FPV Racer Quadcopter Build Log

Posted by on June 3, 2015 No comments

The summer is coming and it is time for FPV flying. It is just great feeling to fly around. In the past months I have used mostly my SG Acro quadcopter and that one is not suitable for FPV flying, even it is great fun making flips with it 🙂

I will be using my own SG Adventure Mini v4 frame. I spent many hours learning CAD from zero and trying to create an unique FPV frame, that is as good as possible. I just love this asymmetric carbon fiber frame 🙂

Let´s get started with the parts that I have used for that FPV Racer:

  • SG Adventure Mini v4 frame
  • T-Motor MN2206 2000kv
  • HK BlueSeries 12A ESC flashed with SimonK firmware
  • CC3D flight controller
  • 6” carbon propeller
  • Power distribution board
  • ImmersionRC TX
  • Nylon Spacers and M3 screws

First I mounted the M3 6mm nylon spacers on the top center plate. Next I mounted the MN2206 motors on the arms and cut the 2mm gold connectors as I was going to solder the motor cables directly to the ESCs.

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Then unsoldered the original motor cables from every ESC. I also removed the 5V and GND cables from 3 ESCs and left only the signal cable (I was going to use the supplied BEC on the fourth one).

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Took the bottom center plate and mounted the power distribution board with on it. Next step was cutting the power cables from the ESC, so these can fit on the bottom plate. Then soldered these cables to the power distribution board. I also soldered the power cable to the battery, the LEDs and a power cable for the ImmersionRC video transmitter.

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After that I put heat shrink on the ESCs and soldered the cables from the motors to every ESC. You should care when soldering to reverse two of the motor cables because of the different rotation.

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Next step is assembling the arms with the center plates. I don’t like to see the locknuts on the top, but it is much easier to mount the arms by that way. Once you are done with two of these, you can put the other screws from the top and then remove or reverse the firstly mounted screws and locknuts.IMG_9863IMG_9865

Finally I have mounted the CC3D flight controller, a carbon cover for it and the 6” propellers. I also put two 6mm nylon spacers in the middle between the two center plates for more strength. On the top of the flight controller cover I mounted the ImmersionRC TX with a zip tie until I receive my third FPV cover plate.IMG_9866IMG_9871IMG_9872

T-Motor MN1804 2400kv with 6045 propeller test

Posted by on May 18, 2015 No comments

I bought the T-Motor MN1804 2400kv for my SG Acro quadcopter about two months ago. It is something between the smallest T-Motor MT1306 and the bigger MN2206. Weight is only 16g. Most of the time I have used these motors on my quad with a 5×3 carbon propellers. Yesterday I decided to put 6045 plastic props and I was amazed. It flies much smoother and it is very quiet too. I was not sure if these small motors can handle 6” propellers on 3S battery, but that was not a problem. After an acro flight with lots of flips the motors were barely warm.

A bit more data: AUW is 335g with 3S 1300mAh battery. Copter hovers on about 33-35% throttle. Current is 5A at hover, which makes only 1,25A per motor. Achieved a 12min acro flight on 3S 1300mAh.

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DIY Bluetooth Telemetry Bridge for Pixhawk or APM

Posted by on April 19, 2015 No comments

I am using my HK Pilot32 (Pixhawk) since last year with my phone and DroidPlanner 2(now Tower). I have tested it as well with one HC-05 Bluetooth module as with 433Mhz Telemetry module. Using it with the Bluetooth module I don’t need to attach anything to my smartphone. But with the 433Mhz I have much better range. How can I get the great range without attaching something to the phone? Idea: using the 433Mhz telemetry module to transmit the data from the Pixhawk to the Bluetooth module and this one to my phone. Well I was not the first one with this idea, and I find a Bluetooth telemetry bridge from Event38. Looks good but the 150$ price is just too much in my opinion. So I decided to stick with my idea and made it by myself.

Parts needed:

Both the HC-05 Bluetooth module and the HM-TRP 433Mhz module work on 3.3V. But to use these with simple small 3.7V LiPo Battery, we need not the bare HC-05 Module. Take the one with integrated voltage regulator and pins already soldered (like the second or third one on the picture below).

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If you already have a 433Mhz Kit from 3DRobotics or HobbyKing you need to unsolder the HM-TRP module from the receiver module (the one with the USB Plug). Or as said you can buy only the bare HM-TRP module from Aliexpress. Download the datasheet for the module to check how it looks like and the pins descriptions.

What we need to do:

First both modules should use the same baud rate for communication. The standard for the 3DR Robotics module is 57600. So we need to change the baud rate for the Bluetooth module to be the same. You can check how to do this here.

Then take the 4 tiny cables and solder the pins from the HM-TRP module to the pins of the Bluetooth module as described:

  • 5V HM-TRP Module – 5V Bluetooth Module (before last Pin on the left side)
  • GND HM-TRP Module – GND Bluetooth Module (last Pin on the left side)
  • TX HM-TRP Module – RX Bluetooth Module (2 Pin on the left side)
  • RX HM-TRP Module – TX Bluetooth Module (1 Pin on the left side)

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A bit tricky was to solder the antenna to the tiny module. First you need to remove the plastic black cover. Cut the coax cable and remove the PVC shield. Then take the metal shielding and without cutting it, form it as a cable and solder it to the GND Pin of the HM-TRP module. The tiny cable under the shielding layer is the cable for the Antenna. Solder this one to the ANT Pin of the HM-TRP module.

That is all!

I used hot glue to place the HM-TRP 433Mhz module on the backside of the Bluetooth module, so it looks better and its more compact. Now you can connect the pins of the Bluetooth module to the battery and have your own Bluetooth Telemetry Bridge.

Change the baud rate of HC-05 Bluetooth module

Posted by on April 17, 2015 No comments

If you want to change some of the settings of your HC-05 Bluetooth module, like baud rate, password or the name of the Bluetooth module, you can do it easy and fast with your Arduino. I have done this to connect my Pixhawk to DroidPlanner over Bluetooth.

There are different HC-05 modules on the market, but it should work with all of them. On the picture below you can see a bare HC-05 module, 5V tolerant HC-05 module and 6V tolerant HC-05 module with a button. I prefer the last one, as the button makes the changing of the settings even easier.

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To change any settings of the module, it should be in the so called “AT Mode”. How to put the Bluetooth module in AT Mode: The “Key Pin” of the module should be set to “High”. This means we should apply voltage to this pin at the same time we power the module. On the last module, the button does this job. It should be pressed when powering the module with 5V. On the module without button, we need to supply 3.3V to the “Key Pin” when powering on.

Here is an example how to connect the module to the Arduino Nano v3. Note that there should be an jumper on GND and RST pin. By doing this, the Arduino will only act as a simple FTDI adapter.

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First connect the Arduino to the PC over USB. Then connect the cables in the following way:

  • TX Bluetooth –> TX Arduino
  • RX Bluetooth –> RX Arduino
  • GND Bluetooth –> GND Arduino

… and at last the 5V Bluetooth to 5V Arduino by keeping the button of the Bluetooth pressed. Or on the module without button, connect the Key Pin Bluetooth to 3.3V on Arduino.

If the HC-05 is in AT Mode, the red LED will blink at every 2 seconds.

Then start the PuTTY program (download link), configure the right COM Port (Check it in the Device Manger) and set the Baud Rate to 38400. This is the baud rate for AT Mode. Then click “Open”.

HC-05.over.PuTTY

In the newly opened black window type “AT”, press Enter and you should get “OK” as a result. Note that you want see what you type in the windows… Here some of the commands to change the settings you wish:

Change baud rate to 57600, 1 stop bit, 0 parity AT+UART=57600,1,0
Change module name AT+NAME=YOURNAME
Change pairing code AT+PSWD=0000

SG Acro – free quadcopter frame

Posted by on March 21, 2015 No comments

I wanted to share my new quadcopter frame design, that I made a few weeks ago in my free time. It is very light and compact frame, so it can be used for acro flying. The maximum propeller size is 6”. Motor to motor distance is 230mm.

For assemble are only needed 8 x M3x10 screws and 8 x M3 locknuts. Fully assembled the frame weight only 54g, as mine is made of carbon fiber.

I only had MN1804 from T-Motor so mounted these on the frame (weight 119g).  I think ideal should be the T-Motor MN2206 with 6×4.5 carbon propeller on 4S.

There are mounting holes for the most flight controllers, like the Naze32, OpenPilot CC3D, KK2.1.5 or Pixhawk. The mounting holes on the arms are standard M3 16×19, M2 16×12 and M2 12×12. I use the same arms on my new SG Adventure Mini v4 frame too.

It is as simple as possible, but with a good design. The CAD file is free. You can share it with your friends, use it to cut the frame for you, but not for commercial purposes. If you share it, please refer to this article.

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You can download the file here. If you like it, but don’t know anyone with CNC-machine, send me a message and I will try to help you.

24.03.2015: Assembled all the parts and here is how it looks like:

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Total weight without battery 201g. Share if you like it 😉

Update 18.04.2015: I equipped the small acro quad with Pixhawk, Neo M8N GPS and 433Mhz Telemetry module. There are some opinions that the Pixhawk is not so great as the Naze32 for acro flying, but for me as a beginner in Acro flying it is good enough. It is right that it feels not so “locked” as the Naze32. Now it is mini smart quad, not an acro quad 🙂

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Update 19.04.2015: Short flight with Pixhawk in Loiter mode (GPS is Ublox Neo M8N). ArduCopter version is 3.2.1. Compared to the old Ublox Neo 6M it is much more stable in my opinion.

Update 02.09.2015: Updated the CAD schematics for my SG Acro frame to v1.1. Added mounting holes for the flight controller of Nick Arsov, the AUAV-X2 as its holes are not the standard 30.5mmx30.5mm (yet). Also added spacers and design for Naze32 carbon cover. It fits to the CC3D flight controller too. If you like the design or have some other ideas, I would love to hear it.

Update 22.09.2015: Received the parts from the CNC factory and started building my new acro quadcopter. Here some details and pictures from the building process:

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Automatic proxy configuration in Chrome

Posted by on March 17, 2015 No comments

Sometimes there is a need to use a proxy server for a webpage, that cant be opened outside of a country. In my case there are few Bulgarian web pages like the vbox7 video portal. I don’t want to change my proxy settings every time I need to open that page, so I use an automatic proxy configuration in my current browser Chrome. This how-to works just fine with Firefox and Internet Explorer too.

Open the Settings tab in Chrome and click on “Show advanced settings…”. Now under “Network” click on the button “Change proxy settings…”.

Chrome.Network

You should see the window “Internet Properties”. It is actually the one from Internet Explorer. Click on “LAN Settings”.

LAN.Settings

In the newly opened window “Local Area Network (LAN) Settings” check the box “Use automatic configuration script” and enter this line: file:///C:/Chrome/proxy.pac

Now download the proxy.pac config script and copy it to C:\Chrome. If you want to place the file elsewhere, just change the line in the LAN Settings window.

The last step is to edit the proxy.pac file with simple editor like Notepad. Change the site you want to visit using a proxy and the settings for the proxy server itself like IP-Address and Port number and save changes.

That’s it.

Google Chrome does not offer to save passwords – fix

Posted by on March 17, 2015 No comments

I experienced an issue with Google Chrome in the past few weeks: it doesn’t offer to save passwords anymore, although under “Settings” the option to save passwords was checked:

ChromeSavePassword

I tried clearing the browsing data, resetting the settings and all kind of that stuff, but with no success. Even installing earlier versions of Chrome didn’t helped.

The only solution that worked was to delete two files from the Google Chrome Profile folder:

  • Login Data
  • Login Data-journal

Close the browser before deleting the files and after that start it again. It should be all fine now and Google Chrome should offer you to save your passwords.