The greatest electrical tool of all time, the LCR Tester!

Electrical repairs tester

Electrical component tester

This little guy is the greatest thing to happen to electrical projects since the invention of the hammer.  If you are like me, you have a million components on your bench or bins for electronic repairs, upgrades, and circuit design.  I stumbled across this tester on a forum and quickly ordered myself one from ebay.  You can find it by searching for LCR tester.  Why is it the best tool to add to your collection?  Well let me tell you….

measure resistors     Capacitor tester

First, it measures values of resistors and Capacitors (including ESR) with the push of a button.

 

Capacitor tester

It also does diodes…

Electrical component tester     Electrical repairs tester

But BEST OF ALL!  It tells you if  transistors, MOSfets, and the like are good.  But also tells you the values you need to work with these components in your projects.   This is why it’s the best thing since the hammer.  I have tons of components I’ve pulled from boards to use in projects, but finding data sheets etc is a pain.  This makes life easy, especially for breadboard proof of concept and educational circuit design experiments.

The LCR tester comes as a loose board, and is very cheap. I think mine was $15 shipped.  It runs on a 9V battery, and I printed a case on my 3D printer. I’ll find the model and share it here later.  This little device belongs on everyone’s electrical project bench (or toolbox).

 

PROJECT SNEAK PEAK:

LCR TEster pics-2780 LCR TEster pics-2782 LCR TEster pics-2783

 

Partially so I can find the driver board specs in the future, but I’ve been playing with Lasers for the last 6-9 months working on some different types of rapid prototyping machines.  More to follow but the sneak peak photos show some of my test parts as a tease.

 

Ducted fan designs, an early project sneak peek

3d printed ducted rotor aircraft engine

3d printed ducted rotor aircraft engine

This post is an early sneak peek at a project I have been working on in my spare time.  I showed a friend who stopped by and he told someone else an I was pestered to share pics and a video.  I have been experimenting with ducted fan thrust generation with a planned application.  As for what  that application is…  Well it is not ready for the world yet and I will let you use your imagination.

thrust generating ducted rotor     3d printed ducted fan thrust generator

Mostly eye candy at this stage of the game, I have tested 3 different rotor designs without getting into complex blade geometries to date. I have primarily been focused on printing rotors that have little wall clearance and hand finishing them to minimize the gap between the duct and rotor blade.  Research papers I have read shows that this area is critical to ducted fan efficiency and design.

ducted fan design 3d printed-9400

I am currently using a set up with a friction fit on a taper to lock the two halves together so I can get at the motor.  This little bad boy screams when she spools up.  In the shop it sounds like a mini jet engine starting up.   I am working on test platform speed a controller for it using an Arduino nano and components..

rotor design for ducted fan

You can see that this needs lots of cleaning and smoothing before final thrust measurements.  I plan to put it through an acetone bath treatment and then do a bit of hand finishing to smooth out the inner walls to reduce any drag from the 3d printed irregularities.  Eventually I’ll make a rotor balancing jig to fine tune the balance on the rotor.  Future iterations will likely have continually reduced rotor mass to decrease inertia.  I am testing behind a 1/4″ polycarbonate shield in case of catastrophic failure.

ducted fan design 3d printed-9401Here’s one with my hand to provide you with a sense of scale.  I will try to get a video of it spinning at moderate speed.  Without a speed controller I’m reluctant to limit test the high speed operation at this stage of development.  I will put a video up here later this weekend if I can find time. 

How to Make a Minion Costume for Halloween– Part 2 ( 3D Printed Minion Goggles )

3D printed Minion Goggles

How to Make A Minion Costume Halloween-8500

This post is a continuation of my previous post and will primarily cover the design and printing of the Minion Goggles with eyeballs used  for my Minion Halloween Costume.  I spent the bulk of my costume time designing acurate 3D models in CAD software of the Minions eyes and goggles.  I wanted to make this the focal point of my costume and went to great lengths studying photos measuring toys, and watching the movies and shorts to get scale, proportion and details correct on this part of my Minion Costume for Halloween.  My goggles are designed to fit onto a 12″ diameter foam Minion head( ~11.5″x 5″x5″ dimensions.  My 3D printer is much larger then most of the hobby FDM style printers out there,  allowing me to build parts of  this size in one piece.  If you want to build one you can print it in smaller pieces and glue it up. I broke my model into 2 pieces so it would print easily and without wasted filament on support structures.

3D printed Minion Goggles

Above, you can see the software printing out one of the 3 pieces of my Minion goggle design. The current layer is highlighted in red on the screen.  I use Pronterface (seen above) and Slic3r to turn CAD models into plastic parts with my printer.  Both are amazing pieces of open source software built by the 3D printing community.  I printed it in 3 pieces to keep the weight down and use less filament.  The goggles when completed weighed in at ~1 lb. Quite heavy considering they are 6″  out from the center line of your head.  I designed the Minion Goggles to be printed as multiple pieces to simplify painting, allowing for true to character final product.  My Despicable Me Minion Goggle Design have 2 clear plexiglass lenses for that true “goggle” look.  This keeps dirt/food/stuff of the painted eyeball area and makes the eyeballs appear more glossy and lifelike.

3D printed Minion Goggles

3D printed Minion Goggles

 

3D printed Minion Goggles

The blue stuff in the above photos is Silicon RTV adhesive.  At about 4 hours into the almost 9 hour build there was some warping and pulling away of the parts from the Kapton tape covered heated bed build platform. I slathered on some RTV to prevent further warping and prevent the build from being ruined due to the part separating from the build tray.

3D printed Minion Goggles
I did not take a enough photos, this is the front Goggle lens retainer being built. I used support so the “rivets” around the outer perimeter would build cleanly.  I was careful to count, scale, and locate the rivets based on many photos and screen shots from the DVD.

3D printed Minion Goggles

This is the rear piece that will fit up against the foam minion head that I was constructing for my costume.  The head diameter on my costume is 12″ as this was the largest foam circular shape (more on this in Part 3 of Minion Costum Construction) I could find for a reasonable price.

Despicable Me Minion Costume Goggles Halloween - 2    Despicable Me Minion Costume Goggles Halloween Costume - Assembly    Despicable Me Minion Costume Goggles Halloween

I have uploaded the 3D cad models for my Minion Goggle design onto Thingiverse ( http://www.thingiverse.com/thing:232679 ) in both STL and an IGS assembly in case you want to make a Minion Halloween Costume of your own with some modifications.  Just remember that the goggles are designed to fit on a 12″ diameter head.  You can scale them if you are making a smaller costume for a kid.  If you use my files and make a costume, please send me a pic, I would love to see what you came up with and how it came out.

3D printed Minion Goggles      h

The raw printed goggles held up against the foam so you can see how they will fit on the Minion Head/helmet.

3D printed Minion Goggles   3D printed Minion Goggles

The painted goggles came out well.  In the above left you can see the acrylic disc that fits in the groove on the notepad. The outer frame is a snug enough interference fit that it retains them without any glue.   In my original design I was going to use foam for the helmet, however the foam ring was not up to the task of supporting the 1 lb printed goggles.  I cut a piece of 2 yellow pine into a ring for this purpose.   One more thing to note, should you follow in my footsteps on this DIY Minion Halloween Costume,  the weight of the goggles is too much without a counterbalance at the rear.  I attached with screws a steel plate(approximately 4 in x 6 in x 0.125 in) that I hammer formed to the 12″ diameter  counter the weight of the goggles.  This brings the helmet/head up to about 2.5 lbs.

minion goggles final

More on my Minion Costume Construction in the next and final post on Making a Minion Costume for Halloween – Part 3 where I will show you how I made the helmet, and talk about designing/making the fabric portions of my Minion Costume. 

Enclosing your 3D Printer

3D printer enclosure finished-8272

With my 3D printer dialed in and tuned up, I was still having issues with the temperature on the heated bed and parts warping.  I determined that this was due to external air currents in the room.  I had been considering building a permanent table for the 3D printer and added an enclosure to my design to eliminate the effects of drafts on printed parts.  The enclosure is nothing fancy, very low tech in fact.  It is a corner framed box made from 1/4″ luan plywood with sliding plexiglass front doors.  It has handles and easily lifts off for maintenance and upgrades.

3D printer enclosure-8266    Enclosing a 3D printer -8270

The table is made from 5/4 pine lumber I had cut a few years back when the electric company cleared power lines along the property.  It has a full width drawer that slides out fully. I needed a place to hold  the tools and parts used to maintain the 3D printer in tip top shape. The small shelf in the back keeps the power supply and other wiring off the floor for better airflow and cooling of these units.

3D printer workstation -8267

For now, my 3D printer is driven by a computer and it has a nice new workstation courtesy of my good friends Mark and Michelle who donated the computer desk to the cause.  I also use this computer for development and programming of other projects like; Tetro the quadroped robot and Filastruder the filament extruder that will feed the 3d printer filament made from recycled plastic, and other cool things I’m not ready to leak to the public at this time. 🙂  Have no fear there will be blog posts on tetro and filastruder as I find the time.

3D printer LED lighted print head - 8275     3D printer LED lighted print head  -8274

Adding the enclosure required some necessary additions to the printer.  First was lights on the print head. I used to not understand why people would put lights on their print head, but now I get it.  When it’s running it’s important to monitor filament laydown and in the enclosure it’s pretty hard to do so without the lights.  I added three high brightness LEDs aimed at the print area to the left side of the x axis sled.

3d printer enclosure upgrade-8417

I used 12V SMT LED light strip which is readily available from online suppliers to light the entire enclosure.  The above photo shows the strip attached with a pressure sensative adhesive strip to the inside front of the printer enclosure.  The 30″ of light strip provides more then enough light for the enclosure.

3d printer enclosure upgrade-8419    3d printer enclosure upgrade-8418

Above photos show the effectiveness of the LED light tape.  Left photo lights off, right photo lights on.  A worthy addition to the printer.

3d printer enclosure upgrade-8421

What’s left to do to the printer before it is done?  My next steps will involve some changes to the control interface and enclosing the electronics that drive the printer (seen in the above photo).  These changes will turn my 3D printer will be a true stand alone machine with an LCD display, control interface via buttons and dials, and an SD card reader.    This will eliminate the need to have the PC running or even connected to the printer for operation.