• Using Side View LEDs in place of Reverse Mount LEDs

    04/11/2019 at 03:15 5 comments

    So if you've seen damn near anything I've done for the last 18 months then you've seen examples of using Reverse Mount LEDs and also manually mounting LEDs upside down. 

    A sample of my projects from 2018, all using reverse mounted LEDs
    Reverse Gullwing LED & 1206 LED Properly Abused

    I like shining LEDs through PCBs, it's a great lighting effect and it isn't as harsh a light as you get from having the LEDs on the top side of the board.  However there are a handful of draw backs to using them.

    Reverse Gullwing LEDs:

    • They're expensive.
      1. "Reverse Gullwing" LEDs are just expensive.  Even quantities of 1,000s RGB Reverse Gullwing LEDs are over $0.40/ea as compared to $0.02-0.04 you typically see with a comparable size LED.
    • They're exceedingly rare.
      1. This point is pretty obvious based on the price but there are only about 3 manufactures that make LEDs in this package and only 1 of them makes the RGB variant.
    • Minimal light propagation
      1. If you're putting an LED directly onto the PCB that it's shining through then you only get a circle that is about 9mm in diameter.  This varies based on the color, voltage, resistor used etc but in general it's only 9mm and it takes a crap load of LEDs to cover a relatively small area.  This only exacerbates the first issue.

    Reverse Mounting Normal LEDs:

    • Not Pick n' Place Friendly
      1. Soldering LEDs Upside Down on purpose involves a lot of manual labor and is not solder paste or Pick n' Place friendly, this means it's a solution that does not scale well at all.
    • Same Light Propagation Problem as Reverse Gullwing LEDs

    So between these two solutions there is the classic "Cheap, Fast, Good, pick two" dilemma.  Reverse Gullwings are Expensive, but fast and good.  Manually soldering LEDs upside down is Cheap, Slow, but also Good.  Now let's look at another solution: Side View LEDs.

    Side View LEDs

    Side View LEDs are exactly what the name says.  They're LEDs that instead of shining up or down they shine at a right angle.  Side View LEDs are cheap, pick n' place friendly, and you can get them in every standard LED color including UV and RGB.  My initial interest in Side View LEDs came from wanting to use the UV variant on some projects to get that eerie glow you get when UV light is shined onto FR4.

    The glowing eyes are from the UV Light, they are not back lit.

    This is an effect I still intend to use on future projects but I also saw the possibility that I could use Side View LEDs in place of Reverse Mounted LEDs.  Unfortunately it isn't as simple as just replacing one foot print for another.   Side View LEDs were not designed to be used for this purpose, they're designed to, well, shine light at an angle and are typically used as indicator lights in most consumer applications, think something along the lines of status indicator lights on a Laptop.  As such there is a tremendous amount of light bleed that you have to control.

    The other major issue with using Side View LEDs is that the light that does shine below them isn't as bright as using a Reverse Gullwing or a typical LED mounted upside down. Due to their vary nature the light they output isn't in a circle it's more like a 1/2 Circle or a very wide cone so you have to rethink your designs to take advantage of that as well.

    Pink Side View LEDs

    I designed a simple prototyping board so that I could get measurements and figure out how to best work with these LEDs before I put them in a project.  I am very glad I did this because despite having seen other examples of Side View LEDs being fantastic drop in solution for back lighting PCBs I instead found it had its own draw backs.

    • Uneven Lighting
      1. So this is similar...
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  • SAOv1 to SAOv1.69bis Upconvert Tutorial

    03/21/2019 at 01:57 1 comment

    When we were working on the SAOv1.69bis "Standard" a primary goal was to maintain backwards compatibility.  This is great for everyone who collected so many SAOs from DC26.  A major upgrade for v1.69bis is mechanical stability added by using a Keyed Shroud and a matching Keyed Female connector on the badge.  Based on the bulk order I recently placed I believe most of the Independent badges will have Keyed Female Badge connections.   To best take advantage of these changes I've put together this Up conversion tutorial.

    This tutorial will address two scenarios:

    1. SAOv1 without the 2x2 Header Soldered on.

    2. SAOv1 with an existing 2x2 Header Soldered on.

    If you need to buy some 2x3 Headers for this project here is an non-sponsored link to the listing I purchased mine from on Amazon.

    This tutorial does not require any desoldering!

    Scenario 1. - No Headers

    If you some how still have a SAO without any headers soldered on then the solution to your problem is easy: Remove the 2 left most pins.

    Then solder the header on with the "Arrow" on the top pointing towards the "VCC" mark on the SAO.

    That's it, you're done.

    Scenario 2. - Headers Already Soldered On

    This situation involves a little more work but is still very easy and doesn't require any soldering or desoldering at all!

    Here is what you need:

    • A Pair of Needle Nose Pliers
    • 1x 2x3 0.1" Pitch IDC Header (Shrouded Male Header)
    • Your SAO

    Step 1. Remove the Spacer

    The first step is to remove the plastic spacer on the SAO Header.  Using your Needle nose pliers clamp onto the header and just pull straight off.  If you have a Surface Mount SAO Header instead of through hole you might want to use a hair dryer or heat gun to heat up the plastic first so you don't rip off the contacts.

    Grip only the plastic and pull up, do not twist!
    v1 SAO with Plastic Spacer Removed

    Step 2. Remove the pins from the 2x3 Header

    Pretty self explanatory,  Using your needle nose pliers remove all of the pins from the 2x3 IDC Header.   Don't twist or anything just grip the pin tightly and pull away.

    2x3 0.1" IDC Shroud With Pins Removed

    Step 3. Slide the 2x3 Shroud on top of the 2x2 Pins

    Slide the 2x3 Shroud on top of the 2x2 Pins with the "Arrow" on the shroud pointing towards "VCC" on the SAO.  If your SAO isn't labeled it should be the top left pin.

    The Arrow Should Point at the Top Left Pin
    A Completed SAOv1.69 Conversion

    Step 4. Test your SAO & Enjoy

    Finally, plug your SAO into your badge of choice and make sure it functions as it should.  Being that you didn't have to desolder anything it should work just fine.

    Big Green on the Queercon 15 Badge

  • My DEF CON 26 Talk Notes

    08/11/2018 at 19:35 0 comments

    Getting To Blinky 4.0

    https://contextualelectronics.com/courses/getting-to-blinky/

    This is where I recommend everyone start for learning KiCAD.  It's an entirely step-by-step tutorial that  gives you the foundational knowledge required for using KiCAD.

    Keep in mind this Tutorial was written for KiCAD 4.0 and KiCAD 5.0 is a little different.  I would recommend installing KiCAD 4.0, following Chris's tutorials, do a couple of simple projects for fun, then upgrade to KiCAD 5.0.   Chris is working on an updated 5.0 series but if you want to start now that is what I would recommend.

    svg2shenzhen Inkscape Extension

    This is the plugin that I talked extensively about and use a great deal for my projects.

    https://github.com/badgeek/svg2shenzhen

    How I make Shitty Add-ons

    This is the stream I did in June on how to make SAOs.  

    PCB Color Reference Spreadsheet

    This applies only to PCBWay, and is only meant to give you a rough idea of what to expect.

    https://docs.google.com/spreadsheets/d/1dmkTsKZDV5iltQbpEa_QOL5XYEONms_M1ZETBNO5ub4/edit?usp=sharing