12CH 3-way PPM mixer - Page 8 - RC Groups
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Aug 02, 2011, 08:50 PM
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fmkit's Avatar
Luke, it's almost impossible to corrupt eeprom, in 10 years I've never seen corrupted flash Cypress chip.
I need to check button overwriting last channel PPM B, looks like small bug easy to fix - how many channels have you programmed to mix ?

Input PPM has to be atleast 3ch and there is no upper limit(but only 1st 12 can be mixed) I guess Flytron's headtracker has variable frame PPM so if active channels take 1st position nothing else output. I'll update newer mixer to input whatever PPM, send yours to reprogram also to add constant frame rate mode.
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Aug 02, 2011, 09:08 PM
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LukeZ's Avatar
Ok, I did not know about 3 channel minimum for the inputs, that explains what I have seen. You are right about Flytron DT-3K, I have checked on scope and if active channels come first then it only outputs the 2 channels, nothing else. Glad to hear you can reprogram.

As for the button I have tried it from 3-6 channels input on Port A (Port B I have kept at 2-3 in). The button behavior I observed is consistent regardless of how many channels.

If you don't mind I will just buy new mixer from you rather than wait to send this one back... I will send you PayPal.

I will send you a PM about details - but I won't need constant frame rate as I am not using TLRS and I agree, faster is better for my purposes.

It would be nice if button function could be at least two position (toggle between on/off) instead of momentary.


Luke
Oct 25, 2011, 07:22 AM
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fmkit's Avatar
Luke and Joachim V., I shipped newest mixers.
Programmed the same way (see post 97).
Button overwriting last B channel bug fixed
3 ch. input PPM limit removed (connect 2ch. headtracker while 1st channels active OK)
Added series resistors to inputs and output - connect into hi-voltage RF module direct.
Oct 25, 2011, 01:09 PM
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LukeZ's Avatar
Wow Peter, that looks very nice! Much improved, and it will be much easier to wire up too.

I look forward to testing it out, and I'll post here when I do. Thanks for keeping on this project!

Luke
Nov 20, 2011, 07:45 PM
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LukeZ's Avatar
Peter,

My mixer arrived about a week ago and it works perfectly. I have it installed in my JR9303 and I am using it with a Flytron DT-3K set to output 2 channels into input B of the Mixer. The Mixer adds the two channels to my radio stream just as it should. I also tested the pot and switch and everything works fine.

Thanks for keeping up with this project and being willing to make modifications for us. I think you have an excellent product now, one that does not exist anywhere else.


Luke
Dec 05, 2011, 11:09 AM
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fmkit's Avatar
Joachim V,. email sent to you bounced so I'll respond here:

the mixer outputs constant sinc
12ch PPM with sinc of 4ms needs frame of 12x2ms+4=28ms, at such long frame TLRS starts to glitch esp. if you trimmed some channels over 2ms and open few channels wide.
I've removed constant frame option to avoid glitches. The mixer works with everything (all sims, remotes...) but may glitch if used with TLRS that has that wanting constant frame. I've never heard of other system needing constant frame rate.

TLRS needs better firmware/update to accept normal (constant sinc) PPM . Think of tons of other equipment such as copter flight controllers, Any other UHF LRS. Why would I adopt ppm mixer to piece of equipment that has firmware defect ?
Dec 18, 2011, 10:38 PM
Registered User
Hi Peter,

Jochen bought a second mixer for me and I have the same issue.
Yes, the TLRS is not able to handle jitter, but there are no plans to change this. From this point of view, an extension of ppm channels requre on of the following options:
-throw away the TLRS devices and buy something else.
-throw away the futaba transmitter and buy a 12ch const frame transmitter.
-or find a solution to extend some PPM channels with const framing.

The first two optins will require several hundred dollar, so i would really appreciate if you could implement a constant framing. Even a 30ms framing will be ok. We need to add 2-3 channels at a 8 channel signal.

We have very good experience with TLRS, so I would rather think about changing the transmitter if there will be no mixer solution possible.

What constant timing does your previous version support? Maybe this version will be also ok for our demands.

Best regards
Jochen and Thomas



Quote:
Originally Posted by fmkit;
Joachim V,. email sent to you bounced so I'll respond here:

the mixer outputs constant sinc
12ch PPM with sinc of 4ms needs frame of 12x2ms+4=28ms, at such long frame TLRS starts to glitch esp. if you trimmed some channels over 2ms and open few channels wide.
I've removed constant frame option to avoid glitches. The mixer works with everything (all sims, remotes...) but may glitch if used with TLRS that has that wanting constant frame. I've never heard of other system needing constant frame rate.

TLRS needs better firmware/update to accept normal (constant sinc) PPM . Think of tons of other equipment such as copter flight controllers, Any other UHF LRS. Why would I adopt ppm mixer to piece of equipment that has firmware defect ?
Dec 26, 2011, 03:28 PM
What goes up...
Krylon's Avatar
Would this unit be capable of automatically overwriting empty channels in a PPM signal, or would it have to be programmed for the numbers of channels each time?

For example PPM A inputs 12 channels, and PPM B inputs 9...
Could this overwrite empty channels in signal A with the ones from B to still give a 12 channel output?
Last edited by Krylon; Dec 26, 2011 at 03:29 PM. Reason: speling and tpying are my strong points today
Dec 26, 2011, 04:57 PM
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fmkit's Avatar
Quote:
Originally Posted by Krylon
Would this unit be capable of automatically overwriting empty channels in a PPM signal, or would it have to be programmed for the numbers of channels each time?

For example PPM A inputs 12 channels, and PPM B inputs 9...
Could this overwrite empty channels in signal A with the ones from B to still give a 12 channel output?
sure, you can limit A input channels to first 2-12 then attach some channels from B input (also set limit 2-12) also add 2 channnels generated by the mixer (pot/button) + store each input failsaves, with FS PPM sum is of constant number, you can plug/unplug inputs hot and output will be pre-defined. Topic says 12ch output but new w/ latest FW you can output up to 24ch PPM

Fpv_Thomas: some time ago I was making constant frame rate output but TLRS would still glitch sometime even if PPM looks perfect on scope so I decided to remove constant rate so people won't try the mixer w/ TLRS and won't ask me questions that I can't answer. The mixer works with any other system ! I don't plan to make any changes and busy finishing up my own UHF LRS that is very flexible and can fit anyone, has user defined channels output, transmit 24 channels if you wish. And 5times faster than any other system.
Jan 06, 2012, 09:57 PM
Registered User

My issue is almost solved now


Hi Peter,

I belive key is, to keep an absolut exact frame-timing with using the TLRS. I have now almost finished my own PIC-Controller software for this demands because I couldn't find some alternative ready solution.

My project allows me now to simply add 3 analog channels on my existing Futaba FF9 with 8 channel PPM output.

Additionaly, my selected PIC controller type supports up to 12 analog ports which will avoids any additional HW - apart from poti's or switches for the channel inputs. I will use this controller also to upgrade all my legacy RC- transmitters by just replacing the existing encoder electronic by simply this single chip.

My solution allows every constant frame-timing configurable in 100ns steps. Also the PPM decoder and encoder resoluton is with 100ns far beyond my demands.

I am waiting now for good weather-conditions to test the solution in real life. The lab tests has worked fine (In fact, I have also detected some silghtly jitter ~100-200ns in mid term at the Futaba PPM output signal which was so far no problem for the TLRS too)

Let's see if this own Controller solution works also in long term well with TLRS together.

best regards
thomas
Jan 07, 2012, 06:45 AM
Registered User
Hugeone's Avatar
Quote:
I've never heard of other system needing constant frame rate.
-Dragonlink
-Chainlink
-Rangelink

They all need constant frame.
Jan 07, 2012, 11:09 AM
fast
fmkit's Avatar
Quote:
Originally Posted by Hugeone
-Dragonlink
-Chainlink
-Rangelink

They all need constant frame.
CrashMeUp using wireless nunchuck (constant sync rate) w/ his DragonLink,
Chainlink/Rangelink by Sid, did he mention constant frame rate ?
I looked at OLRS and ROLRS code - they take whatever PPM, the mixer doesn't care if inputs are of constant sync or frame. TLRS seem the only one needing special PPM.

Since summer I'm testing/using new LRS that takes whatever PPM and can transmit up to 24channels very fast and multiple repeaters can provide good range without boosters and IMU is built-in. Those I fly with switched from TLRS to new system, there is not one left to try different firmware mixer.
Jan 07, 2012, 11:46 AM
Registered User
Hugeone's Avatar
Sid confirm constant frame, he actually suggest my workaround for the 12Z:
https://www.rcgroups.com/forums/show...&postcount=827

Dragonlink also need constant frame:
https://www.rcgroups.com/forums/show...postcount=4896

-Hugo
Feb 19, 2012, 10:06 PM
Registered User

Instructions?


I have just received my mixer (the new version as pictured earlier on this page). I am having trouble finding instructions on hookup and programming - everything I have found is a short "what's new" type of thing. Does anyone have a link to where I can find some proper instructions to hook this thing up and program it?

I need to add 2 x 3-position switches (on channel 7 & 8) to my existing 6-channel stream.

Many thanks,

--Nick
Feb 19, 2012, 10:50 PM
Registered User
LukeZ's Avatar
Nick, I believe these are the latest instructions. There isn't an explicit option for adding 3-position switches that I am aware of, unless Peter added something new. You can however add two pots (analog) channels. I suppose if you wired up some resistors to a three position switch to emulate a pot it would work (try two 2.5k resistors per switch).

Luke


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