Snarls Micro Brushed Quad - Build Log

[Snarls]

Alright it's time for another build! This time we're going even smaller; to the micro scale. Winter is approaching and that means short days, cold temperatures, and snow. To keep myself occupied I've decided to finally get something I can fly indoors. The Tiny Whoop and Nano QX are popular options, but I am a guy who likes to build and tune, so I am going to build something myself. Ever since getting a 3D printer last year I have this design from Thingiverse in mind. This should be a quick build, but I have not seen any brushed quad build logs on here so I thought I should document it.

The parts list is pretty much the same as what is listed on Thingiverse:

FC: SP3Racing EVO Brush
Motors: Chaoli 820 8.5x20mm
Props: Walkera QR Ladybird Props
FPV Cam: 600TVL 1/4 1.8mm CMOS
VTX: FX758-2 5.8G 200mW 32Ch
RX: LemonRX DSM2 Satellite
Voltage Regulator: 3V to 5V USB step up
Frame: 3D Printed from Thingiverse

I will be running Betaflight and using an OrangeRX module in my Taranis. Let me know what you guys think or share your own micro builds.

 

[PsyBorg]

Just had a peek at the video for that frame. That thing scoots around pretty good. Pretty agile as well. Hopefully your build does as well or better for you.

How soon before you start the build?

 

[LitterBug]

Interesting build. Gives me ideas of what to do with my Hubsan X4 107D. Flew it once and it's sitting in the corner because I hated just about everything about it. The way it flew, poor range, and crappy FOV on the FPV. I'm going to have to look at these brushed boards. Would be nice to have a slightly bigger FPV brushed quad than my Inductrix and BeeBrain Whoop for dome and gymnasium flying. Going to look for a brushed board capable of 3D.

Cheers!
LitterBug

 

[LitterBug]

Really like the description of the board:
2. The flight control support 1S (4.2V) and 2S (8.4V) power supply, 2S power can bring flying experience more violence.

We need more Flying Violence! ROFLOL!

Interesting that they call the controller an F3 EVO. It has none of the stuff of the "real" EVO other than the CPU. Different Gyro/Accel, No Magnetometer, no 280 Baro, no SD card. LOL Evo has the 9250 which is a 6500 with a magnetometer.

Still looks like a bunch of fun!

Cheers!
LitterBug

 

[Snarls]

How soon before you start the build?

Already started! It is pretty simple since the ESCs are built in to the board, but I am taking my time to get the wiring all nice and neat. I'm pretty busy early this week so I probably won't get it maidened until mid week. Unfortunately not DVR on my Quanum box googles so I'm not sure what I'll do to film it.

Really like the description of the board:
2. The flight control support 1S (4.2V) and 2S (8.4V) power supply, 2S power can bring flying experience more violence.

We need more Flying Violence! ROFLOL!

Interesting that they call the controller an F3 EVO. It has none of the stuff of the "real" EVO other than the CPU.

I'm sticking to 1s for now, but if I feel like getting violent I'll know what to do.

They recommend flashing the board using the SP3 EVO target in CF/BF, if that has anything to do with it. Maybe they just named it after whatever was trending that week.

 

[Snarls]

All the parts for this build. So little that they all fit on the scale.

 

[Snarls]

Battery lead soldered on.


LemonRX satellite RX cable soldered on.


Motor leads cut to length and tinned. Only two wires to deal with.


Motors soldered to the board. So simple with the lack of external ESCs.


Overview of the motors soldered on.


Everything mounted on the frame. Plug in the RX and a battery and you could fly this thing already.


Now time to add the FPV gear.

 

[Snarls]

I removed the original wires from the camera because they pointed off the side and would not be protected by the frame. The new wires are smaller and point towards the center of the camera.


Camera signal soldered to the vTX. VTX also soldered with power and ground. Camera will be powered off the battery and the vTX will be powered off the 5V from the UART. I'm hoping to avoid using the 3V to 5V step up because it will be hard to fit on the frame.


Spektrum satellite removed from case and mounted on top of the FC. Antennas stick out a bit so I bent them in slightly.

 

[Snarls]

This build is using a custom built antenna. I made one using some coax from a broken coax extension cable. The exposed part is approximately 12.8-13mm. I don't have calipers so I really can't get too accurate.


Next I soldered the antenna on to the vTX.


I soldered the power and ground wires and mounted the camera and vTX to the frame.


I put the top on the frame and its done! It is a pretty tight fit inside. Unfortunately I will have to remove the top part to access the USB port. The top is held on by this clip system, so it should not be too tedious to remove now and then.




Now I have to bind the receiver to my Taranis and get things setup in Betaflight. Then it is time to maiden!

 

[PsyBorg]

Wow That's a sweet little build mate. I have been mulling over a small indoor quad for winter around my apartment. I just wish Walkera used a more friendly protocol. Although they do use the same chip as the DSMxxxx receivers so it may bind right up. Was gonna grab the new FPV inductrix because it has the same chip but don't want to throw away 100 dollars on a test case just yet.

Can't wait til you maiden this beastie.

 

[Snarls]

Just realized I had this build log. And I never said anything about the maiden! Well let me tell you, the maiden was ... well I can't remember it was so long ago.

I flew this build only a handful of times until I broke a motor and had to go back to school before I could fly it again. It flew quite loose and I had to fly in level mode to get it under control. I also broke multiple frames from simple crashes. All in all it was fun but a little too fragile so I left it on the bench for awhile.

Then about a month ago I brought it back out. I flashed it with the latest betaflight and decided to spend some batteries tuning gains. That improved things tenfold. The flying is now much more stable and predictable. Still not miniquad stable, but good for a micro quad I think.

I also improved the frame design from punkkills design and made it much more robust. Additionally I've added some hot glue under each motor and a supporting spacer under each prop. Knock on wood but I have only broken props since.

I'm flying two capacities of 1s batteries; 300 mAh and 750 mAh. With the 300 mAh I get 2.5 mins of flight time with 'performance' acro. With the 750 mAh I get 7 mins of flight time with flips and rolls still possible, but with a 'heavier' feel. All up weight is only 40 grams without battery.

With the snow on the ground I think I'm going to be flying this a lot more this winter. Oh yea and now since I have some fatsharks with a DVR, you may see some raw footage of this guy flying around!

 

[LitterBug]

I have a few brushed things in the works. Indoor fly tomorrow night, so should have something posted up soon....

Cheers!
LB

 

[PsyBorg]

At first I thought that last picture showed it being like a drop forged aluminum frame with the texturing it seems to have in the pic. Is the camera angle locked with what seems to be a thru frame mounting?

 

[Snarls]

Ha drop forged aluminum would be sweet, but overkill. The camera is just hot glued in place to the piece extending off the top plate. The designer set the angle at 13 degrees which I find appropriate. Any more and I pick up too much speed for an indoor pace.

 

[Snarls]

Here is a quick edit of some of the DVR footage from today's club meetup. The gym was in use so we had to head to the lecture hall to take a new course in micro 101.

 

[Snarls]

For anyone who wants to build a micro with this modified frame here is a link to it on thingiverse: https://www.thingiverse.com/thing:2765197

I have crashed it pretty hard dozens of times now and I have yet to need to print another frame.

Additionally here is a tip that I included on the thingiverse page:
Add a spacer between the prop and the motor housing. This prevents the shaft from being rammed into the bottom of the motor casing in a crash, which could result in breaking the bottom piece. Also add a good dab of hot glue under the motor where the motor sits in the frame. This will strengthen the bottom of the motor, hold the motor on the frame, and reduce strain on the motor leads .

 

[PsyBorg]

COOL! Glad you are back and flying mate. That looked like a fun time ripping around the lecture hall. Shame you cant do that during class when the boring parts come.

Honestly professor. I was only using the camera to get closer to better see the blackboard!! These fluorescent lights kill my eyes and the FPV system filters all that so I can better learn what you are teaching!

 

[TEAJR66]

Here is a brushed micro frame designed around those electronics. The benefit to this frame is the bar at the bottom of the motor mounts that prevent the bottom of the motors from popping off.

https://www.thingiverse.com/thing:2765847

 

[Snarls]

Interesting frame TEAJR66. I will try it out if I ever move on from the current frame.

One thing I really like about the brushed micros is how innocent they seem. We encountered a few (albeit technically inclined) students while flying and they did not seem to even take interest in our micros. To outsiders the micros probably look like just a toy (which is not wrong). With miniquads and especially the larger gimbal totting quads like my Disco, people tend to take more interest. I was watching a video by KababFPV and he talks about this phenomenon. I'm not saying to purposefully fly close to people, but if you had to this is the size to do it with.

 

[TEAJR66]

They are fairly innocent in appearance. I can get away with flying them in places where people would freak out over larger quads. The form factor also lends to portability which keeps me much more mobile.

When you are ready for something that will give any larger quad a run for its money (or at least make people do a double take), make the jump to 2S. I put a set of 2S motors on one of my XF 95 frames, and it was insane. Minimum throttle was climb. I'm glad gravity was in full effect that day or it would have never come down. I had to pitch full forward to bleed off altitude and stay moving forward to keep from shooting up. There is no hover. Without wheels it was a tumble, rather than rolling, landing.