Using +V out 3.3v pin

Info and discussion about the autonomous Micro FC, suitable for nanos, micros and mini multirotors

Using +V out 3.3v pin

Postby Flyer324 » Thu Mar 05, 2015 8:59 pm

Can I use the +v Out 3.3v pin on the J2 header to power a video TX and camera using about 350mA current? would I just connect the ground to power ground or to the DGND pin?
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Re: Using +V out 3.3v pin

Postby kinderkram » Thu Mar 05, 2015 10:08 pm

I´d rather take an ext. voltage regulator for video tx and power it from the lipo directly.
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Re: Using +V out 3.3v pin

Postby Flyer324 » Thu Mar 05, 2015 10:20 pm

I agree... I'm using this TX. http://www.foxtechfpv.com/product/5.8G%20modules/tx5823/TX5823-Spec-V1.pdf

and a 3.3v pololu stepdown regulator... https://www.pololu.com/product/2106

but when i ordered the pololu board i didn't realize it needed a voltage of atleast about 4.3v to operate. So now i have no way left to power my TX... probably should have went with a 5v tx and a step up regulator.

Guess I could order a 3.3v stepup/stepdown from pololu like this https://www.pololu.com/product/2122

but it sure would be nice to just use the M4's 3.3v Is it to much current for it?
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Re: Using +V out 3.3v pin

Postby Flyer324 » Thu Mar 05, 2015 10:37 pm

This is the baby I'm working on :)
Attachments
IMG_20150305_115609183_HDR.jpg
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Re: Using +V out 3.3v pin

Postby kinderkram » Thu Mar 05, 2015 11:15 pm

Nice baby.

But it´s not only about the current but the voltage.
A 5V stepup would be the way to go. I dunno why you bought a stepdown in the first place?
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Re: Using +V out 3.3v pin

Postby Flyer324 » Thu Mar 05, 2015 11:20 pm

because of the video TX needs 3.3v according to the PDF but lipo voltage gets to 4.2 fully charged. thought what was too high and the 3.3v stepdown would keep it at a nice 3.3v for the TX........
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Re: Using +V out 3.3v pin

Postby aBUGSworstnightmare » Fri Mar 06, 2015 6:19 am

The S7V8F3 is the better choice. Please notice that this type of equipment can get quite hot during operation.

I wouldn't recommend to power such type of equipment from the M4.
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Re: Using +V out 3.3v pin

Postby Flyer324 » Tue Mar 10, 2015 10:51 pm

Thanks i used that module and it works perfectly now.
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Re: Using +V out 3.3v pin

Postby Max » Wed Mar 11, 2015 12:26 am

Are you getting any interference (horizontal lines) on video when the motors are running?

I have a similar setup (sort-of) with a Polulu step up/down from the 1s flight battery. Crystal clear video until the motors spool up. I was hoping the v-reg would provide enough filtering, but maybe not (or I have some other issue).

Nice looking bird BTW. I like the C-clips for the motors too, good idea. What's the AUW? I saw on RCG that you're thinking of selling 'em?

Cheers,
-Max
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Re: Using +V out 3.3v pin

Postby Flyer324 » Wed Mar 11, 2015 1:11 am

Thanks!
I do like the c-clips because it lets you change out the upper plate for a blank one to just fly around without video gear easy

Yes selling them was just a thought to compensate for how expensive this hobby has become for me :) and i don't mind building them.

I do get some slight interference in video when motors are powered but it's not to noticeable. I think a small say 300-400 uf capacitor will help smooth the power and fix that. it would be nice to find a TX module that does not need voltage regulating board.

Do not know the AUW but a scale is on the way. Something I've needed for a long time. I'll have to get a hover flight time for it.
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