BYOAQ-BAT I: Introduction

I’ve been slowly collecting parts for a new quadcopter – by slowly, I mean for over a year; each time I spot something better designed, I’ve been buying them – for me design incorporates not just engineering  but also elegance.  I finally have all the parts I need to start building, and since I’m starting from scratch, I thought it worth blogging my progress – “Build Your Own Autonomous Quadcopter – BOM (Bill of Materials), Assembly and Testing.  You can follow my progress by searching for the tag “BYOAQ-BAT”.

WARNING: This series of articles describes how I am putting together my new autonomous quadcopter.  They are not a set of instructions which, if followed, will result in a working, remote controlled quadcopter.  They won’t.  What you will end up with is a piece of machinery that spins blades around all by itself hacking to pieces anything in its path.  I have deliberately omitted the very low level details from this set of articles for that reason.  If you do choose to use these articles as though there were a set of detailed instructions, any resultant damage, death or destruction is entirely your own fault.  You have been warned.   

On the flip side, if you are building your own quadcopter, with either autonomous or human control, I hope you’ll find things here that are interesting and useful to you.

First, PCBs and electronic components.  Here’s the PCB, as produced by Ragworm from the Eagle beret.brd board file up on GitHub.  It’s essentially just a breadboard, with just a few minor tweaks to fit some very specific requirements of my new quadcopter.

Beret PCB top

Beret PCB top

Beret PCB bottom

Beret PCB bottom

When soldering components to PCBs, I find it’s best if you add the smallest things first, and build upwards.  The first step then is to add the wires; I’d worked out the wiring beforehand on a print out of the top-side of the Eagle board.  With all the wires in place, I sellotape them down before flipping the board and soldering them to the board.

Beret wiring

Beret wiring

Once the wires are soldered in place, next step is to add the smaller components – this time I hold them in place with blue-tak while I solder them on:

  • a 100k pull down resistor
  • a MOSFET
  • IDT pins for the IMU breakout
  • IDT pins for the ESC connections

Next comes the 40 pin IDC connector joining it to the PCB.  At this stage, I fix the beret HAT board PCB to the A+ (no power and no SD card) while soldering on the connector to ensure positioning is perfect.

Next step is to add the wires and connector that will eventually attach to the heater resistor.  It should now look like below.  All that’s missing is the IMU; but before I attach that, I like to test the various points on the board.  Without an SD card, you can power up your A+ with the beret plugged in and then power will make it through the GPIO pins to the PCB to allow you to do the testing with a multimeter.  I check that there’s 5V where I expect it, and zero resistance between connected rows / columns where I expect.

Beret sans IMU

Beret sans IMU

Prior to attaching the IMU to the pins on the PCB, there’s a few bits and bobs to do with the IMU breakout board.  It supports both I2C and SPI, and allow option pull-up resistors to be used, and if using I2C, the I2C addresses may be selected.  These are all done by soldering bridges between clearly marked contacts on the breakout PCB.  Since the Raspberry Pi I2C pins already have pull ups, I’ve not bridged the gap enabling the breakout pull-up.  I’ve set both I2C solder ‘bridges’ to 0.

I attached the 10Ω SMD resistor “heating element”, gluing it to the top of the IMU with Arctic Silver thermal epoxy adhesive*; I couldn’t find a UK vendor so bought it from the US via e-bay.  Once the epoxy has set (I give it a good couple of hours to be sure), I soldered on a couple of IDT pins to the resistor.  Finally, I surround the IMU with a wrapping of blue-tak pure to provide thermal insulation.

Now I can attach the DroTek 10DOF IMU itself to the PCB IDT pins already soldered onto the board.  And that’s it:

Beret complete

Beret complete

The next article will cover getting the A+ and beret firmly attached to each other and to a base which are all aligned / parallel to each other.

*This is the stuff used by psychotic overclockers on gaming machines along with water-based CPU cooling etc etc.

16 thoughts on “BYOAQ-BAT I: Introduction

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  8. I read this article and i have one big question

    What did you do and why??
    U see me and my friends are completely devoted on doing this projects and frankly we know very little in this area but are willing to learn. Your help will be grateful. Thank You

    • This series of BYOAQ-BAT describes what I did. Why did I do it? Because it looked interesting and challenging. When I started I knew nothing too, but over time, as I tried lots of things, I’ve learnt everything by myself, and that made it more satisfying.

      Read the code from GitHub/PiStuffing/Quadcopter: I’ve put lots of comments in there explaining what each piece of code is doing and why.

      Myy advise: don’t be a learner, be an explorer. Working it out for yourselves is so much more interesting than just been spoon fed information.

      Good luck.

  9. Hi andy,

    I’d like to ask if PI will be suitable for our final project, Our final project is a self-stabilize and altitude control airship (blimp). We will be using smartphone sensors(barometer,gyro,accelerometer and magnetometer for the heading) thru bluetooth communication. In addition, we will implement Fuzzy Logic Controller for the algorithm of the airship. Would you recommend PI for this kind of project or would suggest another way instead?.Thanks for the reply. It will be much appreciated. Thanks andy .

    • Yes, a Pi would work well for that; the only real alternative is an arduino, but there are so many advantages of using the Pi because it’s running a proper operating system with a file system.

  10. i like your project “Semi-autonomous quad-copter”. i am networking student and searching topic for my final year project and i find your topic nice and interesting and want to do project.
    I want to know what material is required to built this project and what operating and programming tool you used in this project and it is network related.
    i’ll be waiting for your reply


    • Hi Aryan,

      This projected runs on a Raspberry Pi computer, running Raspian / Debian Linux OS; the code is written in Python. Unfortunately for you, there’s nothing about networking in the project. I just log into the quad from another machine to start up or kill the flight controller program.

      To me it doesn’t seem suitable for you networking project.

      Good luck!


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