Deviation for Devo F4?

Hi guys!!

Is it possible for a deviation version to be made for the F4 with working FPV? I read on RCGroups that the F12 one was being looked at, and was wondering if it was going to be "extended" as the thread was from a while ago.

Thanks!!

if you can send the picture of what are into the devo F4, maybe we can do something.
PB, are working on devo f7, and I did some changes, but PB and me have not to much time now, but maybe is ease to do the port.
send me a lot of picture chips that there are into the radio.

Hmm, just did a quick image search and came up with some internal photos (of sorts) in this rcgroups thread . Looks like it uses the same processor as the 7E, the STM32F103RBT6? And is that an 8S-type TX module? It's completely sans switches from the looks of it, so some serious hardware hacking could be in order if looking at using it in any remotely serious manner.

Hi guys!!

TBH with you, I can't say for sure everything yet because I don't actually have it in my hands... I got the transmitter cheap, but it's still in transit, probably arriving tomorrow of Thursday.

I got the transmitter because as I said, I found it cheap, and from what I was reading up it seemed to be a pretty interesting transmitter with the screen and everything which has a pretty good picture for the size, add that to the fact you can plug a monitor or some goggles in to it, it's a good thing to have in your inventory on a budget. The antennas are pretty limited, but there are already mods out there that increase range on both the 2.4ghz and the 5.8ghz. I originally planned it for using with some flying wings, which don't need much in the way of controls, but was thinking it was a shame it couldn't be used easily with simple quads because of a lack of a button to change the mode, leaving you stuck in acro, which is great for running around, but you don't always want it.

The transmitter does come with dual rates, but they are controlled from the up/down buttons on the menu which is a bit uncomfortable in flight, and I was going to just extend those buttons to the top with a couple of momentary trainer switches (one for up, one for down). But from the photos I've seen, it looked like as you said, the inners of a 7E on many things, and I thought if it could be Deviated, and have some switches added for channels, and still maintain the video capability, then it could become a nice go to transmitter for people with miniquads on a budget, as it has 15 model memories, has D/R and Expos, throttle curves, the gimbals are nice, good image from the screen, video out, uses the Fatshark band for 5.8 so it's really compatible on that end...

If a Deviation version is possible, it might be possible to add in proper D/R or T/R on a switch, mixes, and maybe even gimbal control for camera like pan and tilt...

Once I have the transmitter in my hands and I can open it I'll confirm the chips it uses. I'll try to add photos, but my camera is just an old compact, so macro isn't it's strongest point.

I hope that the F4 has the same video screen like f7, but must be very important to know what pins are connected to the mcu, and what type of memory has. maybe the memory is less than the devo f7. devo f7 has a little memory, PB did a special fly system for this radio, but in my port I'm using another flash memory with more space, because the original has less memory like 7E. and now there are a lot of problem with the space into 7e radio.
But I think that is not to hard to try to put another firmware into this tx. but we need all of the information.
maybe you must search for the original firmware, because the first version cannot be used to fly.

As far as I know it uses the same screen as the F7, in fact, the mould for the case is that of the F7 too, as only the colour changes, but inside it has the same switch resorts as for the F7.

Memory and all that stuff I have no idea how much it has, nor do i know how to look. When it comes, I'll try and take photos as good as I can of both sides of the board, and if you need to know a particular chip model number that can't be seen in the photos, then I can have a look at it and write it down. One thing that might indicate the amount of memory it has is that it only has memory for 15 models, where as the 7E has 30. Granted that the F4 also has video stuff to contend with that the 7E doesn't, but even so, that is something that would stay even if a change of firmware is possible.

Obviously, this transmitter is a little limited, maybe even if there were only 6 accessable channels because of limited memory, and compatibility with the protocols the resident RF chip is compatible with, without the possibility of adding additional modules, it's still a huge leap. I mean,with a couple more channels and DSMX compatibility alone would give it so much as for multirotors, as it would be able to control flight modes and other things, as well as have PPM compatible receivers available for it. I know it will never be an F7, it's not supposed to, and I wouldn't expect it to, but if there is a possibility of squeezing a little more out of it, I think it could become an interesting transmitter for those initiating in FPV and wanting the Deviation flexibility. Make it like the "7E of the "F" range", not as good as the others, but still a great transmitter.

When it arrives I'll let you know, and I'll see if my old Nikon can take any useful photos (it's only a Coolpix S2500).

One thing I though I should add, as it may be an indication of something... I was looking into compatibility with the Walkera QR W100. The transmitter was more designed for the Ladybird with the 5.8 camera, but when the W100 came out, they gave it compatibility to use the 5.8 camera from the Ladybird on it instead of the standard WiFi one, to use with the F series transmitters, including the F4. This quad can bind basically with any Devo, but it has a rates system in the flight control board. It has a red mode (red LED in the canopy) which is 6 axis stabilization, and then a blue mode (blue LED in the canopy) to show 3 axis stabilization. On the Devo 4, you change modes with the rates button, and this would lead me to believe that it has a 5th channel to do this (I could be wrong, I'm just going by simple logic). Someone was asking on RCGroups how to change mode with the F4 as it doesn't have this rates button.

It turns out to be a bit of a ta-ta to change modes, but you can. Evidently, you turn on the quad, then the transmitter, let them bind, then turn the quad off, and with the transmitter still on put the throttle to maximum, then turn the quad back on, and it will rebind and change mode. To change back you do the same again.

Now, this would lead me to understand that either the F4 can access this rates channel, or that the W100 has built into the firmware to accept this throttle combination on the throttle channel. If it is the latter, then it's just using 4 channels, but if it's the prior, and they had to program this sequence into the chip, but the ability to process it and transmit on a 5th channel are both there, which with a little remapping might mean an accessible channel...

I just though I'd mention that, as it might be useful.

Well, my F4 arrived today, and the first thing I did (after turning it on to make sure it worked) was null the year's guarantee on it by opening it!! I hope it works, as I don't have a Devo receiver yet to bind it with to verify that it indeed works... so, there goes nothing!!

Anyway, I took a few photos inside, it took a few tries to get the photos in a quality that was good enough to see anything, but I think I got it. I have kept them in their original format to try and keep as much detail as possible, so I've uploaded them to my photobucket account for you to see, the links are below

i151.photobucket.com/albums/s123/HororoK...2457_zpsxt4skccx.jpg
i151.photobucket.com/albums/s123/HororoK...2464_zpsmgkv3zcn.jpg
i151.photobucket.com/albums/s123/HororoK...2463_zps4dae7xye.jpg
i151.photobucket.com/albums/s123/HororoK...2462_zpsi0ztg9eo.jpg

I think you can see the components pretty well really. The upper board is connected to the lower board only by that 4 wire pigtail with the colours going as follows: Red: 5.5V, Black: GND, Yellow: AV2, White:PWM (although the solder point for the white is rather large and seems to be connecting with some other pad, but I can't see which).

The 2.4ghz module is clipped in using the 10 pin jumper connector on the bottom, similar to what you find on the nRF24 modules, rather than being soldered direct to the main board. There is one point of solder between the RF board and the main board, but it seems to be just a ground point which has to be unsoldered if you need to remove it. It is screwed into place on the top with the plastic part that is holding the antenna connector firmly in place.

Oh, one more thing, I'm not sure how the dual rates are supposed to work, because you program them in and that's it, but when you are flying, turns out that the L- button in the main page activates the throttle curve, asking if you want to "all servos hold". I don't know much about this, as I don't know anything about helis.

On the main screen the UP+ button controls the start and stop on the timer, and the DN- button resets the timer. The R+ button doesn't seem to change anything though, and I have a feeling this might be D/R toggle, but I can't tell for sure until I get the receiver and I can visually see the change on a servo.

On the screen, on the top you have the timer, followed by the model number, the letter A for Aeroplane or H for helicopter, and a number which I don't know yet what it is (I'll have to see in the instructions). On the right of the top of the screen is the battery voltage.

On the bottom of the screen are five zeros. The first shows percentage of throttle (from 0 to 100, not -100 to +100 like on the 7E), then the next zero is rudder trim, then throttle trim, followed by elevator trim, and the final zero for aileron trim (this on mode 2 of course).

The buttons have the same clear plastic ring around them of the F7, so I think I can probably add LEDs in there just like the F7 has, which should give it a little personality...

I can't see very well the flash memory. can you try to can a close picture on the flash memory and the other 2 chips there are close to the mcu?

OK, I'm not sure which ones you mean, so I just took down the numbers of the 3 that are around the main chip.

The bottom right one is slightly scratched at the beginning, making the first 2 figures hard to make out, so I might be wring on the first 2 of that chip

i151.photobucket.com/albums/s123/HororoK...tail_zpsiwuwtli9.jpg

I hope I got the right board hehehe

Same CPU as the 7eee and it looks like the same rf module as the 6/8/10/12, so that's all good.

Does it have user-upgradeable firmware? Is there a USB port you can use to flash it with an upgrade? Looks like there might be one be the chef module, but I can't be sure.

Yes, it has a USB port and is upgradable as usual via the Dfuse application

One sec... looking over the photos again, I noticed the same cluster of connectors next to the RF module that we use on the 7E to add modules...

With this in mind and what you just said mwm, are you saying this is basically a 7E with a built in FPV system, and no pesky range mod to have to do? Well, I don't know about you guys, but the possibility of it being even half deviated I find pretty exciting!!

Considering these transmitters can be found on Ebay even for about $80, it does make things interesting. It might not have the range of a groundstation or the comodity of goggles, but it's certainly a great for a cheap, "travelling light" FPV setup!!

Epitaph wrote: One sec... looking over the photos again, I noticed the same cluster of connectors next to the RF module that we use on the 7E to add modules...

That "cluster of connectors" is a standard debug connector for the STM micro controller used in all the Devo transmitters. It would be surprising if it weren't on the board somewhere. So you can't really draw any conclusions from it.

But "a 7e with a built in FPV system" doesn't sound like a good target for a deviation port. Adding support for a second radio and a video processing system to the already memory limited 7e doesn't sound like a good idea.

If it's like the other FPV transmitters, the display is much simpler, being a simple character graphics display (that's based on a quick look at the sources, so take it with a grain of salt). If so, that will offset the extra memory use for the FPV system. Whether or not it will be enough is an open question.

Isn't there any way to actually increase the memory, like by changing the memory chip or something?

Noob with a noob question here heheheh

But I still think that even if it were limited to even say 10 models, and limited functions and channels, like 6 channels only, it would still be pretty interesting...

Actually... is it possible that there is a graphics memory under that ribbon cable on the screen board? I mean, maybe the graphics part for the video processing has its own memory and it's not all being done by the main board one...

Epitaph wrote: Isn't there any way to actually increase the memory, like by changing the memory chip or something?

Yes, change the microcontroller. That's the big chip in the middle. Look for the thread on "the ultimate 7e" for information on that project.

But I still think that even if it were limited to even say 10 models, and limited functions and channels, like 6 channels only, it would still be pretty interesting...

Models use a different memory. There are three different memory types in the transmitters. One has the file system, holding model files, protocol code, icons, etc. AFAIK, not a problem so far. The other two hold code, one for protocol and the other everything else, and both are running into problems. That means we can't add features to some protocols, or to the transmitter in general. I believe that's why DSM telemetry is odd on the 7e, and I know it's why some of the test builds don't have 7e builds.

I see the dilemma... but there isn't a way to do a "lite" version then?