34 replies to this topic

[mrfliboy]

I have just picked up a 4channel Futaba radio which has a buddy cord plug also.

I'd like to figure out how to get 2 of the channels (1 gimball assembly) onto channels 5 and 6 in my Futaba 7C. Using my buddy cord. I believe similar to the manufactured HT. Or is a 6 channel donor radio needed?From there I'll be going mechanical for my Myvu glasses. Thanks for any and all suggestions.

Similar to http://rcexplorer.se...eda83de-75.html He's using Ch 4 and 5, I'm hoping to find 5 & 6. Feasible at all??

[Kilrah]

You'll need a 6CH donor radio indeed, or find a way to rewire one of the gimbals your 4CH radio to use CH 5-6 if possible.

What your 7C will do when enabling trainer on channels 5 and 6 is take the corresponding channels from the trainer port. So, the channel numbers need to match.

[mrfliboy]

Thanks so much for the info. I was thinking 6 channel needed.

[mrfliboy]

Well I found a cheap Hitec 6 channel with trainer port. Started the disassembly last nite and so far not bad. As I've removed components I check after every step too make sure all still works.


The amount of throws with the stock 5 and 6 channel turning knobs was say 90 degrees or so. Now I went and removed the knob pots and hooked up to the gimbal pots and my movement is less than 30 degrees. The turning knob pot was 10ohm and I believe the gimbal pots are 5ohm.

Is my next step to change to 10ohm pots on the gimbals or am I missing something here. Thanks for any and all help.

[Kilrah]

Those would be 10k ohm and 5k ohm. But (as transmitters and position measurements are usually made) changing the pot value might not change anything. The issue is simple, look at how much you rotate the CH5 and CH6 pots - usually around 270°. How much does the pot move in the gimbal? only about 90°...

Didn't actually think of that earlier, but indeed the transmitter might have circuitry (resistors) between the gimbal pots and the processor that doesn't exist on the CH5-6 inputs. You might want to check if you see something that could be replicated. Or, which is more likely, it's just software calibration, in which case you'd be out of luck...

Edited by Kilrah, 28 September 2009 - 07:09 AM.

[mrfliboy]

Thanks for the reply Kilrah,

I believe I saw where someone had adapted a gearing setup to the gimbals and pots, I believe I know why now. I'll check the mount of movement on the gimbal pots later today and compare. Thanks

[mrfliboy]

Here goes.... with the stock Channels 5 and 6 knobs i get around 90 deg of movement. With the gimbal setup down to 30 deg or so. With the gimbal pot removed, I'm back to 90 deg or so, so I could gear it but only to 90 deg. If I was to use a 10turn pot would that make a difference?? Thanks again.

[Mr.RC-Cam]

If I was to use a 10 turn pot would that make a difference??

A ten turn pot would make the problem ten times worse.

Time to see what can be hacked in the Tx. What Hitec Tx are you using? What is the FCC ID?

[mrfliboy]

Its a Hitec Focus 6

FCC ID IFH FOC456

Also I have no servo movement on either 5/6 unless a pot is hooked to both channels. When I hooked up the gimbals I removed all the trim tab stuff. I'm direct wiring to the gimbal pots.

The good news is I got my 5way splitter in today and all is fine with the ground station. 7' monitor, Myvu glasses, Sandisk recorder and MP5 player. All being powered from a 2200ma 3cell w/lipo monitor and only the DVR had to have a voltage regulator (20amp brushed esc with a heat sink)

Thanks

[Mr.RC-Cam]

Basic R/C Tx's from the 1990's era (like yours) are based on the NE5044 R/C encoder. The scaling for the stick pots is a simple electronic affair; usually three or four fixed resistors and occasionally an OPAmp will be involved. The best thing to do is to reverse engineer the channel for one of the sticks and then copy the components onto the new channel you want to use.

[mrfliboy]

Thanks for the info. I'll be giving it a shot tomorrow.

[mrfliboy]

By chance if I'm noty able to reverse engineer this, would this work??

http://www.nghobbies...SSV3 manual.pdf

[Mr.RC-Cam]

That product will double the existing servo throw. It installs on the Rx.

[mrfliboy]

Thanks again. I'm thinking just wiring it in between the pots and my donor TX board.

I also have found the mechanical gearing style:





More tinkering later today.

[Kilrah]

Thanks again. I'm thinking just wiring it in between the pots and my donor TX board.

That wouldn't work. The module expects and outputs servo signal pulses, not an analog voltage like you're dealing with in the TX.

One of those modified with custom software for 3x gain instead of 2x (or even 6x, while we're at it, to get 180° servo movement) and put between the receiver and servo would indeed compensate for the loss of throw. However, resolution might be noticeably low.

[mrfliboy]

Well it was a thought anyway, Thanks Kilrah


I pretty much stripped the donor Tx board down already, meaning removed the excess stuff that did not affect the ch 5 and 6. Reverse engineering the existing ch 1 thru 4 will be tough. The gear setup looks feasible. Thanks again

[mrfliboy]

Mechanical gearing is doable. One side tested and all is well. Almost 90 deg throw and no stops needed. Gimbal assembly came from the donor 4 channel radio. Lower gear is from a 1/4 scale servo and I used the original pot shaft without the electronics. Upper gear is from a std servo and the pot is from the 6 channel radio. Tomorrow attempt the otherside and hopefully by the weekend at least have this part done. Thanks for the help.

With a Mechanical tracker is it better to have the gimbal return to center and install the springs again or leave it with a little friction and no centering? Thanks

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[Kilrah]

I don't think it matters much , the springs wouldn't be strong enough for you to feel them anyway. Maybe if you put them it would bring the camera to center instead of an uncomfortable position should the mechanical assembly disconnect in flight, but I see no other advantage...

[mrfliboy]

Thanks for the info Kilrah. The centering springs will take alittle extra work to reinstall. I'll give it a shot. I've heard a few stories of cameras getting jammed in unfortunate spots.

[mrfliboy]

Iwas asked to post some pics of the PCB and also I've finished the gearing of the gimbals

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