Motors arm immediately on power-on, then do nothing

[3.14159]

Building a quadcopter with the following specs, and having the weirdest of issues that has me baffled.

MultiWii 2.3 on an Arduino Uno (functionally a Pro Mini), with a DIY shield to connect everything together
Turnigy Plush 20A ESCs
800KV motors
Spektrum AR610 RX
Spektrum DX5e TX
GY80 IMU

MultiWii has been uploaded to the Arduino.
RX has been connected to the correct pins as per the connection diagram on the connecting elements page of multiwii.com, as have the ESCs.

I am able to connect to the Arduino via MultiWiiConf, and see the current orientation, heading etc of the quad. I can also see the sliders from the TX moving, so I am sure thats working.

The problem is: as soon as I power up the quad (literally connect the battery to the power harness), the ESCs make their 3 startup beeps (as normal), then immediately proceed to arm (4 beeps, as I have a 4S lipo). This is regardless of whatever state the TX throttle is in (switched on and bound to the RX). After this the motors do absolutely nothing. I'm sure the TX and RX are working as I can see them move the sliders.

So far I've tried:

Calibrating ESCs one at a time with TX and RX (power up an ESC, after 2 beeps move throttle from high to low, hear 3 beeps) - no success (Its worth nothing with this attempt the the TX controlled the motors flawlessly when connected directly to the RX during this.)

Uncommented ESC_CALIB_CANNOT_FLY (powered up quad, moved throttle from high to low, recommented and reflashed) - no success

I checked the signals coming off the RX and motor pins using my oscilloscope, and got the following

RX output (varied with TX throttle)


Motor output pin (all are the same, and this is always fixed)


Extra details:
I found that the motors started turning when the throttle was at 1065

Current config settings are:
#define MINTHROTTLE 1150 (tried 1065) with no change
#define MAXTHROTTLE 1850
#define MINCOMMAND 1000

full config is here: http://pastebin.com/7xMmpnLy but I dont think there is anything special there

Has anyone got any clue what to do?

[waltr]

Did you properly setup the transmitter's stick center and end points?
This MUST be correct and is the very first step in MW setup.
Those scope traces are no help at all except to tell us you looked at those signals.

[3.14159]

I checked to make sure they were all 1500 when the sticks were left alone. They seemed to be 1498-1500. Do you have a link to instructions so that I can double check?
I checked the signals just to make sure some change was being registered somewhere. Surely the latter trace helps verify that that is a problem with MW rather than the ESC?

[waltr]

Use the MW gui to verify the Channel values from the TX/RX. 1498-1500 centered is normal but you may need to enable the DEADBAND in config.h
What are the stick End Point values????
Without knowing what the O'scope scale is (V/div and Time/div) all this shows is that there is a signal but nothing about how correct the signal is.


ESC 4 beeps = ARM??? Or does this just mean that the ESCs are now seeing a proper pulse?
ARMing is done with a stick command and ARM's the FC. Have you done this?? If the FC is not ARM'ed then it will not change the pulse width to the ESCs.
All this is standard MW.

[3.14159]

I think that the problem was coming more from a misunderstanding of arming on my part. I was under the impression that the an ESC was armed after it had powered on and beeped according to the number of cells detects powering it. I didn't realise that MW distinguishes this from its own arming procedure, as this was never made clear anywhere. To add to this, I hadn't realised that MINCHECK existed, and I think that was causing more problems, since I had tried the MW arming stick command just to see if anything would happen, and it didn't (which therefore lead me to believe the ESCs themselves were armed but not responding). Anyway, I've altered MINCHECK and MAXCHECK now as well, and can successfully arm and disarm the quad with the appropriate stick commands. Things seem to be going ok now, thanks for helping me out!

[waltr]

Ok, mod'ing MINCHECK and MAXCHECK is required on some TX's. You need to first try the TX setup and adjust the stick End Pint to get 1000 to 2000 as seen in MW gui. If you can then the default MIN/MAXCHECK values are ok. If not then they needed changes as you did.

Did you read the Beginner's thread here? It has lots of good info and some links.

[3.14159]

Ok, that sounds good. I can now get the throttle value on the MW GUI to read from 1000 to 1900 (it doesn't seem to go higher, probably because MAXTHROTTLE is set to 1900, but this doesn't seem to be affecting anything adversely...)
I haven't read that thread. Can you give me a link to it? I couldn't find any sticky posts on the forum.

[waltr]

MAXTHROTTLE has nothing to do with the values from the TX as seen in the MWcondif.exe.
Will be ARM now?
What are the other stick End Point values and their center values? These need to be 1000 -2000, centered at 1500.

Study this tutorial:
http://witespyquad.gostorego.com/videos.html
Beginners Thread
viewtopic.php?f=18&t=5363

[3.14159]

It will arm when throttle is below 1065, and yaw is maxed out.
I think I have the endpoints centred correctly, and they centre at around 1500.
Overall, things seem to be working. It just ironing out the small problems now.
Thanks for all your help! I will read through the threads you've linked to.

[abacusalanya]

Why are you using GY80IMU ?

[3.14159]

Went for it does it had everything I needed, it was cheap, and it used well known chips that there was existing support/libraries for.