Dual Rate question

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jmendoza
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Joined: 18 Feb 2018, 23:07

Dual Rate question

Post by jmendoza » 10 Mar 2020, 00:47

Phil,
Can rate be added to the DigiSpark 3 or 4Ch?
Could a pot be used as a rheostat across the control pot along with isolating resistors to plus and minus supply in series with each end of the control pot?

I have a very small 3 channel Tx and need more room for the 2.4GHz module so going from a DIYMore Strong to the DigiSpark will allow me the extra room needed. I could mount the rate pots on a tiny piece of vero.


Thanks,
Jay

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Phil_G
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Re: Dual Rate question

Post by Phil_G » 10 Mar 2020, 09:37

Hi Jay, I did reply on RCG:
https://www.rcgroups.com/forums/showthr ... st43934585
If its an old set, the problem is that the 'end' resistors are not equal because the stick pots are never central at neutral stick on a half-shot encoder. The resistors would need to be selected on test to give the rates effect you need whilst maintaining neutral. Its easier to use presets, say 5k or so. The idea is much easier with modern sets where the stick pots are exactly midway at neutral stick but sadly that is almost never the case with a half-shot encoder. Remember that rates affect any trim offset so to use them frequently you need to physically trim the model to fly at neutral trim, or rates will affect neutral. I just move the stick less :D
Cheers
Phil


switched_fixed_rates_PhilG.jpg


Tiny trimpots can be mounted on the switch tags.

jmendoza
Posts: 115
Joined: 18 Feb 2018, 23:07

Re: Dual Rate question

Post by jmendoza » 10 Mar 2020, 19:07

Hey Phil,
would this work for the Digispark? I always center the stick pots when doing conversions.
Thanks, Jay
rates for digispark.JPG

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Phil_G
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Re: Dual Rate question

Post by Phil_G » 10 Mar 2020, 20:12

Yes Jay thats pretty much the Radiolink diagram I posted for you on RCG :D
https://www.rcgroups.com/forums/showthr ... st43934585
You would need to centre the sticks exactly though.

We're bang-bang enthusiasts - rates ????? you could always move the stick less :lol: :lol: :lol:

jmendoza
Posts: 115
Joined: 18 Feb 2018, 23:07

Re: Dual Rate question

Post by jmendoza » 10 Mar 2020, 21:16

Thanks Phil,

I thought that "washing out" the stick pot with a resistance in parallel to it would do the trick but just wanted to be sure. I'll set it up for equal voltage readings from the wiper to each outer lug for exact centering and give it t try. I only need elevator rate as the rudder throw is fine. Obviously I will have to set the rate pot to max resistance when doing the calibration.

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iflylilplanes
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Re: Dual Rate question

Post by iflylilplanes » 10 Mar 2020, 23:05

When I learnt to fly RC, my first radio a Futaba FP-5DN didn't have dual rates, expo or even servo reversing, as Phil said move your fingers less.

I use a Taranis X9D+ today with all the bells and whistles, still don't use dual rates, do use expo a little if I remember to set it, I find if I have too many functions setup on switches I end up forgetting to use them.
Cheers,

Dave

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