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Old Mar 13, 2012, 03:55 AM
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Originally Posted by Mikarro View Post
I found this thread because I was just reading this one http://www.rcgroups.com/forums/showthread.php?t=1611869
the next time hope you open a thread like this in the correct section because I did know nothing about a new Devo 10
You are quite right, but as Livonia Bob wrote, if it wasn't in the micro's forum, most of the Walkera users would miss it.
The radio forum is 99% Spectrum/Futaba/JR related, there nobody cares about Walkera. That kind of threads will sink quickly...
That is because Walkera radios are not compatible with others, but only good for Walkera helis and receivers. Since Walkera almost only produces micro helis, it seemed logical to post it in that forum. The new quads might change that...
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Old Mar 13, 2012, 04:46 AM
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Now it is available in english:
http://www.walkera.com/en1/devo10/devo_10_index.html
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Old Mar 13, 2012, 03:00 PM
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Originally Posted by i812 View Post
IMO, there shouldn't be a need for the TX to always blindly send 2 different "handshakes" to a RX, one at a time, in order initialize both types of RX's. Why not ask the User during the TX's Model Entry menu which type of RX that Model has?

I doubt there is any different "handshaking" protocols between the 2801 and Devo TX and RX. I'm new at this stuff, but suspect the TX & RX communication is still 100% the same between the two. What I believe is different between the 2801 and Devo TX/RX is:
  • a 2801 TX only transmits to RX, and its "field" RX only receives info from TX (it's a one way communication path)

  • a Devo TX must ALSO receive telemetry info from the field; therefore, the TX RF module must have receive as well as transmit capability, and likewise the field module(s) must have transmit as well as receive capability.

I'm guessing with either 2801 or Devo, the info being transmitted from the TX to the RX is 100% the same: "X" channels (pulses) worth of PPM (pulsewidth) info being transmitted. Only thing needing to be different is info being received by TX, and maybe it is being received exactly the same way: as an additional "Y" channels of PPM info? If so, there would be no need for any additional handshaking/protocol - just keep on doing the same thing on the same frequencies. For all practical purposes, the only difference between 2801 and Devo might be that the Devo has additional 4 Voltage, Temp, RPM, and GPS info "channels" being sent to TX.
The WK2801 is FHSS and the Devo radios are DSSS (says that the Devo 10 is DSSS right on Walkera's page for it)
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Old Mar 13, 2012, 04:21 PM
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Oh!

Thanks for pointing that out.

I'll stop hoping for backward compatibility.
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Old Mar 13, 2012, 06:41 PM
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Originally Posted by i812 View Post
I'm new at the RC protocol, but from what I've recently read, the only difference between 2401, 2601, and 2801 is the number of pulses being transmitted, where essentially the width of the pulse indicates that particular channel's stick position.

A 2801 TX has ALL the capability of talking to all 3 types of RX's. To the best of my newbie knowledge, during Model Setup when we program our 2801 which "mode" to transmit in, all that happens is the "extra" pulses for the channels (stick/switch positions) that won't be transmitted are simply "dropped" from the serially transmitted pulse train. The stick/switch positions are re-measured, the pulse train is updated and re-transmitted 20? times per second.

For instance every 20? seconds, this many pulses are transmitted:

8 channel mode = 8 pulses, with each pulse having a width that corresponds to a channel's "stick" value between MAX and MIN. From what I remember the pulsewidth is a "universal" Servo standard: 1.5 msec +/- 0.5 msec, where 1.5 msec = mid "stick"

6 channel mode = 6 pulses

4 channel mode = 4 pulses

The RX circuitry simply demodulates the pulse train off the RF (microwave) carrier, serially "strips" the pulses off the "train", and sequentially switches the pulsewidths to its appropriate "channel".

Apparently before Devo, if a 4 channel RX received 8 pulses in a "serial" train, it would get confused, so the TX had to be programmed not to transmit extra unwanted/un-used pulses.

Maybe the new Devo RX's have better circuitry, are able to disregard the extra unwanted pulses, and therefore don't need to have the TX pre-programmed to operate in a specific mode?

Someone told me (guessed?) the only reason Devo TX isn't backward compatible is because it waits to receive valid "handshaking" data to be transmitted from the telemetry unit in the field, before the TX completes the initialization routine with the RX in the field. If this is true, and if it was possible, a User could use the Model Setup to pre-program the TX to operate in a certain "mode" (2401, 2601, 2801 just like the old days), and if in that mode, the TX wouldn't require Telemetry validation/handshaking to sucessfully complete initialization, and wouldn't transmit extra unwanted pulses.

Once again, I'm sure this "chat" is OT, and doesn't belong here in this thread. It is probably too basic and "intro" TX stuff to be posted in the "hacking" thread, and I probably won't get any knowledgeable responses posting it anywhere else, so I'll keep on "threading" along in this thread since it currently has "hacker" eyes looking at it.

I think I've reached a plateau where there's not much more mechanical stuff for me to learn about RC Helis, so I'm at a point in my RC training where I'm trying to get a deeper understanding on how the electronics works.

From what I understand, one of the biggest differences between one manufacturer's RC transmitting protocol and another's is whether the pulse trains are transmitted upside down or not, and the ordering of the pulses. Regardless of which protocol is used, the pulsewidths are all universally understood to represent the same value.
interesting explanation and even knowing that the WK2801 is FHSS and the Devo radios are DSSS - gives an idea how things are done - however its too simplified to explain the exact system used - with 2801 in 2801 mode you can set up fixed ID so you would need a carrier to tell the Rx it was sending fixed ID apart from the usual 8 channel -then after fixed ID binding you would need a fixed Id key in the signal to tell the Rx that signal was for it.

I have every confidence given time hackers will unravel just how things are done MatCat has already made a good start with the new screen he is writing for himself

Regards David
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Old Mar 14, 2012, 02:38 AM
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Originally Posted by i812 View Post
Oh!

Thanks for pointing that out.

I'll stop hoping for backward compatibility.
They both use the same RF chip so there's no reason the Devo radios couldn't speak to WK2801 receivers except that Walkera doesn't want them to.
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Old Mar 14, 2012, 03:11 AM
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Originally Posted by i812 View Post
I'm new at the RC protocol, but from what I've recently read, the only difference between 2401, 2601, and 2801 is the number of pulses being transmitted, where essentially the width of the pulse indicates that particular channel's stick position.

A 2801 TX has ALL the capability of talking to all 3 types of RX's. To the best of my newbie knowledge, during Model Setup when we program our 2801 which "mode" to transmit in, all that happens is the "extra" pulses for the channels (stick/switch positions) that won't be transmitted are simply "dropped" from the serially transmitted pulse train. The stick/switch positions are re-measured, the pulse train is updated and re-transmitted 20? times per second.

For instance every 20? seconds, this many pulses are transmitted:

8 channel mode = 8 pulses, with each pulse having a width that corresponds to a channel's "stick" value between MAX and MIN. From what I remember the pulsewidth is a "universal" Servo standard: 1.5 msec +/- 0.5 msec, where 1.5 msec = mid "stick"

6 channel mode = 6 pulses

4 channel mode = 4 pulses

The RX circuitry simply demodulates the pulse train off the RF (microwave) carrier, serially "strips" the pulses off the "train", and sequentially switches the pulsewidths to its appropriate "channel".

Apparently before Devo, if a 4 channel RX received 8 pulses in a "serial" train, it would get confused, so the TX had to be programmed not to transmit extra unwanted/un-used pulses.

Maybe the new Devo RX's have better circuitry, are able to disregard the extra unwanted pulses, and therefore don't need to have the TX pre-programmed to operate in a specific mode?

Someone told me (guessed?) the only reason Devo TX isn't backward compatible is because it waits to receive valid "handshaking" data to be transmitted from the telemetry unit in the field, before the TX completes the initialization routine with the RX in the field. If this is true, and if it was possible, a User could use the Model Setup to pre-program the TX to operate in a certain "mode" (2401, 2601, 2801 just like the old days), and if in that mode, the TX wouldn't require Telemetry validation/handshaking to sucessfully complete initialization, and wouldn't transmit extra unwanted pulses.

Once again, I'm sure this "chat" is OT, and doesn't belong here in this thread. It is probably too basic and "intro" TX stuff to be posted in the "hacking" thread, and I probably won't get any knowledgeable responses posting it anywhere else, so I'll keep on "threading" along in this thread since it currently has "hacker" eyes looking at it.

I think I've reached a plateau where there's not much more mechanical stuff for me to learn about RC Helis, so I'm at a point in my RC training where I'm trying to get a deeper understanding on how the electronics works.

From what I understand, one of the biggest differences between one manufacturer's RC transmitting protocol and another's is whether the pulse trains are transmitted upside down or not, and the ordering of the pulses. Regardless of which protocol is used, the pulsewidths are all universally understood to represent the same value.
It might be quite far from truth...
Here are the findigs of rcH4x0r about the simplest 4ch Walkera protocol (24xx):
http://rch4x0r.com/walkera_4_ch_packet.html
http://rch4x0r.com/walkera_freq_hopping.html
Have a good read!
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Old Mar 14, 2012, 02:09 PM
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Wow, packet "protocols" galore!

Totally different from the PPM stuff I posted earlier.

Thanks very much for posting the links. Very interesting read. I learned alot today!!!

I hope to find more info about rcH4x0r's OWRX (Open Source Walkera 4Channel, 2.4GHz Receiver). If I can find more info, I may become a rcH4x0r "groupie". I imagine it'll be just a matter of time before he'll be able to do some very interesting on-board things with the Telemetry Data.

The more I get exposed to it, the more I think I need to learn how to "breadboard" a Multi Rotor Copter. IMO, understanding the "brains" behind RC stuff, and being able to make changes as desired is more enjoyable than flying.

Thanks for sharing! I'll try to eat it all up!!
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Old Mar 14, 2012, 03:54 PM
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Originally Posted by livonia bob View Post
Will you be carrying the Devo 10 with the Lady Bird as a package?? Or will we have to order them separably?
The LadyBird will be available as a RTF with Devo 10.

Jonathan9113
www.WowHobbies.com
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Old Mar 14, 2012, 04:03 PM
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The most useful function of the Devo 10 IMO is the low voltage vibration alarm. You can set the voltage to trigger the alarm (under external alarm setting in the menu) and it will either vibrate or buzz when the voltage is reached. You can do the same for temperature but I think the voltage is the most useful one. For the T-Rex 250, 450, 600, the vibration sent to your palm is a cretical feature as it gets quite noisy and often the buzzing is not heard. This voltage feeback through telemetry to trigger the alarm revolutionalizes the traditional timer function in which we are still constantly worrying about low battery.

Jonathan9113
www.WowHobbies.com
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Old Mar 14, 2012, 08:24 PM
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Originally Posted by wowhobbies View Post
The most useful function of the Devo 10 IMO is the low voltage vibration alarm. You can set the voltage to trigger the alarm (under external alarm setting in the menu) and it will either vibrate or buzz when the voltage is reached. You can do the same for temperature but I think the voltage is the most useful one. For the T-Rex 250, 450, 600, the vibration sent to your palm is a cretical feature as it gets quite noisy and often the buzzing is not heard. This voltage feeback through telemetry to trigger the alarm revolutionalizes the traditional timer function in which we are still constantly worrying about low battery.

Jonathan9113
www.WowHobbies.com
This is very important to me,, I have even tried to do this myself but didn't have the knowledge to pull it off.. I can't hear in the range that most TX beep and have to stick a large kitchen timer on my TX's so I can see quickly how much time has passed..
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Old Mar 15, 2012, 01:45 PM
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Originally Posted by wowhobbies View Post
The LadyBird will be available as a RTF with Devo 10.

Jonathan9113
www.WowHobbies.com
How about Devo 10 with Walkera helicopters, Mini CP or V120D02S?
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Old Mar 16, 2012, 11:38 PM
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I just ordered one from wow on the pre-order. I hope I'm not disappointed.
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Old Mar 17, 2012, 06:50 AM
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I just ordered one from wow on the pre-order. I hope I'm not disappointed.
I hope you are happy with it.. I have one in my cart but can't force myself to push the buy button yet...
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Old Mar 17, 2012, 07:25 PM
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I called wow earlier this week & they said 3/23 is only an estimate. I think my 2801 pro is starting to go south. I hope I made a good choice.
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