I have been flying helis for about 18 months, initially on a Trex500 but now I have managed to get a Trex600n and i have a problem. I cannot afford to buy the Spirit Pro for the forseeable future and so I am using my Spirit black edition, I need the development team to, if at all possible, write me a modified firmware to give a 'switched output' on the Rud ch. I need this to operate the CDI ignition that I have fitted to my Nitro motor remotely for safety.
My wiring is as follows; - Aux - Throttle servo with Y lead to power Spektrum 4649t telemetry receiver, signal to Ail pin on the end connection. Ch1 - Ail servo with Y lead to Bec 1. Ch2 - Elev servo with Y lead to Optipower backup device. Ch3 - Pitch servo with Y lead to Bec 2. Ch4 rudder servo with Y lead to power governor sensor, signal to pitch pin on end connector. I am running a Spektrum DSMX satellite receiver in the native socket of the Spirit unit.
I have the unit configured fine but am wary of using without remote arming / disarming of the CDI ignition, Why did I convert a 'perfectly good' glow motor to spark ignition I hear you ask, well , because I wanted better fuel economy, smoother Idle and less oil / goo / exhaust residue is my reason.
I have tried to get a response by messaging the team directly but have got nothing from 3 attempts, what has happened to the legendary customer service ?
Please help me.
Regards
Steve E

Hello,

I am afraid but technically it is not possible. The RUD is shared with AIL pin when using SPM4649T for bidirectional communication. So using it for a different purpose is unfortunately not possible.
Possibly you can use another receiver (with no telemetry) which can receive your your commands and sent them to outputs. So that you will have two receivers. Alternatively you can use just normal receiver only with enough outputs.

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Spirit System developer

Tomas,
Thanks for your reply, as you say i can't use the Rud ch for a switched output as it is linked to the Ail pin, can you then have a switched output on Ch4 instead ? I really need to have this function to safely control the CDI ignition remotely via an Opto isolated kill switch.
Thanks again.

Hello,

for RUD this could be possible if you just wish to turn on and off the output.
But the signal from this pin has PWM modulation.

How you are driving the CDI?

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Spirit System developer

Tomas and team,
I have got the 'Rcexl V2.0 Opto gas engine kill switch' to switch the ignition off, The ignition itself is powered from a 3S lipo that also powers the Bec.
I have enclosed the instructions for your information, hopefully this will help, I am using the same system as the upper illustration in the instructions.
Thanks again,
Steve E

Hi again Tomas and team,

I have just tested the Opto isolated Cdi switch with my servo tester, it seems to be a simple 'PWM' operated switch as you thought. Does that make it possible ? I hope so.
Kind regards,
Steve E

Hi,

I am very sorry but any pin can't be used to drive two things separately. The PWM signal must be driven from two pins and not each pin of the unit can be used for PWM output.
The signal could be just same as for the Rudder.
So either your rudder will not work or your CDI.

I am afraid but you have to buy at least other receiver. You can get very cheap clones but Spektrum full size receiver would be the best. So you will need just maybe 10 USD to resolve the problem.

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Spirit System developer

Hi Tomas,
I have the rudder servo in Ch4 port, I am only wanting to use the Rud port for switching of the CDI via an opto isolated PWM operated switch, I am not using this channel for anything else.
Thanks,
Steve E

OK, we will try to prepare the firmware now. It might be ready today.

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Spirit System developer

Thanks Tomas and the team, I appreciate your help.
Steve E