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Old Aug 24, 2011, 02:52 AM
That tree again!!!!
thanhTran's Avatar
Germantown, MD, US
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Originally Posted by ddchan View Post
thanks thanh, do you think using the 10amp plush escs with the 5g motors will be to heavy?
edit: just to be sure, but there is a i2c version of your code right? so I can use it with a clone motion plus (I accidentally destroyed at least one pad on all my murata gyros whilst desoldering *sob* )
I think the weight of the 10A Plush is fine. You can remove the big regulator (BEC) on 3 of the ESC's to make them lighter and smaller. Still working on your schematic.

-Thanh
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Old Aug 24, 2011, 02:52 AM
That tree again!!!!
thanhTran's Avatar
Germantown, MD, US
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Originally Posted by Woozer View Post
Hi All, this seems like a great project!

Just a quick question, are the ufo8 motors just driven by a FET and the controllers PWM output channels?
Yes!
-Thanh
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Old Aug 24, 2011, 03:46 AM
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Once again, thanks I shall order the 10A esc along with 5x3 propellors then.
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Old Aug 24, 2011, 04:43 AM
That tree again!!!!
thanhTran's Avatar
Germantown, MD, US
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Originally Posted by ddchan View Post
@thanh , once again thanks, ill upload the eagle file later. (please help me fix everything)
Hi ddchan

Here is the update cad file. I hope I don't have any mistake.
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Old Aug 24, 2011, 05:24 PM
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Originally Posted by thanhTran View Post
Yes!
-Thanh
Thanks for the info, won't you need a resistor to pull the gate down to turn the FET off when de proc is down? (no pwn signal)

and could you please tell me whee the 47uf cap on the powerline is for?

Thanks!
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Old Aug 24, 2011, 05:50 PM
That tree again!!!!
thanhTran's Avatar
Germantown, MD, US
Joined Sep 2004
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Originally Posted by Woozer View Post
Thanks for the info, won't you need a resistor to pull the gate down to turn the FET off when de proc is down? (no pwn signal)

and could you please tell me whee the 47uf cap on the powerline is for?

Thanks!
The PWM output of the MCU is still active even if the MCU is going to sleep. The pin is not floating or high impedance. I don't see the need for a pull down resistor.

The 47uF cap is to prevent fluctuating on the power line (filter). When the FET's open / close, the voltage on the power line will be spike up/down. The cap kills these.

-Thanh
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Old Aug 24, 2011, 06:26 PM
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Originally Posted by thanhTran View Post
The PWM output of the MCU is still active even if the MCU is going to sleep. The pin is not floating or high impedance. I don't see the need for a pull down resistor.

The 47uF cap is to prevent fluctuating on the power line (filter). When the FET's open / close, the voltage on the power line will be spike up/down. The cap kills these.

-Thanh
I learn more every day, The cap seems logic now.
So the motors power down when there is no power to the cpu (no sleep mode, just no power to cpu at all, so no pwm signal).
I thought a pull-down resistor is not normally necessary as the I/O pin pulls it high or low but what happens when the pin is floating as is the case during reset / power down or if it hasn't been programmed as an output? In this case won't any stray voltages tend to turn on the MOSFET?

well, I'm new to electronics so... never mind me
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Old Aug 25, 2011, 01:07 AM
That tree again!!!!
thanhTran's Avatar
Germantown, MD, US
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Originally Posted by Woozer View Post
...
So the motors power down when there is no power to the cpu (no sleep mode, just no power to cpu at all, so no pwm signal).
I thought a pull-down resistor is not normally necessary as the I/O pin pulls it high or low but what happens when the pin is floating as is the case during reset / power down or if it hasn't been programmed as an output? In this case won't any stray voltages tend to turn on the MOSFET?
...
Yes, in the case that the MCU pin is programmed as high impedance then the motor might run on its own. Or if you disconnect the FET gate from the MCU pin then the motor might start running. Any of these cases is not happening in my design as the FET will never be disconnected from the MCU, and right after reset, the pins are in a defined state. If you design an ESC to be unplugged and plugged, then yeah, go ahead adding the gate-ground resistor.
I'm not a hardware engineer so I could be wrong .
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Old Aug 25, 2011, 01:08 AM
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@thanh, thanks for the schematic, will make a layout now.

edit: does anyone know a good tutorial on how to use EAGLE's pcb board designer properly? Or can someone help me design a single sided board?
Thanks
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Old Aug 25, 2011, 10:23 AM
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Originally Posted by ddchan View Post
@thanh, thanks for the schematic, will make a layout now.

edit: does anyone know a good tutorial on how to use EAGLE's pcb board designer properly? Or can someone help me design a single sided board?
Thanks
Yes, here:

Cadsoft EagleCad Tutorial Lesson 1 (1 min 36 sec)

(12 eps of 5 min each or so)
W
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Old Aug 25, 2011, 08:48 PM
My RC builds in my profile.
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OK I managed to pick up one of the fabled Superdave42 frames.

I have 2 Snelflight saucers for parts as well as a Jumpjet en route. I imagine things have progressed since the frame was cut, and I can source a lot of the parts from hobbyking? I ordered a copter control in hopes I can use it for this small project, if not I'll work with a different frame.



Was browsing The Alien air thread and a lot of the information is outdated, links broken etc.

http://www.rcgroups.com/forums/showthread.php?t=813134

http://www.rcgroups.com/forums/showp...postcount=2240

I need some standoffs of some kind. I noticed some guys are using 040 carbon rod glued in place, but I'm not fond of that idea. Something replaceable would be better.
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Old Aug 25, 2011, 09:23 PM
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Originally Posted by ddchan View Post
@thanh, thanks for the schematic, will make a layout now.

edit: does anyone know a good tutorial on how to use EAGLE's pcb board designer properly? Or can someone help me design a single sided board?
Thanks
I would suggest exporting that schematic into DipTrace as soon as possible and then using the layout tools there. You can thank me later.
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Old Aug 26, 2011, 01:49 AM
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wow, thanks timecop, I like the auto placement function its really useful. Do you know how to get it to add holes to where jumpers should go if once it finishes autorouting?
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Old Aug 28, 2011, 11:02 AM
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hmm would 3x2 props be to big for a mini quad? (< 4'' ) (using ufo#8 motors)
they are easy to find than the silverlit props
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Old Aug 28, 2011, 06:49 PM
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wow, thanks timecop, I like the auto placement function its really useful. Do you know how to get it to add holes to where jumpers should go if once it finishes autorouting?
I've never auto-routed single-layer boards, but I do believe you can just choose 'single layer routing' and tell it to 'use jumpers' and it should be able to route that stuff up for you, automatically adding jumper wires. Might have to play with 'default via' style as it probably uses that for jumper wires as well. Tried the manual?
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