Mikrokopter servo issues FC 2.1

[anaka]

Hi MK people

i'm trying to build my own retractable landing gear and I have some problems

i bought the following kit
http://www.epf.com.tw/goods.php?id=3

this kit has a central unit that controls the behavior of the actuators interpreting the signal received by the transmitter

i connected it to the FC of my MK, i configured the servo3 exit on MK tool

and I got no results...

if i try the kit with a servo tester all works fine
if I try standard servos (both analog and digital) they work fine with the FC and servo3 exit

i can't explain why the kit doesn't work with FC...the central unit lights on it's LED but that's all it does

i also tried it with crappy 2 channles car kit receiver and it works well

can someone help me?!?

 

[ovdt]

Hello anaka,

What's the amp draw of the retractable landing gear? I wouldn't recommend to get the power of the landing gears. Provide the power with UBEC, and get the signal from the MK.

 

[anaka]

hi odtv
i forgot to mention that...i'm using just the signal from the FC and powering the gear with 6.0 V, maybe will go for 7.4 V to make it faster

the Working current is 0.09A

 

[Bartman]

do you have a ground wire going to the retract servo with the signal? the grounds have to be common or the signal won't do anything.

 

[anaka]

hi bartman

no i don't have the ground from the signal but only from the power
I understand what you mean and I verified the ground presence using a standard servo

the servo works well, it gets the signal and follows the commands that i send trough the servo3 channel

so after this test i unplugged the servo and connected the retracts but they don't work

the overall feeling is that the FC uses a signal that in some ways is not recognized by the retracts unit

BTW i'll try your solution tomorrow, just in case

 

[Bartman]

the plug you have from the servo output has one signal wire, and then one positive and one ground from your BEC circuit? is the BEC ground common to the FC grounds?

what is the output voltage of the BEC? looking at the unit you specified in the first post it looks like it needs 6-7.4 volts which is more than a typical servo just to make it move.

common ground and sufficient voltage would be my next two items to check. good luck with it.

 

[anaka]

ok guys a little update

i'm measuring all the possible values with a standard digital multimeter and the Hitech HFP-25 (servo programmer and tester)
http://www.servocity.com/html/hfp-25_servo_programmer.html
this servo programmer has also the ability to read values from receivers so i can easily check the values i need

the circuit i developed is made in the following way:

the BEC gets the power from the Extension-PCB https://www.mikrocontroller.com/ind...id=576&zenid=45b81f319e911602d47ca14119352163
the ground cable is common, I verified this with the miltimeter, plugging the ground on the BEC and the signal on the servo3 exit on the FC the multimeter reads values so the current passes

with the servo programmer I measured the MK FC signal range, I drive the signal with a futaba T9FG transmitter using a 3 position switch, from the FC I get 683 low value, 1499 middle value, 2321 high value for pulse signal in micro seconds

this signal activates without any problem all the servos i have but if i try it on the retractable gear system it has no effect

i tested separately the retractable gear with the servo programmer and it works fine, the pulse signal range that open and closes the actuators is from 1315 to 1425 micro seconds, this range is much smaller than the one coming from the FC, this means that the FC signal is wide enough to activate the retracts but it doesn't happen

 

[Bartman]

anaka, what voltage is being supplied to the retracts' controller?

 

[anaka]

a the moment the BEC is set to 7.0 V and it powers both the controller and retracts

I did also tests with the BEC at 6.0 V without any result

when i use the servo programmer the volgate is 6.0 V only

 

[Bartman]

a the moment the BEC is set to 7.0 V and it powers both the controller and retracts

I did also tests with the BEC at 6.0 V without any result

when i use the servo programmer the volgate is 6.0 V only

bad controller then?

 

[anaka]

that was my first impression...bad controller

but i made tests with some standard receivers before to test it with the servo programmer, one of them was a 2 channel receiver for cars powered at 6.0 V
it works ever..

it stops working only if i plug it on the MK FC

 

[Bartman]

is the MK FC maybe sending a signal outside of the range of the controller? does the controller need to be up or down to be initiated maybe and the signal is opposite that?

i'm running out of wild-*** guesses?!?!

 

[anaka]

ok the FC has problems

i'm investigating, it looks that there are problems with one resistor

hope that i can find quickly a substitute...

 

[Bartman]

ok the FC has problems

i'm investigating, it looks that there are problems with one resistor

hope that i can find quickly a substitute...

do you need another FC 2.2? I've got one that just came off of a brand new build, it's only got a few test flights on it and it's for sale.

where are you located?

bart

 

[anaka]

i'm in italy

i can be interested to your offer
i just wrote to MK team to know how expensive could be to fix it
once they answer me i'll contact you quickly

in the meantime if you want to p.m. me with your offer i'll be happy to valuate it

thanks

Augusto