Thursday, October 30, 2014

You gotta want it!

This one just resonates with me. You can ask my friends... I am often found saying the phrase "You Gotta Want It!" for just about any task in life no matter how big or how small. Because what is the point of doing something if you are not entirely behind it. Why half ass doing anything if you are not 100% sure that is what you want to be doing at that very moment. You have to believe that every step you are taking is for the betterment of yourself and those around you cause if not why are you doing it.

I know this is easier said than done but that's why i love this quote. Find what you want. Write it down. Then focus on that goal every single day. No matter how little or big. Work on it every single day. Its like investing. Putting a little bit away every day, even just a dollar, will turn into huge extraordinary results years down the road.

Anyone that graduated college in my opinion knows a little bit about this. You wrote down on your college admission essay why it was that you wanted to go to that school and why you want to graduate. Then you made a course plan, worked on it every single day, and you reaped the rewards 3-5 years later. A little taste of that shows just how powerful this concept can be.

I will continue to make goals for myself that I identify as true inner targets and make my life and others lives better. I will work on them every single day.

Thursday, October 23, 2014

Testing Hall effects

Today's test work was pretty simple overall. After having installed the hall effect sensors onto the motor I wanted to test to see if they would in fact work. One issue I was afraid of was that the rotor magnets did not go down far enough past the stator to trigger the sensors. The sensors were just below the stator windings because the slots in the stators in addition to the windings were not big enough. I was also not sure how the latching function of the Melexis US1881 was going to work.

1. Wiring up the sensors

First thing I needed to do was to run some wire from the TO-92 package Hall effect sensors glued to the stator to a breadboard or test apparatus. I had some old computer fan power cables lying around (the ones that plug into the mother board) and they seemed like they would do the trick just fine. I cut one end off and left the female connector end on.

Fan wires attached to sensors

Gate drivers and Hall effect sensors

Today I accomplished two main things. The first was quite simple. I was able to get the gate driver IC's mounted to the SOIC-8 to DIP-8 breakout boards from sparkfun. The second was to determine where to place the hall effect sensors to meet the needs of the controller as well as find a convenient place to place them physically.

1. Gate Driver SOIC to DIP

SOIC-8 to DIP-8 breakout board

Top view of the Sparkfun breakout board.

Wednesday, October 22, 2014

First Parts Came In!


My first order of parts came in today. I am starting with the basics for right now. My goal is to get a BLDC motor driver up and running for 1 motor with the same MCU that will be used on the GatorQuad, and then go from there. This will allow me to start to prove the concept while saving as much of my code and work moving forward.

Parts Ordered:

  • 6 x CSD18537NKCS - N Channel Power Mosfet - Texas Instruments (Digi-key, TI free samples)
  • 3 x FAN7842MX - High side, Low side, Mosfet driver - Fairchild Semiconductor (Digi-key)
  • 3 x US1881 - Hall effect latching sensor, Melexis (Sparkfun)
  • 3 x SOIC to DIP adapter 8-pin, Sparkfun (Sparkfun)
  • 1 x NTG Propdrive 28-30s 800kV BLDC motor, Turnigy (Hobby King)
  • 1 x 3.5mm 3 wire Bullet wire connectors, Hobby King (Hobby King)
  • Already on Hand:
  • 1 x XMOS startKIT multicore microcontroller, XMOS (XMOS)

The motor was ordered from Hobby King because it was inexpensive and widely used. I did not know what I was getting with it because It's Hong Kong manufacturer "Turnigy" does not have a lot of documentation online. This motor does not come with built in Hall effect Sensors for sensored control. I ordered a few bullet style connectors from HobbyKing so i can make and connect my own wire. Thus I ordered some from Sparkfun and hope they will fit my needs. I did not notice when I ordered the Hall effect sensors that they are a latching version, so I will find out if that will effect my control and ultimately may need to order non latching sensors. The TI Power mosfets are capable of sourcing 50A of drain current while the motor is only rated for 20A. Obviously I way over sized here, these will likely be scaled down in later designs, but for now I wanted to be on the safe side. Picking the gate drivers was a little tricky, the main things that I wanted was independent control of the High side and Low side of an H-bridge, as well as enough source current to switch the mosfets fast enough. I found scattered resources across the web to help with determining the source current for certain mosfet capacitance's and switching speeds. Right now I think I am okay, If my calculations were wrong we will revisit this. The gate drivers were a small SOIC package and I am doing my initial prototyping from a breadboard and desktop power supply. Additionally I will be using my Xmos StartKit development board, so no self designed PCB's yet.


"Education is the most powerful weapon which you can use to change the world." - Nelson Mandela

I love Nelson Mandela quotes and all of the lessons that he had to offer. But more importantly one of the values I have fortunately been exposed to in my life is education. My parents taught me at a young age what an education can do for oneself, and later on in college I truly was able to live that.

Through my own experiences and the teachings of those who were kind enough to share, education will remain a high priority in my life. With a desire to learn all else can be accomplished, all goals achieved, and all problems quelled. All great things come back to the desire to learn and to get better. 

I will continue focusing on my continuing education, as well as spreading the gift to others.  

About this Blog

Intrinsic Motivation

The motivation for creating this blog is pretty simple. I want (and need) a place for me to dump my thoughts and ideas pertaining to projects and self learning that I am working on. I often find myself doing many things like projects, reading, learning, and self improvement routines to continue my own personal development as I navigate life. However as much as I start these projects and goals, I often find myself getting lost along the way. Whether it is due to my own laziness or because what I had started had gotten so off track I forgot what I was doing or why I was doing it in the first place.

I plan to mainly use this blog as a project log for various things I may be working on. I am an electrical engineer by trade so I will likely be working on something in that field. This will allow me to have one place to post pictures, ideas, sketches, and logs... and hopefully keep me on track along the way. Also what is equally important is that this will be a venue for people to comment on my projects and goals. Maybe to motivate, provide input, point me in the right direction, or constructively criticize, whatever the reasoning the value of peer discussion can not be overlooked.

This blog (I hope) will be what leads me from starting things and maybe getting lost along the way, to staying on track. Goals can be dynamic and I hope that this blog is proof of that, but staying focused on the moving target is what is difficult. The motivation for creating this blog is pretty simple, the motivation is purely intrinsic.