Micro-Tri Build Log


Senior Member
This build will be one for the long haul as I'm still figuring things out as they go. After I made my micro quad I really wanted to build a micro tricopter but was stuck due to servos being too large to build a micro. Well one day I stumbled across this servo https://www.servocity.com/html/hs-5035hd_servo.html#.Vxwhs_krL1s and it gave me hope a micro tricopter was possible. There is a cheaper non-metal gear servo HS-40 which is roughly the same size but 1/3 of the price. I'll be going with the HS-40 if this servo doesn't hold up.

Anyways, once I found this servo I started brainstorming ideas for the frame. I got a little too ambitious and started cutting and printing parts for the frame. I had plans of mounting the FC under the main frame and then the FPV gear would go in the top portion. I had planned on using a CC3D Atom, then an EMAX Skyline32 Mini. I bought an Atom but ended up bricking it trying to flash Cleanflight. I didn't watch the tutorial all the way through where you had to apply 5v to some pads so the computer kept disconnecting the board when I would try to change settings. This issue coupled with the fact there wasn't a good way to mount it made me look for other options.

This is where the EMAX Skyline32 Mini came into play. It's supposed to be a Afro Mini clone that has the USB connector on the board. All of this sounded great so I ordered one from an Ebay seller. A few weeks go by and my package hasn't arrived although I received shipping confirmation. I contacted the seller and got a refund so now I'm on option three. This time I'm going with the Afro Mini from MRSS and it should be here Monday.

I ultimately decided on this board as I have plans to make a PDB and have it slot into place. This will solve the issue of mounting the FC to the frame, and will make all of the wiring really easy. Jason mentioned to me OSH Park does 4 layer boards, and they have an option for 2oz copper, so I'll be sending this board off to them once I get the design finalized. The Afro Mini will be held in place in the front by the servo pins, and a few in the back for support. The ones in the rear won't be attached to any of the planes in the PDB; they are just there for mounting purposes. The Pololu2107 regulator may be replaced with this one from MRSS (on order too) as it has a higher amperage output than the Pololu https://www.multirotorsuperstore.com/accessories/power-accessories/regulators/adjustable-dc-to-dc-mini-step-down.html.

Top layer is pads and signal traces, second layer is ground traces, third layer is the positive plane, last layer is the ground plane.

Do to the size of this build I had to mount the ESCs as close to the motors as possible. To do this I looped the motor wires under the ESC and ran them across the top and soldered them to the pads. I threw on some power wires and ESC signal/ground wires while I was at it before covering them with heatshrink. The PDB will sit on top of the printed part as well so the solder connections won't contact the frame underneath. This will also let me pass a battery strap under the PDB so it doesn't have to go across the voltage regulator.


And one last one for size comparison. This is the tri next to a Nanotech 1300mah.

Hopefully more will come sooner rather than later. For now I need to continue working on the next 3D printed part and how I want to mount the FPV gear. I'm going to need an extremely small camera for this build if I want to keep it all hidden. I plan to model an enclosure for the VTX and mount it to the top of the tri, but I would like to keep the camera inside and hidden if possible.


Faster than a speeding face plant!
Interesting solution on the motor leads, Twitchity. Very innovative I think. ;)

What motors/ESCs are those?


Senior Member
Interesting solution on the motor leads, Twitchity. Very innovative I think. ;)

What motors/ESCs are those?

Not really, I saw someone do this on an Atom or another sub 130mm quad. I just stole their idea and used it on my build. :)

The motors are DYS 1306 4000kv, and the ESCs are DYS XM20A. Ordered a cheap micro FPV camera last night from Banggood as I'm not sure if it's going to fit, but for $10 it was worth the risk. Plan is to make this run on 4S.


Ordered a cheap micro FPV camera last night from Banggood as I'm not sure if it's going to fit, but for $10 it was worth the risk. Plan is to make this run on 4S.

I love my $10 CMOS from Banggood, its quality is close to even the best CCDs.


Senior Member
this is gonna be cute.. i think the nano qx needs a tri sister.. so good luck.. this is the cc3d mini i purchase for my 130mm insect build
its small as heck.

about the size of a.25
cc3d mini small.png

as you can see the mini is in the middle with a regular cc3d 32x32 or whatever the standard is, and the a atom on the left.

no shortage of FC on my desk. laughs. now a PDB and 5v bec yeah i need to stock up i guess. :D i do have one polou 5v i plan on using with the 230mm martian.

but, yeah damn little parts add up. wish i just had a shelf full of parts that would keep them self's stocked :D