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Signal splitter

PostPosted: Sun Mar 27, 2011 10:01 pm
by Aviator
Hi guys. I hope someone can help me out.

What I am trying to do is to hinge ailerons with no gap. I have done it on few of my foam planes and it works good... but with a small down draw - it has a free play in its neutral position.
It works like this:

To eliminate the free play I need to have a signal split between two servos that while one servo is moving the aileron down, the other servo remains in neutral. Then the first servo will remain in neutral while the second servo is moving the surface up. I hope it makes sense.

streamlinedwing.jpg (17.87 KiB) Viewed 5994 times

So far I tried using logic gates to create a 1.5ms pulse out of the incoming control signal and then direct the control signal to one servo or the other according to its width, while sending 1.5 ms (neutral) to the opposite servo. It doesn't work very well.

I know there are many ways to deal with this problem, so I am looking for a reliable, efficient, more less simple... well you know what I mean.

Any ideas?

Re: Signal splitter

PostPosted: Mon Mar 28, 2011 7:21 am
by pwy
Hi Aviator,

Logic gates don't work very well, better to use a small microcontroller like a PIC for such things.
My personal version would be to use two channels and some creative mixing in the radio. Simple if you have enough free channels available.

The definitely easiest solution is to be less picky and accept the small gap you get with a standard set up ;-)

Hope you find a way to do it

Re: Signal splitter

PostPosted: Mon Mar 28, 2011 3:14 pm
by Flash1940
In flaperon should be able to do this with travel adjust/(endpoint adjust)....set travel adj. on aileron to 100% - 0% and the other aileron channel.....Aux-2 usually to the same thing.....100% - 0%. This will give you two servos that push or pull.....but not both as do normal ailerons. Use a "Y" connector to establish the other wing set. That's how I would try it.....maybe someone else here may have another idea....


Re: Signal splitter

PostPosted: Mon Mar 28, 2011 4:45 pm
by Aviator
Thank you guys! Thank you Flash1940, you are a genius in my books forever! Why didn't I think of it myself?? GRR!!! I spent all this time soldering little tiny SMT chips... (and this morning, just before I read this I finally got it to work!) and now you ruined everything! LOL

Thank you so much!

Re: Signal splitter

PostPosted: Tue Mar 29, 2011 2:24 pm
by Flash1940
Here's a good thing to always remember..... I even teach this concept to my students when we explore "trouble shooting".


Re: Signal splitter

PostPosted: Tue Mar 29, 2011 7:22 pm
by Aviator
Flash1940 wrote:Here's a good thing to always remember.....

Its a good concept, some people call it KIS - Keep It Simple. In order for that principle to work you need to have at least two solutions with one of them being more simple (and just as effective if not more effective) than the other one. So thanks to you I got the most simple and elegant solution to my problem and I am keeping it. And I am still kicking myself for not thinking of it myself :)

I even teach this concept to my students when we explore "trouble shooting".


Something like - is the switch "ON"? is your power cord plugged in?... is there power in the outlet where the power cord is plugged in?.. is there power entering your system?
After that you need to be very familiar with the system you are working on and its components - what do they each do in the system and identify the one that is not performing. Then you can go deeper.

Trouble shooting an intermittent is one of the difficult ones, because it usually works fine while you are messing with it... :?

A faulty equipment has its usual set of “weak spots” and if you go through a good number of them you become more efficient in identifying the problem.

So.. yeah.. still kicking myself. LOL

Re: Signal splitter

PostPosted: Tue Apr 05, 2011 8:28 pm
by Flash1940
Don't be "kicking" yourself......remember...."self" is your best GOOD to yourself.....There is only ONE "self".