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Old Jul 08, 2013, 01:41 PM
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Ok, so I fear we are at a cross road.... And I wanted to get everyone's comments.

Evvaldis, I really hope you'll contribute as I hope you are back from holiday...

There seems to be enough interest to spin a design with drivers and N-FET's. This design appears to be *more robust* both current and voltage wise over the original design and would seem to provide support for larger motors which I know some of you want.

It's very much in the study phase, with some proposals around components. So far (and remember all this is on paper at the moment, nothing proved in hardware), it would also appear to be software compatible. - Course I'm not even sure that matters because software is very much behind the hardware at the moment anyway. But it may allow one code base to support both designs.

For the sake of discussion, let's call the 2 designs. pre1.3ce2 (which I'll most likely release based upon this discussion) and what I'll call pre2.0.

pre1.3ce2 will be the current design with a few incremental changes from the ce1 release that I provided.

pre2.0 will be a design incorporating the new driver/N-FET design

So.... what to do...

Do we ???

a) release a pre1.3ce2 (schematic and gerbers) and let those that want - play around with that design. In parallel continue a pre2.0 design

OR

b) Stop any release of pre1.3ceX and just focus on a pre2.0

I will tell you there are enough unknowns with pre2.0 that the way I'd *strongly suggest* it be released is as follows.
- once the design and layout is formalized, order a *few* boards and a *few* people assemble and test those boards. (at this point, only release the schematic - not the gerbers)...
- once the design is proved out, then release the gerbers and ya all have a party...

Comments?
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Old Jul 08, 2013, 02:10 PM
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I personally really want to be moving large cameras with this board, so pre2.0 is more exciting to me- but I'm also antsy to get my hands dirty and start contributing more than the random idea tossing that I've done so far. I also predict that we will run into problems sourcing large enough motors for larger cameras, but that's a whole other can of worms.

If the software is compatible (or close enough) with both boards, much progress can be on software side using pre1.3ceX and then later applied to pre2.0 when it is further along in development. So it wouldn't be wasted effort to release 1.3ceX now and let people play with that, continue to develop the software, and push things forward while the next gen hardware is coming out.

My only reservation to that plan is that it could slow progress on pre2.0, which I'd like to keep pushing. Seems like Alan, Rull, Pilt and Bektorkhan are the brains on pre2.0 development, so I'd defer to them on how they want to spend their time.

As I've said several times, thank you guys so much for your efforts and interest in this. Very exciting to see it move forward so quickly.
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Old Jul 08, 2013, 02:20 PM
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Quote:
Originally Posted by aadamson View Post
Ok, so I fear we are at a cross road.... And I wanted to get everyone's comments.

Evvaldis, I really hope you'll contribute as I hope you are back from holiday...

There seems to be enough interest to spin a design with drivers and N-FET's. This design appears to be *more robust* both current and voltage wise over the original design and would seem to provide support for larger motors which I know some of you want.

It's very much in the study phase, with some proposals around components. So far (and remember all this is on paper at the moment, nothing proved in hardware), it would also appear to be software compatible. - Course I'm not even sure that matters because software is very much behind the hardware at the moment anyway. But it may allow one code base to support both designs.

For the sake of discussion, let's call the 2 designs. pre1.3ce2 (which I'll most likely release based upon this discussion) and what I'll call pre2.0.

pre1.3ce2 will be the current design with a few incremental changes from the ce1 release that I provided.

pre2.0 will be a design incorporating the new driver/N-FET design

So.... what to do...

Do we ???

a) release a pre1.3ce2 (schematic and gerbers) and let those that want - play around with that design. In parallel continue a pre2.0 design

OR

b) Stop any release of pre1.3ceX and just focus on a pre2.0

I will tell you there are enough unknowns with pre2.0 that the way I'd *strongly suggest* it be released is as follows.
- once the design and layout is formalized, order a *few* boards and a *few* people assemble and test those boards. (at this point, only release the schematic - not the gerbers)...
- once the design is proved out, then release the gerbers and ya all have a party...

Comments?
Hi, I am back.

Since it is almost impossible to make cheap, small, high voltage and current controller, I think that it is good idea to make 2 separate hardware versions based on the same software.
1. cheaper for gopro/nex/smallDSLR with current N+P mosfet configuration (maybe it is good idea to put PTC fuse if there is none already, and to make small bullet proof version)
2. more expensive and complex for dslr+.. In this version price and size is not the most critical factor, therefore we could use more expensive parts if it gives advantage.

P.S. I am happy that there is so much interests in this project!! And since I am back, will continue to work on this project.
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Last edited by evvaldis; Jul 08, 2013 at 02:32 PM.
Old Jul 08, 2013, 02:26 PM
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Quote:
Originally Posted by evvaldis View Post
Hi, I am back.

Since it is almost impossible to make cheap, small, high voltage and current controller, I think that it is good idea to make 2 separate hardware versions based on the same software.
1. cheaper for gopro/nex/smallDSLR with current mosfet configuration (maybe it is good idea to put PTC fuse if there is none already, and to make small bullet proof version)
2. more expensive and complex for dslr+.. In this version price and size is not the most critical factor, therefore we could use more expensive parts if it gives advantage.
I think I'm leaning to this direction as well.

One comment however, the driver/NFET design really isn't that much more expensive. I found both carried by digikey and the driver was like $1.50 us and the FET was less than a $1.00 if memory serves me right.

Granted, the final parts aren't picked yet... but yes it does probably mean we should release the pre1.3ce2 version so people can *play* ...

What I need on the polyfuse is what we think the max current draw is... For some reason on the alexmos version, they chose a 500ma hold, 1A trip polyfuse and that just seems too small... I'm assuming you'd want it on the lipo input. So someone tell me what you think the current draw is going to be and I'll see *how large* the polyfuse might be ...

Alan
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Old Jul 08, 2013, 02:27 PM
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I think evvaldis idea of two separate hardware designs would be good, a light version and a HD version, that runs the same software. This way we could get some boards built and get the software caught up while the new HD board is being designed.
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Old Jul 08, 2013, 02:57 PM
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Quote:
Originally Posted by aadamson View Post
I think I'm leaning to this direction as well.

One comment however, the driver/NFET design really isn't that much more expensive. I found both carried by digikey and the driver was like $1.50 us and the FET was less than a $1.00 if memory serves me right.

Granted, the final parts aren't picked yet... but yes it does probably mean we should release the pre1.3ce2 version so people can *play* ...

What I need on the polyfuse is what we think the max current draw is... For some reason on the alexmos version, they chose a 500ma hold, 1A trip polyfuse and that just seems too small... I'm assuming you'd want it on the lipo input. So someone tell me what you think the current draw is going to be and I'll see *how large* the polyfuse might be ...

Alan
If we are making "HD" (v2) version of EvvGC, would be nice to design it as robust as possible. Not just to add new mosfet drivers, but also to add over current(lets say with shunt resistor+comparator+hardware shutdown)protection, over voltage protection. Protections on GPIO(Resistor+TVS). And other things that will make this board heavy duty.
Those changes definitely will increase price of the board, and maybe even size.

If i remember correctly, my setup with 3x5010+DSLR eats up to 1.5A So I think ~1.5A holding current is enough for this version. Problem is that most of ~1A+SMD PTC is less than ~10V.. And radial PTC looks ugly...
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Old Jul 08, 2013, 03:13 PM
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Fully agree with you Evvaldis! The more robust the better for the HD version. I will gladly pay 2 or 3 times the amount for a board that can handle a red epic or equivalent! Still an unbelievable bargain compared to the 15K Movi from FreeFly!
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Old Jul 08, 2013, 05:41 PM
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Hi all,

Having been working on the v2.0 design, my thoughts are this.

Software should be compatible across both boards as much as possible (Flag in config to set board, only code changes to support fault monitoring)
Cost should be kept reasonable, target maximum twice as much
Board size the same (It makes it more fun trying to keep it the same size! )
For adding the majority of these protection features, we just need to switch from FAN7388 to FAN7389.

The extra expense can then be put on the mosfets, allowing us to chose lower RDS on Mosfets in better thermal packages

Tom, when you say larger cameras, what size do you have in mind?
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Old Jul 08, 2013, 06:03 PM
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Quote:
Originally Posted by Pilt View Post
Hi all,

Having been working on the v2.0 design, my thoughts are this.

Software should be compatible across both boards as much as possible (Flag in config to set board, only code changes to support fault monitoring)
Cost should be kept reasonable, target maximum twice as much
Board size the same (It makes it more fun trying to keep it the same size! )
For adding the majority of these protection features, we just need to switch from FAN7388 to FAN7389.

The extra expense can then be put on the mosfets, allowing us to chose lower RDS on Mosfets in better thermal packages

Tom, when you say larger cameras, what size do you have in mind?
A red with some glass can weigh in around 3-5kg.

My 5d3 with some primes is 2-3kg.

I don't think we would be looking at anything heavier as it would make an unusable rig.
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Old Jul 08, 2013, 06:05 PM
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@Pilt
10ish lbs would be a good place to start- that's 5lbs for a Red Epic, and 5lbs for lens and remote follow focus motor. Others may have more specific numbers as they may be running up to 3 motors for zoom/iris/focus, and might use heavier lenses.
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Old Jul 08, 2013, 06:28 PM
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Ok, here's what I think I'm hearing...

I'll go make the handful of changes to the pre1.3ce2 version and release it with schematics and gerbers. (will take me a couple of days as I've got a business meeting tomorrow that I"m getting ready for ... Semi retired only pays for some of the fun toys - gotta work to pay for the rest.).

Then we'll focus on pre2.0 with all the wild changes...

@Pilt... Sheesh 28 pin drivers and a 50x50mm board... oh the joy of it all ... Sure hope you can kill a few parts as is and still leave some room for a couple of other things that are needed ...

Alan
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Old Jul 08, 2013, 07:10 PM
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I think we need to make a fix for people with the 1.2/1.3 version.. !!

I suggest we skip the pull down resistor on the N-Fet gate, and add a pullup resistor to 12V of 3,3 kohm instead, to ensure that the low side is driven better.

Since there is a pull down on the BSS123 for the high side it should not cause any turn on problems.

I'm tired so verify my thoughts on this..! Good night..
/Mikael
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Old Jul 08, 2013, 07:17 PM
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Brushless Motor for Red Epic o more..!!

Hi Everyone,

As it is very difficult to get BRUSHLESS MOTOR for cold heavy, take the initiative to disarm the motor Maxon 90 mm ​​to rewind.



It's a big motor 90 mm ​​wide, is heavy and expensive. But as many here would like to find the solution for the cameras over 5 kilos, that's why I take it apart to see if it works and make it a gimbal motor.







Now that I have it disassembled, I hope you can help me:

a) which already use copper wire: 0.18mm
b) How many laps I have to give each segment?
c) and connect: Delta or star?
d) The drivers you mentioned, is in a position to move this motor?
e) the driver may move 3 motors the same?
d) have to change the driver?
f) we must modify the software?

Any comments or advice is very welcome you.

many Thanks
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Old Jul 08, 2013, 07:30 PM
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Quote:
Originally Posted by bektorkhan View Post
I think we need to make a fix for people with the 1.2/1.3 version.. !!

I suggest we skip the pull down resistor on the N-Fet gate, and add a pullup resistor to 12V of 3,3 kohm instead, to ensure that the low side is driven better.

Since there is a pull down on the BSS123 for the high side it should not cause any turn on problems.

I'm tired so verify my thoughts on this..! Good night..
/Mikael
Mikael,

No hurry, think it through tomorrow, etc and just post a note about what you think needs to be done and I can pull that into the pre1.3ce2 version.

Thanks for taking the time!
Alan
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Old Jul 08, 2013, 07:32 PM
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evvaldis,

Can we get an update on the software, and it's moving to Git, Eclipse, etc? Seems that's going to be the area of focus as soon as we get to this 1.3x version...

Thanks,
Alan
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