Just a while ago I wrote a brief build log for the FPV250 mini quad. I recently received the new Diatone Frames (FPV250LH – Low Hung or FPV250 V3) from Hobbyking, with some improvements I have in mind from the previous version, I decided to sell my old one, and rebuild the mini quadcopter with all brand new parts.

In this build, I will try to keep it minimal, no gold connectors, shortest wire possible and so on. I have requests for more step by step pictures of my build log last time, and that’s what I am going to do as well.

Check out the complete part list for 250 size mini quad for more options on motor, frame, ESCs, FC, and all other components.

Update: I have started a new build with a different frame.

A quick video.

As to the components and parts, it would be similar to my previous build. But if you have any question do check it out before asking.

Diatone FPV250LH V3 Frame

Cobra 2204 1960KV Brushless Motors

12A Blue Series ESCs with SimonK Firmware

Gemfan 5030 Propellers

Naze32 with Multiwii

Frsky DJT Transmitter and Frsky D4R-II Receiver

Turnigy 9X with er9X Firmware

SONY SUPER HAD 600TVL CCD Camera – PZ0420 with 2.8mm Lense

Mobius / GoPro

Super Simple OSD

ImmersionRC 5.8Ghz VTX

Turnigy Nano Tech 4S Battery 1300mAh/1800mAh

Weight ~ 630g

Flight time ~ 9 minutes with 1300mah, 12 mins with 1800mah.

FPV250 V3 Frame

Diatone released their FPV250LH V3 (clean and dirty) frame not long ago, which separates the cage from the main frame by some vibration-dampening rubber balls. This is not much different from the last version apart from this, all measurements, size of screws etc remain the same.

The only problem is when the cage is hung below the main frame, it’s awkward to mount the recording camera. So I was getting creative and rearranged the positions. I didn’t like the idea of “low hung” anyway, I think it causes the “pendulum” effect when the quad is making rolls, making movement more slowly.

It’s now effectively the previous FP250 version, but with a anti-vibration top plate for the Mobius / GoPro camera.

One of the downsides of this frame is weight.

Quadcopter Assembling

Right, let’s get to business.

Motors

Same as the last build, I will continue to use the Cobra 2204 motors. They are great for mini quadcopter, medium price but excellent quality. The 1960KV version is great for 4S battery setup, and the 2300KV version is perfect for 3S Lipo setup.

Remember to use washers at the bottom of the mount, otherwise the the screw might be pull through the holes, and the motor might come loose.

Now installing the prop adapters, I use some loctile glue to make sure the screws doesn’t fall out due to vibrations.

ESCs

I am using Hobbyking Blue Series 12A ESCs, all N-FET, cheap and programmable.

First of all, flash all 12A ESCs with SimonK Firmware. It’s very easy to do with these ESCs, I described how to flash these 12A ESC using Arduino in detail.

I also like to strip the 5V and GND cables for three of four ESCs, so the flight controller and radio receiver is only powered by 1 ESC. The reason I do this is because in Naze32, all BEC’s are connected together, and current is drawn when there is a voltage different (even very little). I found the ESC’s run cooler when the 5Vs are not connected together. Also, it’s a few grams lighter too! Every gram you save, is a few more seconds in the air.

But of course, this is unnecessary.

Now put everything on the frame, and measure the length of the wires, make sure they are long enough.

Power Distribution (PDB)

I am using 14 AWG wire to distributes power directly to the ESCs from the battery. I am not using PDB because I don’t like having the conductive surface exposed, any wet leaves get in there could potentially short your system. I also added a branch for voltage OSD, and another branch for the video transmitter / Camera.

To find out what wire you should be using, given the max current you might run in your system, check out this post.

Cutting the wires of the motors and ESCs to a reasonable length, and solder them together, finished with head-shrink tubes.

Electronics – Naze32, Radio Receiver, Video Transmitter and OSD, Power filter

The FPV250 Frame isn’t really designed for small flight controller like the Naze32, so you need to make your own FC adapter to mount it. Some people prefer to drill holes at the bottom, or simply use double sided foam, it’s all up to you. Here I made an adapter for this frame.

I am fitting the ImmersionRC 600mW video transmitter below the Naze32 to save some precious space. Voltage regulator and power filter sit at the back.

Although the ImmersionRC 600mW vTX accepts 4S Lipo voltage, the CCD camera only works on 12V, so I will be using the voltage regulator for both of them. To avoid any noise from the motors/ESC’s, I built a power filter for it.

And the radio receiver goes to the front. I am using CPPM, so there is only one cable connect for 8 channels.

And the OSD for Lipo voltage and timer is cable tied to the two spacers.

And finally mounting the Naze32, and connecting the ESCs. The white cable is for the bluetooth module, which allows me to do PID tuning on the field using my smart phone, without the need of a computer.

CCD Camera

You might ask why CCD Camera? Here is a guide explaining what makes a good FPV camera, and what CCD means.

To use the Sony HAD 600tvl CCD Camera on this frame, you will need to remove the edges of the board first.

To fix the camera on the camera mount plate, you will need some long M2 screws, nuts and spacers (or rubber balls).

This is recycled from my last build, look how dirty it is! :)

I put more washers on the top screws, so the camera is tilted upward, which allows me to see more when the quadcopter is flying forward. This is especially useful if you are a quad racer who loves speed.

And this is what I am getting.

Dirty and Clean Plate

Don’t mount the antenna on the video transmitter directly, it could easily rip the antenna mount off the PCB of the vTX. I learned the lesson a while back, although I managed to fix it by soldering it back, but the range decreased a lot.

I prefer to use a coaxial extension cable, have the antenna mount end fixed on a piece of plastic sheet (or just use one of the rubber ball holes on the frame).

The camera mount is made from these anit-vibration stickers.

And I also run zip ties through the rubber balls.

Final Touch

Flight Controller Settings

Naze32 settings on this mini quad is discussed on this post. Here is the first flight:

Rolls of Death!

Not sure what caused this, I still need to bench test it a bit more. Here is some background of the crash.

It rained earlier, the grass is a bit wet, I flew happily for 20 mins, and had a few minor crashes, so some components might have got wet grass on/in them.

After another take off, all of a sudden, it just started to spin like crazy, and eventually crashed into the ground. I rushed to the crash site. I lost radio control, because of the radio receiver antenna came loose. But the motors are still spinning.

I took it home, plugged everything back together, and it seems working fine. But I noticed the bottom right ESC heatsink went missing, and there are grass stuck in between the FET chips.

Was it the ESC/motor? Was it the flight controller? Or was it the radio receiver?

After consulted with my friends, we all think it was water that got into the flight controller, and caused it to malfunction. Lesson learned! Never flight during rain, or right after rain!

In today’s flights, I managed to break the frame in a few places, all at where the holes are (where the rubber balls sits). It reveals the weak points in this new frame. These holes are cut so big, it does not leave much glass fibre to hold it together.

Damage Report

The last crash in this video broke the arm of the frame.

Another Damage Report

I am not sure if it’s me flying more and more aggressively, or the FPV250 frames are getting crappier, or just simply pure bad luck, this new frame only lasted one week. It snapped almost on the same spot as the last one.

The crash at the end of this video did it. I was so frustrated, as I just arrived the park, and it was my first lipo pack!

I just placed an order for a blackout 250 chinese clone frame. They are about 1/5 of the price of the blackout mini quad, and the spec looks very much the same. I have heard good feedback from others, apart from the carbon fibre cuttings, and hole drilling look bad.

I now have only one FPV250 frame left. If that breaks as well, I will be trying the new QAV250 (C250) Frame, .watch out guys for my review on that. It’s really time consuming to assemble a quad.

Customized DIY Camera Mount (update 23/08/2014)

So one day after many crashes, I came home with two broken top plates. What am I going to do with them, I wondered. I know! I am going to turn them into a small camera mount. Since I have good luck with the V2 frame, I can combine them to create a “Semi V3” frame, and have the best of both worlds.

Use all six holes to get the best dampening effect.

Do not put screws on the top plate yet.

Motor mount Arm snapped again in Crash! (Update: 09 Sep 2014)

My last FPV250 frame finally died after many days of service. I don’t think it can take any more of my abuse, and finally given up! LOL

But no need to shed tear, I will be building another one with the Carbon Fibre 250 Mini Quad frame which I reviewed a few weeks ago. It’s really not a safe spot to break on the arm, where the motor mount is. The motor wires was tore and a little bit of copper wire is now exposed.

This is the last minute video of this frame… RIP