First FPV drone, first build, first attempt at soldering - Martian III


#21

Haha yeah, blink and there is something new! But I suppose that is what makes it quite enjoyable if you always want to learn stuff :slight_smile:


#22

Awesome, that was actually pretty easy using the Chrome app. I reversed 2 & 3, so they now spin correctly.

To stop motor two twitching @ 1137, I went back into the ESC config and tweaked the ‘PPM Min Throttle’ on ESC 2 from 1148 microsecs to 1152. That particular spasm has gone away, and they all start spinning at 1153 in the Betaflight software.

I reckon I’m good to go! Thanks for the pointers (again!). Will try and get out with it this weekend. Will prolly order some more props on monday lol.


#23

It hovers indoors! Blimmin loud though. More of an outside toy :smile:

Not all the rotors spin up at once as the power is slowly increased from 0, does this cease to be an issue once airborne and all spinning or is it something that will lead to instability? Is it a tweak of the ESC or the FC?


#24

Well… it’s pretty solid. Survived being sprinted into the ground upside down at high speed. :laughing:

Rotors didn’t though! Very sensitive controls. :+1:


#25

Haha… how most first flights end up… usually a good idea to practice is horizon mode to start off in :slight_smile:

As for.all.the motors not starting at exact time, as long as they all startup in betaflight motor test at the same time then this is normal. As sometimes you might not be taking off from an exactly level surface.


#26

Ok, Aux switches activated, Angle, Horizon and Air mode all bound. Hopefully will have more chance!


#27

Have had it flying, and kept it in the air for 5 minutes or so, and only crashed it lightly at the end 'cos the sun was in my eyes. Lost a single prop, so that’s progress, I guess!

Would the drone be able to take tri-blade props? It has 2 atm, what difference do they make - do you get more lift for the same throttle (imagine there may be more strain on the motors?) or isn’t not quit as simple as that?


#28

As a rough guide, 3 blade props will gibe you more thrust, but as you said they will also put more strain on your motors and tri blades are also usually less efficient.

Some pilots also prefer 3 blade props as they also feel more stable.

The motors and ESC you get with the Martian kit can take 3 blade 5inch props no problem as you get a set of 5045 Tri blades with the kit


#29

Well… finally got the last bit sorted! Am looking forward to giving it a go.

Thanks for all your help everyone!

Another prop question - can’t find 5030s anywhere - presume 5040/5045 will be ok? Read some stuff that seem to think the 5045s are more stable? Presume will use battery faster though.

Also, how would you go about recording the video?


#30

Yeah you can use 5040, or 5045 props with those motors, and yeah they will be abit faster.

To record the video you need to use a DVR… but I dont think your monitor has one built in, so the options are:

  1. get a separate DVR and hook it up to the vidoe out of your monitor (or open up the monitor and integrate it (not reccomneded unless you know what you are doing))
  2. Get something like this HD FPV camera+DVR. This is technically better as it records in HD onto the SD card, but can still be used as a regular FPV camra.
  3. Get a gopro sesson (or similar) and mount it to the top of your drone:

or as a cheaper alternative


#31

Thanks again!

Have just bought some disc LEDs to sit under the motors (only to make it easier to see orientation), 5v, do I attach them to the input pins on the FC, post BEC? It won’t cause potential to drop too much will it?


#32

Hard to say for sure as not sure what power your LED’s require. Can you send a product link so I can offer better advice.

But most led should not draw too much current so will probably be fine to connect to a bec assuming it can handle at least 2A.


#33

Hey Alex, thanks for replying.

Sure thing, they are 5v lights:

From your answer, as long as it’s from the output of the bec it will be fine. The inputs to the FC are easier to get at. Will that affect the FC at all?

Cheers!


#34

Becareful when adding things like LEDs to the FC or a BEC.
The FC onboard 5v BEC or external BEC will have a output rating in Volts and Amps.
If you pull more Amps than what its rated you could pop the BEC or cause a brown out.

For example an FC has a 5vdc bec rated at 1amp

You attach a VTX that pulls 0.6 amps
you attach LEDS a 0.12amps x 4 LEDS = 0.48amps
Thats over 1amp and nots including a Rx.


#35

Spot on, exactly the kind of thing I was looking for. I wondered if it would be as simple as ‘solder this here’.

So, if, say, the BEC isn’t up to the job, what then? Upgrade the BEC? Maybe put a second on dedicated to the LEDs?

Specs: This is the BEC (5v one): https://www.unmannedtechshop.co.uk/mini-bec-v2-voltage-regulator-3-3v-5v-12v/

…and these are the requirements of the LEDs:

Input: 4-6V DC
Power: 0.6W @ 5V *0.12A

The FC doesn’t seem to have current draw specs.


#36

The BEC you have is rated for 2A
looking at your build.

FC draw is low
HS1177 0.7A
FPV Tx 0.3A
Rx Low
LEDS 0.12A x 4 = 0.48A

Total = 1.48Amps

Thats assuming your running everything off the same 5V Bec.

If you can list your parts and what they are connected to. I can take a better look for you.
I think your problemly be fine.


#37

So this is pretty much the connection diagram:

with the addition of the FPV, but that takes it’s power directly from the battery connector on the PDB.

This is the (relevant) kitlist:

4 x ChaosFPV CF225 2300Kv Motor (2 x CW, 2 x CCW)
4 x Chaos BLHeli_S 25A ESC
1 x SP F3 Flight Controller (Acro)
1 x Mini 5V BEC

However, most of that is connected to the PDB.


#38

You should be fine then.
I think


#39

I think

:rofl:

More seriously, I think so too. I will have a go! Many thanks!


#40

Enjoy and double check everything with a volt meter and continuity checks before pluging for the first time

Please make sure your props are off too :slight_smile: