, choosing a Lemon RX is a no brainer :grinning:


There is a redcon dsmx rx available on BG that I’ve used successfully but it’s only slightly cheaper than a lemon which I can get next day from my local dealer. A dual antenna lemonrx dsmx in uk can be had for £9 at the moment.
Unfortunately I can’t be of much assistance with multiwii and second the ppm is rubbish opinion.

1 Like

Do yourself a favor and get a dsmx sat. Bind at 11ms for the lowest latency connection in the hobby. PPM is way (3x) slower. You will get more accurate, higher resolution control and your quad will fly better. Worthy upgrade.

1 Like

Thx at all!

I have ordered a lemon rx. I hope I can bring my quad in the air with it :slight_smile:

1 Like

Well, I guess the consensus here says why I do not know how to make the PPM work. With a Lemon Rx such as the LM0001 you will not have to change anything in the sketch. Thanks for coming in to help answer the question guys :wink: And @n3ro when you get the lemon and ready to get that up and going just post if you have some trouble. Most common issue is having to increase the travel adjust in your transmitter so that the outputs of the channels reach the min max settings in the sketch which will be 1000=min 2000=max. Also for these FC you need to reverse two channels which would be Aileron and Elevator, you can review that in the link above.

For the change it happens in the Config H, see attached image

1 Like