how to change controls on Spektrum DX6i?

[JensR]

Hi Footprint!

Good to read from you!
I haven't managed more with my Arduino radio than before.
http://www.youtube.com/watch?v=_Cm3TxekJO4
It works quite wonderfully, but the idea of writing my own menu system is a bit intimidating...
Maybe I'll do everything in Arduino code, but this less flexible in the testing phase.
It seems that you do this? Are you happy with it?
Plus I need to get the machine running - the current control is nice enough, so the new one is not my priority.
I have not yet learned to work with electronic _components_ like you have. :-/
Hence I wiggle my way around that gap

Regarding your servo mount: because the axes are not parallel, you get a kinematic error and possibly binding in the servohorn.
/Captain Hindsight over


Anyway, for the SPDT, you could use something like:
http://defconbots.org/defcon14/design_gun.php
http://www.ntxbg.org/pgOnTheWays/pgRadioBasics.htm
(two SPST non-latching switches)

You could use a multi-pole rotary switch:
http://www.crashed.net/~nebulous/keg/index.html

Rotating the switch?
http://www.vac-u-boat.com/FireBoat.htm

Wicked way to use a stripboard for the switch
http://www.rcgroups.com/forums/attac...mentid=3955114

If one switch isn't enough:
http://www.rcgroups.com/forums/attac...mentid=3954038

Taken from here:
http://www.rcgroups.com/forums/showthread.php?t=1426075

Another way of using two SPST:
http://www.wopba.com/controls.htm
Interesting here the warning:
""""
Do Not mount a switch to a servo
Done it and fried the servo.
When contact is made it sends a pulse that will knock out the electronics in the servo.
"""
What do we make of this?
I can't imagine this being a problem - I have plugged in servos while the receiver was powered up, without a problem.

While I find the above pretty simple, your solution would probably be my preference.
If I understood it
Whereto is RCa connected?
TP102 is a transistor?
NPN?
Should that be TIP102?
Does this work with ~1A current draw per servo?
I guess it does:
http://www.futurlec.com/Transistors/TIP102.shtml
8A?

Would using a transistor create a problem because the switching and switched circuit are then not galvanically isolated?

7404 is an inverter?
555 a timer (I knew that one!)
7408 are AND gates (I remember the shape)

So, the RCa somehow sets a value for the value that the upper AND gate compares to the receiver signal? But these can only compare 1s and 0s? So it must be a pulse-width thing? Based on the 20ms pulse of radios, and the ~1500µs servo neutral?

The inverter means that the lower AND gate will always have the other value than the upper? That ensures that only one of the transistors will be active at any moment in time. (Neglecting switching speed?)
I think some distance between switching points is needed.
You cannot have 1501µs mean channel A and 1500µs mean channel B.
Does your circuit do that? If so, how?

I guess you see why _I_ think the switch is easier

Cheers
Jens

[footprint]

Originally Posted by JensR

It seems that you do this? Are you happy with it?

Yes and no, it requires alot more planning on every step eg thinking 5 steps ahead on everything so you dont box yourself in and have to redesign.
I look it as poor mans PLC & SCADA the end plan is i should be able to monitor everything, pump pressure, temps, do trending ect and rather then mixing have set points..but im along way from there...budgets

Originally Posted by JensR

Hence I wiggle my way around that gap

Nothing wrong with that as we can see here too much knowledge is a bad thing sometimes, over complicating things just means more to go wrong. And minor mistakes in the maths that cause everything to smell like fudge.

Originally Posted by JensR

Regarding your servo mount: because the axes are not parallel, you get a kinematic error and possibly binding in the servohorn.

The valve is usually flush with the plate and secured via the 2 points at the bottom, its all in pieces while i work on the pump. The real issue is the mounting points being so low the leverage causes it to wiggle abit. One issue with your servo to switch suggestion is programming in the end limits so your not trying to drive it past the throw limits, obviously setting the horn at the right length will help but then there is the issue of leverage with microservo's vs switching loads on miniswitches.

Originally Posted by JensR

Interesting here the warning:
[I]Do Not mount a switch to a servo Done it and fried the servo.
When contact is made it sends a pulse that will knock out the electronics in the servo.

Yes that is an interesting point, I think he is referring to RFI from switching hi current loads, similar to not mounting the Rx close to the motors.

Originally Posted by JensR

Whereto is RCa connected?
TP102 is a transistor?
NPN?
Should that be TIP102?

Yes there were also several mistakes in my sch (Snr Management in my ear and the late night)
RCa is the Resistance X Capacitive circuit to set the pwm for the 555
it should have been (33x10-9 x 30.3) t= R x C
and yes TIP but TIP107, im suggesting this as it has darlington diodes built in, preventing flyback ect. and yes up to 8A and they cheap,

Yes as presented your pretty much spot on with your understanding but thats where i made a mistake, gate B should be connected to the Rx (not Tx) active not the Signal channel, meaning if the signal is ~1µs gate A is closed if > ~1µs (not A & Rx) B is closed. Im assuming a vari pot for the 100ohm in the RC to allow for adjustment but if your using the "gear" channel its either 1 or 2µs (well on my DX7 it is anyway from memory)

The sch also omits most all the resistors, PF correction/coupling and protection as mentioned id do something quick and dirty so were all on the same page, as you can see we have at least 3 different ways, That said the simplest easiest as fhhhstix presents is using the model memory and it dont get much easier then that. As i said over complicating things Thats my wheelhouse. That said if your building beacons, flashers ect your going to have spare gates, heres a use for them.

Your Ardunio is looking good, keep at it, having seen your previous controller cant wait to see it all finished.