Wrestling with Filament on your 3D Printer?

My Solidoodle 3 printer finally came in last week and I was able to pretty much plug it in and start printing. I immediately noticed that something needed to be done about the filament spool. With it being a new spool, the filament was just falling off  at the slightest turn on the PVC holder which was really annoying because that meant I had to babysit it. So with a small filament holder I found on thingiverse and some old folders, I was able to come up with a solution that allows me to hit ‘print’ and then just walk away until my print is done.

Multirotor Acronyms, Terms, and More…

I’m learning about Quadrotors, Tricopters, Hexacopters, and other multirotors and I have noticed that there are a bunch of acronyms, terms, and definitions that I don’t know. This is typical when learning any new hobby.  So this post is simply a list of those acronyms and terms along with a few photos and definitions. I will add more as I come across them. Feel free to leave anything I missed in the comments section and I will add it to the list.  Click on More to view the entire list.


ARTF – Almost Ready to Fly
BEC – Battery Elimination Circuit
BNF – Bind-N- Fly
ESC - Electric Speed Control
GPS – Global Posistioning System
FC – Flight Control Board
FFF – Fast Forward Flight
PNP – Plug and Play
RTF – Ready To Fly
RTH – Return To Home
RX – Receiver
TX – Transmitter

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Back to Basics: Ohms Law

During last night’s Open Hack Night, while trying to explain things like how transistors and mosfets work, it was discussed that maybe taking a step back and outlining some of the basics of electronics would be beneficial to everyone.  So I decided to start with Ohms Law.

There are 3 things that Ohms Law deals with, and they are all related to each other.  Those things are Voltage, Current and Resistance.

Voltage is measured in… well Volts of course!

Current is measured in Amperes.

Resistance is measured in Ohms!  Named after this guy who put a bunch of work in discovering resistive properties electricity, and apparently came up with this relationship known as Ohms Law.  Anyhoo.

I like analogy’s to help me relate things that I know, against things I don’t know.  So everyone’s favorite analogy of electricity is water.  Some will argue this topic to death, but for my purpose I’m sticking to it.

Voltage — So Voltage is actually a potential concept, think of a large water tank on the top of a hill and a small pipe coming out of the bottom.  The difference between what is coming out of the pipe versus the pressure in the tank is the potential voltage.  So voltage is the pressure.

Current — This would be the volume of water pushed through that pipe by the voltage (pressure) and would refer to the quantity of water flowing through it.

Resistance — So this would be the pipe its self.  The larger the pipe (lower resistance), the easier current can flow through, thus having more current.  The smaller the pipe (higher resistance), the harder it is for the current to flow through the pipe, yielding less water.

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The little gerber viewer that could!

Of course I’m talking about gerbv!  For those of you who don’t know, gerbv is a free Gerber or RS-274X viewer that comes from the gEDA Project.  It’s free, it’s open source, it’s cross platform… (quick link to windows version download here) and that’s awesome.

So, why do you care?  Well, if you are building your own circuits and want to get a PCB made then usually the format you’ll need to export your design into is a gerber.  The reason you should grab gerbv is to double check for errors.  When you design a PCB in your favorite circuit layout tool, whether it be Eagle, Altium, or my favorite DipTrace, you should double check for errors.

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Power over ethernet, sorta

So we’re still busy decking out the new facility and one of the things we wanted to get up and running is some cheap surplus ethernet cameras to … keep an eye on things and check out whats going on remotely.   So I thought I’d go ahead and set these guys up.

First thing up was to make some cat5 cables.  I got a cheapo crimper, cable tester, and connectors off eBay.  While trying to figure out how much cable I need to run  I was thinking about how I’m going to plug the cameras in to supply power.  They have wall warts with barrel jacks running 12 volts.  I started thinking about how power over ethernet works and thought I’d try to see how I can do the same thing to run the power to the camera.  These aren’t POE cameras so the idea was to only half crimp the connectors, and use the unused pairs to run the 12 volts.

Here is the layout of how cat 5 cables should be done.  Credits to wikipedia.

So there are 2 color coded standards for crimping cables, but oddly enough, the ones we care about are blue, blue/white, white/brown, and brown.  Pins 4, 5, 7, 8.  These pins aren’t used in 10/100 connections, however if it was gigabit then they would be used.  So the unused pins are the same on both standards, so I just chose the first one.

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