Stop Time

Schindler Engineering will be off-line for everything except for Mission Critical Activities for the next couple of weeks.

If you are planning an emergency…  please try to make it land at least a few weeks in the future (that’s a joke…  tho not too funny I admit…  depending on your perspective)


-the management

Schindler Engineering Adventure 003

It was noted by staff that it has been a Looooong time since we have gone on a Schindler Engineering Adventure…

(not really – it has just been a long time since we Posted about it…  )

So – here we go:      Cliff Clambering at Sunset, a Silent Movie

Of course Kimberly had her clamber as well…  so our next silent movie will star her and we are thinking the title will be:

“Treasure Hunting in the Sketchiest Spot Imaginable…  During a Storm Surge”

That about sums it up.

Until next time…  we are super busy…  but we always make time for exercise, and we only do exercise which is fun.

Why    would    anyone    do    exercise    that    is    miserable   ???

Solve that riddle and staying fit gets easy.


Current Loading

Sorry, no fun pictures of outings to post…  tho the waves have picked up here in Santa Cruz.

Contract work picked up a bit too.  In the immediate we are pretty committed…  but always on the lookout for FTE and LabVIEW work.

  • 10hrs/week – OEM Automotive in Fremont (Startup)
  • 10hrs/week – R&D / Sevcon support in La Selva Beach (Startup)
  • 1-10hrs/week – Robotics in Palo Alto (Startup)
  • 5hrs/week – LabVIEW  (YEA!!!!!)

Our stated intent is still to move toward FTE work (in any field) or LabVIEW work (of any kind be that FTE, Retainer, Contract, Consult, or in Education).


-the management

To the prospective Full Time Employer

I am currently seeking full time employment, in the following order of preference:

  • Test Engineering in a position that is heavy in LabView.
    • R&D, Lab Support/Management/Tooling, Qualification, Production testing, component -> PCB -> System level.  If it involves solving problems with LabView I am in.
  • Full Stack Battery Management Systems Engineering
    • Architecting, down selection, component spec’ing, circuit design, PCB layout, proof of concept and first runs, production intent hardware, full production, legacy support, retrofit, and reverse engineering.
  • Systems Engineering in the Electric Vehicle market or DC of any kind
    • Battery powered systems low power to high power.

Schindler Engineering   is not currently    committed to any long term efforts which can not be tied up inside of a week.  We have a few short term deliverables which are at 90% and we are hesitant to make further comittments before investigating opportunities to work under the umbrella of a larger company.

“We” (Schindler Engineering) are currently only responsible to myself and our Accountant.  Our accountant has opportunities for FTE work and our contracting associates are all pretty well placed in paying work off site.


Rational for seeking Full Time Work:

Contracting and Consulting affords us a lot of flexibility…  but it comes with a very large overhead, inconsistent finances, and most importantly a risk level which is above what we can currently tolerate.  We have financial obligations and stability needs which are incompatible with the ups and downs of Startup Life.

I am in a position to commit to FTE work for a length of time up to 10 years and I would prefer to target positions which will last no less than 2 years.  Of course life happens…  but we always aim at what we want to hit.

I can work On Site anywhere in the Bay Area 40hrs a week with On-Call from Santa Cruz County (40 minute response time other than rush hour).

I am flexible around compensation depending on requirements.  If I need to be on site, on a fixed schedule, on hard deadlines, doing tough work, managing risk, <[in the critical path…]> then I need to earn market rates.  If on the other hand…  there is flexibility for me to work an alternative schedule, work from home part time, to work outside of the critical path, to do work which involves low stress/low risk…  we can afford to work a bit under market.  The key factor in salary requirements is how tied into the schedule I am and how much flexibility there is for my family needs.

At this point in my career I should be transitioning into management… (which is as critical path as it gets…) but I still really enjoy engineering work (which often can involve parallel path activities…) so I will entertain any opportunity for the right company.

You will start to see a transition in the Schindler Engineering blog to focus more on LabView, Test Engineering, BMS architecting, and other activities which develop quickly (meaning I need to stay up to date on the latest to be relevant).

Feel Free to check in on some highlights of my experience at LinkedIn:

Being that I have over 15 years post bachelor experience…  there is far more unlisted than listed at this point.

thanks,   -Patrick

Kayak Power….  V2 in the water

Last night (after sunset) we were able to breach the harbor mouth under new power.

In the pics you can see the vintage Minn Kota that powered V1.  Tiny motor, tiny prop.  Next to that is a big upgrade courteously of a Masterguide bow mount.

(note:  I apologize for the pictures.  My Nexus 5X is finally giving up the ghost after a very hard life.  It was an excellent phone.)

Both of those motors are 12V rated…  but obviously the one on the right is capable of putting on a better performance.

We picked up a bow mount Masterguide (remote control steering and all) for $26 at the Fleamarket.  It had a bad steering gear box and trouble with the PCB board.

No problem…  all we wanted was the lower unit.  We disassembled it, along with the vintage Minn Kota, and put something new together.  The Minn Kota donated only the mounting hardware.  Control is handled by a 300A AXE controller.

This is a progress pic (of course that stuff needs to be ocean resistant…) but in it you can see the basic layout:

Battery:  6S 6P 35C Hobby King packs.  This works out to 22.2V @ 18Ah so capable of 20KW burst and almost 1kA.

Controller:  AXE 300A controller capable of 16V to 60V…  so Ebike battery compatible.

Throttle:  Zero pulldown 5K Magura.  Note that you need to configure this to run 5K to 0K (to avoid WOT on a disconnected throttle) and be sure to enable the interlock on startup (wont run until it sees 0% on the throttle).  Take your time with the Magura and make sure you get a clean 5Kohms to 0ohms…  they can be calibrated and many people change the output range to match a standard 1.2V to 4.2V hall throttle.

Wiring:  Coming out of the lower unit were 4 wires…  the heavy RED and BLACK are direct motor connections.  The Green and Blue can be ignored as they go to a mosfet pack that we wont be using.  (The AXE controller handles all our PWM needs)

We connectorized everything up with Anderson PP45’s in parallel (2P can handle 100A continuous into 10AWG) and SB120’s…  which are rated for 240A @ 600V.  Balance taps are paralleled at the cell level using MethTek parallel boards.  Currently there is no BMS in the system, we are working on that.

As a rule of thumb…  doubling voltage quadruples power.  In this case we doubled voltage and sized up the prop considerably…  leading to a huge performance increase.  The speed and acceleration is night and day.  We will grab some GoPro video some time this week.

V3 will be a Gen 4 Sevcon along with a 75-7…  but that adds all sorts of complexity that we are not in a position to tackle yet.  Prop angle, waterproofing, steering….


Sevcon Gen 4 Support

We are to the point where we can offer professional Sevcon Gen 4 support.

We have invested over a year into the minutia of this.  I dont want to make it sound complicated (because we can simplify it for you) but working with Sevcon hardware really does require professional support unless you are in a position to tool up, learn the tools, and invest the time.

We have an OEM relationship with Sevcon.

We have up to date licensed copies of DVT.

We can load DLD files.

We can read, modify, and write DCF files.

We can help you to transition your existing system from a Size 4 controller over to a Size 6 controller (for significant performance gains).

We can support you with Sin/Cos encoders, UVW encoders, wiring and pin mapping, basic tuning, and some Dyno tuning where appropriate.

We have a line of custom harnesses built to or above OEM Automotive spec that (in combination with a DCF tuned to your hardware set) can make for a turn-key setup.

We can support any existing Zero Motorcycles gear as well as any equipment purchased from  We are working on supporting other existing motors like those found at Joby, Jozztek, and others.

We would like to support Boating applications, Kart applications, custom Motorcycle and Enclosed medium weight EV applications.  We are even starting to support some E-Flight applications (tho those require a higher level or rigor to assure air safety).

Currently we are working under the umbrella of an OEM as we develop a new Power Systems branch.  Until that venture is funded this is somewhat grass roots.

Hourly consultation is available – either over the phone or email.  Email is suggested as it tends to be more productive.  If you can clearly state what you have, where you are at, and where you want to go…  we can make suggestions as to other OEM’s and niche shops we work with.

We can suggest parts for safety and reliability (like throttles with interlocks) and inform you as to what you will need if you want to support yourself… or we can steer you toward one of our turn-key options

The key tools are:

  • Recent version of DVT
  • Proper galvanically isolated CAN programming device (IXXAT or Clone)
  • Professional 2 step crimpers and pins for Sevcon 35pin connector
  • Appropriate hall sensor and means to calibrate to motor
  • Harnessing and matching DCF

If you are looking for a turn-key solution…  or just looking for some help mastering what you already have, we are available.

At the moment we are working on a custom version of the ClearView iterface that will alleviate the need for DVT and an IXXAT such that customers can collect data and make minor changes without having to loop us in.

Feel free to reach out to us in the Contacts section.

All due respect to those who came before us like Ryan Biffard of Zero Motorcycles, the team at Thunderstruck-EV for their work supporting Sevcon, Steve at Jozztek in the UK for his EV expertise, and all the others who helped get us to where we are at.

Respect also to the companies where I have worked that first introduced me to Sevcon gear in their products – namely Zero Motorcycles and Electric Movement.



Schindler Engineering Adventure 002

This adventure has been all about BOATING!

Since we moved closer to the sea (we are a block from the harbor small-craft launch now…) interests have shifted to powered water craft.  Where we are ultimately headed is a Zero Motorcycles 75-7 driven by a Sevcon Gen 4 in size 6…  but before we jump into that we had to freshen up on some basics.

Here is a pic of the Size 6 Sevcon with a custom harness that we spec’ed and built from scratch over at Calfee Design

Of course that all gets split-sleeve for abrasion and overall aesthetic but you get the idea.

The motor will look a little something like this:

That is an up-cycled Zero motor that has been carbon wrapped on a lathe and drilled for ventilation.  That particular motor has an interesting future …  ours will be a bit different.



The Transom is the mounting point on your boat for the motor.  In this case…  a small electric outboard you will recognize as a “Trolling Motor”.  These motors can be quite over-volt friendly…

You will notice that is a REALLY ROUGHED OUT example.  We built this from no plans in 45 minutes using nothing but some cabinet wood we found in the garage, an angle grinder (no saw!), and a drill.

The assembly mates to the plastic Kayak via blind rubber nuts…  you basically over drill, insert, and expand.  They work quite well and do not damage the kayak in the process.

In the spirit of ROUGHING OUT A PROOF OF CONCEPT we picked that Trolling motor up for free in Laselva, nabbed the battery out of my car, and headed for the harbor for a test run.


Testing, testing, testing…  I cant say it enough!

At Schindler Engineering – before we dive head first into an expensive venture we spend AT LEAST 20% or 30% of our time bounding the problem.  We start simple and cheap…  with a test that will help us understand what sort of hurtles we will see as we start to scale.

If the 2 person Kayak is hard to handle on 30lbs of thrust…  it will be unmanageable with 300lbs.  🙂   Seems obvious, but you would be surprised at how often we have seen a system getting finishing touches that fundamentally just will not function well.

So with the boat in the water and a better understanding of how it will load down under the weight, how the steering will feel, whether it will need stabilization…  we decided further testing was in order.

Off to Washington…  our official test site for all things ridiculous.

Here is a shot of our test fleet:

The Trusty Aluminum cruiser, the not so trusty foam floater, and the ultralight inflatable.

For the record…  the foam bit of business up there was built by Mathew R. back around 2013.  We were on holiday and I challenged him to make a seaworthy vessel in less than 15 minutes.  That’s what he came up with… quite clever…  and so as soon as he announced completion I tied a rope to it, asked him to board, and took off across the canal!  Lol…  We motored until the battery died and then I rowed him back in.  Confirmed…  his vessel was indeed seaworthy.


Weight and draft is everything…  followed closely by steering and the ability to stay afloat.  This fine vehicle can be hand carried with ease but is hell to steer.  Right off it is clear that we will need a boat which is not flat bottom if we are going to harness the Zero Power Train…

It needs to be light…  it needs to hydroplane to some degree…  it needs to turn on a dime WITHOUT FLIPPING.  (Reference future photo which is not yet taken of the 5 gallon jugs on a boom we will soon add to the test Kayak)

So…  all of these rigs have been slow so far

(Unlike this snail we found at low tide which when fully extended was the size of a cantelope)

But….  just like a goat in a diaper with a cast on its leg at a laundromat…

Good things start small, Fast things start slow, and boats with enough power never sink!

Until next time…  on Adventure


Learn to use Python in a day…

Admittedly I am late to the game with Python.  That said, I have trained and qualified myself in the understanding and use of it.

(NOTE:  I watch these videos at 2X speed…  you may want to start at 1.5X if you are not completely comfortable with programming paradigms)

I started by following this 17 video sequence to understand the new syntax and rules.  Its all basic…  but if you are coming from a different language it can be very confusing at first.  I suggest taking the time to step through the basic videos…  not because you don’t know how to set up an if/else structure…  but simply to get comfortable with the style of Python.

Having a lot of experience using languages that are tightly type cast, agnostic to spacing, and deterministic…  my first response to Python was “Trouble – ACK!”

Type casting was traditionally very important for ensuring compiled results came out as expected…  older compilers would let get into trouble in any number of ways.  Compilers these days are orders of magnitude better…  so…  the harsh rules of the past are no longer relevant.

I accept this as a superior tool for quick collaborative development.

Many good changes to legacy methods have been developed and refined (even though a few stinkers snuck through…  like the confusing for new folks += ) and I have decided that I like the language and want to work with it.

Now…  for some more advanced use cases.


Python… how to decompile it

So you want to see the goodies inside of a PYO or PYC compiled Python file (PY) ???  

If so…  you may.  Its byte code (and not true compiled code…) so it is trivial to decompile into something readable that will get you the information you need or want.

Disclaimer:   Too the nOoB

Now I have been doing this since we were writing code in Assembly…  HEX, Assembly, C, C++, Java…  all languages are essentially the same.  I am old and crusty so I get to do things like this ethically.  We learned in the late 90’s by passing arguments back and forth across the stack between ASM and Turbo C (which we installed with floppy disks…).  The forum named “Stack Overflow”…  well…  I am one of those old guys who had to actually count the bytes in the stack and insert carefully.  I know all about overflowing stacks and writing random information to places it should not be.


1 – Install both Python 2 and Python 3

You will need both to be compliant with legacy and current designs.


2 – Install an IDE of your choice.



3 – Set your PATH variable so that you can execute a command prompt from any window:

RHC start menu, Control panel.  Search “path” and select “edit system environment variables”.  Create a new variable PATH and aim it at your python install.  Separate by semi colon.  Use this tutorial:

Now you are all set…
To run Python from any folder…  click FILE and select CMD.  You will have avoided typing in a long path and much time has been saved.

To run python just type it.

To run a specific version type

py -2

py -3

To run 2 or 3 respectively.


4 – Now…  none of that was required…  but I wanted you to install python so…  now you have.  😉


Meat and potatoes:

I tried 2 of the command line tools.  They were obnoxious…  but there is a GUI that rides on top of them and handles the details for you (if you are a python nOoB like me).

The tool to use is this one:   Easy Python Decompiler

Test Results:

For Python 2 it works.

For Python 3 it APPEARS to crash…  BUT ACTUALLY WORKS…  its simple point and click…  then the file you want magically appears in the source folder.


There you go.  Dont get in trouble and only call the cops if you have to…  Authority figures should be reserved for emergency situations.  Anything else…  I am sure we can handle.