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Trent's Blog

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A few years ago, I underwent a surgical procedure called a Spinal Fusion. Afterwards a special medical device was prescribed to assist with the fusion process. This device is called a Combined Magnetic Field Bone Growth Stimulator.


The little kid in me has been eager to see the inner workings of this device. It was only a matter of time before it would be taken apart.


Here are some photos of what was found inside.




Device Description


The SpinaLogic® bone growth stimulator (DJO, Vista, CA) consists of a three-dimensional patient interface contoured to follow the curvature of the lumbar spine, a control box containing the electronics, and a battery pack . The device is used for 30 consecutive minutes a day until fusion occurs as determined by the treating physician. The patient interface consists of a single transducer coil to generate the magnetic field and a magnetoresistive element to provide feedback as to the magnitude of the earth’s magnetic field which ranges from 25 to 65 microTesla (μT). The coil is constructed using 504 turns of 30-gauge copper magnetic wire.


When the specified current is applied to the coil, it generates an extremely low-frequency and extremely low-intensity magnetic field that has both alternating and direct current (AC and DC) components, labelled a combined magnetic field (CMF). Specifically, the field oscillates sinusoidally at a frequency of 76.6 Hertz with an AC component of 40.0 ± 8.0 μT, peak to peak, and a DC component of 20.0 ± 2.0 μT.


The source for this information.


               First Test of EDF Jet Motor Prototype


This is a scaled-down working model of an Electric Ducted Fan Jet Motor with Thrust Vectoring control surfaces. I constructed it out of 5mm Foam Board typically found in the arts & crafts section of local store, poster board, white Duck brand Duct Tape, hot glue, and a modified cooling fan recovered from an Original Xbox gaming console. The purpose of making this model was first and foremost to see if it would actually work. I am working on a project that uses EDF Units and Brushless Inner-running motors as a method of propulsion. Before I invested in a factory made EDF Unit and motor, I thought it would be best to construct this prototype for testing. This fan is not powerful enough to provide the thrust needed for my project. It is merely a means to test the Thrust Vectoring control surfaces.

This prototype was designed with a compass, square, and metric ruler, remnants of my days in mechanical drawing class.


                What is Thrust Vectoring?


Thrust vectoring, also thrust vector control or TVC, is the ability of an aircraft, rocket, or other vehicle to manipulate the direction of the thrust from its engine(s) or motor(s) in order to control the attitude or angular velocity of the vehicle.


For aircraft, the method was originally envisaged to provide upward vertical thrust as a means to give aircraft vertical (VTOL) or short (STOL) takeoff and landing ability. Subsequently, it was realized that using vectored thrust in combat situations enabled aircraft to perform various maneuvers not available to conventional-engined planes. To perform turns, aircraft that use no thrust vectoring must rely on aerodynamic control surfaces only, such as ailerons or elevator; craft with vectoring must still use control surfaces, but to a lesser extent. - From Wikipedia, the free encyclopedia 









The design of an EDF unit has to be exact. If the circumference of the duct is not perfectly circular, this can cause a decrease in thrust and possibly fan blade and/or EDF unit failure. The purpose of these video tests were to see if the fan blades would make contact with the duct and to see any vibrations. I used an E-cigarette for the smoke test, so I should have said vapor test.


      The solar corona at the March 2015 total eclipse over Svalbard. Photo: Judy Anderson. Processing: Alson Wong.



Warning! Even if 99% of the sun is covered by the moon, the remaining 1% crescent is dangerous to view with the naked eye and can cause serious eye damage or blindness. For information on safely veiwing and photographing an eclipse, please refer to the following links.


     How to Photograph a Solar Eclipse from Nikon


     How to Photograph Total Solar Eclipse 2017 - How to Take Pictures of the Sun


How can I photograph a total solar eclipse?


You will need to purchase a solar filter that will reduce the brightness of the sun so that the light intensity does not  destroy your camera. If you ONLY take a photo at the moment of totality, you will not need this filter, and will be rewarded by being able to photograph the faint corona, which will not be visible if you have the filter in place. Most digital cameras with telephoto lenses of 100 mm or larger will show a disk for the eclipse that will show some detail. As a trial, photograph the full moon at night. It will be the same diameter as the total eclipse, so you can practice on the moon first to get the right telephoto lens combination. There are many places on the internet where you can get detailed information such as Mr. Eclipse







The following links contain information with regards to the Solar Eclipse of 2017. There are many resources such as high resolution maps, Tracking Software Apps for Smartphones, 2D/3D Printable Pinhole Projectors, veiwing safety tips and much more available from .


My Photos of the 2017 Solar Eclipse


These images were photographed with binoculars, solar filter film removed from disposable solar eclipse viewing glasses, and an android smartphone.

I originally constructed an adapter with the solar filter for the Raspberry Pi Camera but it failed a few hours beforehand. I did use a Pi 3 with display to watch the live stream provided by NASA.  At one point the ISS passed in front of the Sun and was visible with binoculars for a brief moment. I was lucky enough to witness this but unfortunately was unable to capture an image of this rare occurrence. I apologize for the quality of the images, my equipment was improvised.










This was one of the best of many images. Afterwards I lost the proper alignment between the binoculars and camera lense.




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           "Get it to his desk quick quickly! We can't afford to lose any more Stormtroopers."


Project Iron Pi Zero Mark II



I recently purchased the Pimoroni EnviroPHAT and Adafruit PiOLED display for use with the Raspberry Pi Zero v1.3. I currently have the EnviroPHAT and PiOLED display connected to the RPi Zero and the Zero4U 4 Port USB Hub with the Pimoroni Mini Black Hat Hacker. Here are a few images of everything connected. I access the RPi remotely with SSH via WiFi. In the captured images I have the RPi Zero powered with the Adafruit PowerBoost 1000C and LiPo battery. There is also a USB Voltage Meter with OLED Display to monitor the power consumption.


These images and video were captured with a Xbox 360 Live Vision Camera I found at a used video game shop. I will explain in another post how to configure a Raspberry Pi 3 for use  with this specific Microsoft Live Vision Camera.



           With only the PiOLED, Zero4U, and Wifi Dongle connected to the RPi Zero



        And now with the EnviroPHAT, PiOLED, and Mini Black Hat Hack3r with moderate cpu usage during apt-get update && upgrade



        Let's see those LEDs ! Show me the OLED!!



                               * Legos not included



After making some modifcatitons to my primary everyday camera (removing the scratched protective lens from my mobile phone's aging but useful 5MP camera)


Before with damaged protective lense cover, photos would have a cloudy appearance and unnatural artifacts in captured images.


And now the quality of the camera sensor can shine. Get back to work.



Let's have a closer look at the Adafruit PiOLED  display and the Pimoroni EnviroPHAT under better photographic conditions.



The Raspberry Pi 3 and Raspberry Pi Foundation 7" Touchscreen in a SmartiPi Case is my favorite. By using SSH we can update, upgrade and install necessary software with the Wifi USB Dongle. Important note, purchase Wifi USB Dongle from source that has confirmed the dongle is compatible with Raspbian.



Installing the Zero4U 4-Port Hub is very simple. It attaches to the RPi Zero with included 4 poly screws,spacers, and nuts. The Zero4U is powered via 4 gold pogo pins that contact with PP1 and PP6 for power, and PP22 and PP23 contact pinouts located on the bottom side of the Pi Zero. When the RPi Zero W was released, the makers of the Zero4U released an important hardware update which is the of the addition of a special ferrite ring to protect the PP22 and PP23  connected data carrying pogo pins from unwanted RF interference. This specific ferrite ring has been made available for purchase by the manufacturer for customers who purchased the Zero4U before the Pi Zero W was released.



The Pimoroni Mini Black HAT Hack3r GPIO Breakout Board is very helpful in testing multiple Pi Zero HATs as long as there are no conflicts in pin usage.



Power is supplied with the Adafruit PowerBoost 1000C and a 3.7v 2500 mAh Lithium Ion Polymer Battery Pack in a protective case made from foam board, recycled foam packing material and Duck Tape.



Here is a nice close up of the new Adafruit PiOLED with its tiny yet highly visible OLED display. I have not removed the protective film yet.



The Pi OLED retains visability and clearity in various lighting conditions. The Dual RGB LEDS of the Pimoroni EnviroPHAT become visible after I decrease the amount of ambient light in my office.






Here are links for where these items may be purchased.


  Authorized Adafruit Industries Distributor | Newark element14


I am currently working on Python code and in my next update I will be attaching a Raspberry Pi 8MP Camera v2.


Thank you for checking out my blog. Stay tuned for updates on this and other projects I am working on.


Trent Pfeiffer

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  I am not a former actor who played the part of one of the coolest cyborgs and later went on serve as Governor of California as exciting as that sounds.




June 9th, one year ago I underwent a surgical procedure to repair severe damage of my vertebrae and spinal cord. Yesterday I had my final appointment with the doctor who performed this very risky operation. He informed me that the procedure was a success.


    It felt so great to stand in front of the doctor,  shake his hand, and thank him for saving the use of my legs. In the six hours that this man worked on my body, he has given me a major part of my life back.


     Here are a few X-Ray Images of the procedure. Imaging such as this is usaully available to the patient minutes after captured thanks to cloud networking and digital media. These images are from a CD that was provided to me by the Imaging Technician at no cost. The CD actually came with live software used to view the various forms of imaging such as MRI, Ultrasound and Xray that was used in this procedure.


Warning! The following X-Ray images are of a medical procedure and might not be suitable for all audiences. Viewer discretion is advised.



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    PFEIFFER TRENT xray.jpg





I also have some nice hardware in one of my legs from two years ago.




    And back in October of 2008 I sustained a skull fracture and brain injury that caused about 9 months paralysis of the right side of my body. With physical and speech therapy I was able to recover. When technology and medicine come together, the effects are truly amazing.


I am not the Terminator or Wolverine, as cool as that would be. But I do have more more screws than a iPhone.





Unboxing  the   Beaglebone  Black  Wireless 


      I would  like  to  start by  thanking  the  Element  14  community  for allowing  me  the  privilege  of participation  in  the  testing  and review  of this  product . It is my intention  to  provide  an informative  review  of  the  BBB  Wireless  for  you, the  reader. I hope  that  you will  find  this report  helpful  and thank  you  for  your  time reading  it. Okay  let's  get   started. It is with  great  honor  I present  to you, the Beaglebone  Black  Wireless.


      The BBB Wireless  arrived  from  Newark  Element  14 on time  as promised. It was found securely  packaged and intact upon  opening  of box. Packaging  is   of good  quality  with  Newark  Element  14 website  printed on  box. Inside  the   box  protected with  recyclable  packing  paper  and pink antistatic  bubble  wrap  is the  box containing  the  BBB  Wireless  and some  documentation  from  Element  14. The  box containing  the  BBB W is of very  good  quality. Glossy  printed color  image  of device  on box, on reverse some  information   about  the  device  and country  of  origin which  is  Madison Heights, Michigan,USA.


     Inside  the  box  I found  a printed  card from containing easy to follow  instructions  for  the  first  boot. On the  reverse  of card are found   two different  methods  of getting  started  with  the  device. The first  option  is “Tethered  to  a PC” and the  directions are as follows:

  1. Connect the  USB cable  to the  board
  2. Connect  the  other  end  of  the  USB  cable  to  the  PC
  3. Look  for  a  new  mass storage  drive  to appear  on  PC
  4. Open the  drive  and click  on START.HTM
  5. Follow  the  instructions  on the  PC


    And  the  second  option  is  “Stand alone  Beaglebone  Black”. Here  are  the  directions  as listed. I would  like  to  mention  that  this method  will  require  peripherals  not  included  with  the  board. They  are  an USB  keyboard  and  mouse, an USB  hub, a HDMI  TYPE  A  to  HDMI MICRO   TYPE  D  cable, and  a 5V  1A  DC Power  Supply with  a  2.1mm ID x 5.5mm OD Coaxial DC Barrel Plug all of  which  are  available  from  Newark Element  14  and  Premier  Farnell  Element  14. The  start up  guide  states a 5V 1A DC power  supply  but  the  Adafruit  power supply  that  is  listed  on  Newark  as being  associated  with  the  BBB  Wireless  is a 5V  2A  DC Switching  Power  Supply with  US 2 prong Plug. If purchasing  for   use  in  another   country, you  will  need  to  get  a  5V 1A DC power  supply  with  that  country's  power  plug. I believe  that  the  2A version  is safe  to  use  as with   the  recent  addition  of  the new wireless  chip and any  USB  peripherals connected, the  1A might  not  be sufficient anymore. This  is  just  an assumption  and  I   will  refer to  to clarify what  exact  specs are required. I was able  to  download  the  Beaglebone  Black System  Reference  Manual from  the  site  but  I was not  able  to  find a  specific  manual  for  the  Wireless  version yet. The  supplier  might  be  in the  process  of  creating  a revised  copy  with  the recent  hardware updates. If  you  have  the  necessary  peripherals  to get started  with  the  stand alone  Beaglebone  then here  are  the  simple  instructions  for  that method as stated in provided  quick  start guide.

  1. Connect the keyboard/mouse to the USB Host port
  2. Connect  the  HDMI  cable  to the  board 
  3. Connect  the  HDMI  cable  to  the  HDMI  monitor 
  4. Plug  in  a 5V  1A  DC  power  supply 
  5. Board  will  boot without  password 
  6. Desktop  will  appear  on  the  monitor 


      I am  about  to  purchase  a HDMI  TYPE  A  to  HDMI  MICRO  TYPE  D  cable  and  a 5V 1A  DC  power  supply  to test  the   BBB  Wireless in the  second  method  but  in the  meantime  I will  be   performing  what  tests  I can  with a  PC.



Nice package, easy to tell who it came fromAgain very nice packaging. Made in the USFirst thing found is card from Beagleboard containing easy to understand instructions for getting started with your new BBB-WEasy to understand instructions provided for two different ways to get started quickUSB cable comes with BBB-W for connecting to PC and can be powered via USB alsoStandard Anti Static packageVery nice silkscreen. Easy to read print. DSC_0708.JPGDSC_0722.JPGDSC_0721.JPGDSC_0720.JPGDSC_0719.JPGDSC_0717.JPGDSC_0716.JPGDSC_0715.JPGDSC_0709.JPGDSC_0708.JPG