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Test Set/Test Fixture

  • Starting a new project that will utilize the cables I made in the project log entitled "128 Pin Connector". It is going to be a test fixture that will be apart of an entire test-set with the 128 pin cables included in the test-set. The test fixture will allow access to test points for all the pins on the device and will be used in software development as well as DO-160 testing.

    The piece of equipment this is for is a wireless access point for jets that will allow wireless connectivity for passenger's PDA's, smart phones, laptops, and other similar network and internet ready devices. This thing doesn't communicate with the internet itself but will interface with other equipment that provides links to satellites.

    In a nutshell, it's a wireless router in the sky that provides wireless access to the internet (and the LAN) for anyone on board.
    Note: Don't expect to see an item like this on your next flight with a commercial airline anytime real soon. Our customer base is mainly private corporate jets or fleets of such aircraft. Once the Iridium Network goes though some planned growth and upgrades (between 2013 to 2015) and adopts a more affordable price plans for Iridium Network Providers the cost is only practical for such high dollar clientele applications. After the changes the band width will be expanded thus allowing for more volume and thus a lower price point.

    To kick things off I need to brainstorm, create drawings (simple block style), research part numbers and cost, come up with a Theory of Operation, create a keynote or power point presentation, and then present it.

    I have already started that process and it is due on the 21st. I don't think I'll post much in here until after that date as my drawing are often changing while I'm putting everything together for the presentation.

    I know this much for sure:
    The 128 pin (not all pins used) will have a D-sub 50 and a D-sub 37 (DD-50 & DC-37) on the ends
    • These will be male and female alternating to prevent the two cables to be incorrectly connected to the test fixture. We accomplish a "dummy" proof system without having to spend hundreds on FAA approved connectors and will not require any keying.
    • There will be the oppisite pin type (male/female) on the test fixture for mating
    • The outputs will be displayed using LEDs
      • I think there are 12 of them
    • The inputs will be simple toggle switches
      • I think there are 12 of them
    • There will be RJ45 keystones
      • I think there are 7 of them
    • There will be RJ11 keystones
      • I think there are 11 of them
    • D-sub 9's (DE-9; aka DB-9s) will be available for the serial bus
      • There are 4 of these
    • D-Sub 9's (DE-9; aka DB-9s) will be used for the ARINC429 Bus
      • There are 2 of these
    • There may or may not be a USB hub installed in the test fixture
      • The router can support up to 6 USB ports but physically only has one. The port is used for maintenance on ground; not accessible in flight in most configurations. I'll have to wait until my meeting on the 21st before knowing for sure if the USB will go through the text fixture or just be on it own stand alone cable and/or dongle device.
    • Lastly, the power cable (not one of the two 128 pin cables) will be connected straight to a power source and WILL NOT be routed through the test fixture.
      • There is a pin on one of the 128 pin cables that will provide a status of power on the router and will be indicated on the test fixture via an LED (different than the output LEDs mentioned above.

    I don't work from the 21st to the 1st but I will most likely work on this at home during the break and will make sure to get some eye candy content up here. I am really excited about this build. I hope all who follow it enjoy it as well.

    I am building a test fixture and associated cables (click here for project log of the cables) . I have the requirements for the test fixture and have already gone through the initial design process on this.

    Requirements:
    • 12 Inputs - Going to use SPDT switches here.
    • 12 Outputs - Going to use LEDs for this.
    • 2 WiFi & 4G on/off switches (1 ea)
    • 11 RJ-45 Jacks
    • 8 RJ-11 Jacks
    • 6 Serial Ports
    • 1 Power Dectect On/Off LED
    • 1 Set of banana jacks (red & black)

    I had, at first, all this on one PCB (Printed Circuit Board) with the connecting cables coming in through the rear of a project box (still undecided on my box) via 4 D-SUB (D-Sub or Subminiature WiKi) connectors.

    Now I know I only have two cables but I didn't want to have to spend huge amounts of money on the connectors that mount up to the actual device I'll be testing. However, I still wanted to keep the "dummy proof" keying features that came on the expensive connectors. I need about 85 connects on one cable and less then that on the other so I ended up splitting each cable into two d-sub connectors, each having one DD-50 (aka DB-50) and one DC-37 (aka DB-37). I made one 50 pin male and the other female and did the same thing with the 37s. Doing it this way I have eliminated the possibility of a catastrophic user error when connecting the cables. There is still the possibility to connect a female to a female but not to worry; however interesting this is it is hardly catastrophic to my equipment. :eek: That sounded oddly inappropriate LoL!

    The 6 serial port I am using DE-9s (aka DB-9), all female. I am mounting these on the rear of the box as well. The DE-9s are going to be three sets of stacked TH style and will be mounted to the bottom back edge of my PCB along with the D-subs above.... Forgot to mention the DC-37s are also stacked.

    The RJ ports (RJ or Registered Jack Wiki) will be on the top along with all the switches and LEDs and banana jacks. Everything but the switches were going to mounted to the PCB on the top with a header going from a ribbon cable to the 12 switches. After a design review we have decided to mount the switches to a PCB and use the header and ribbon cable to connect the two PCBs

    The banana jacks were also going to be TH style. Now I forgot to mention that everything on the top of the PCB will not have panel mounts, stops, or any other panel features. They will all be just a through and through. We didn't want the banana jacks to rely on only the solder joint as a mechanical mount so I added a three pin header to the main PCB and I will use a small ribbon cable to wire to panel mount banana jacks.

    Once these board get assembled I will add some pictures but right now everything is only in the design on paper phase.... paper, computer, ect...

    After finding the right box for my project and making sure all stocked parts are available from my BOM I am ready to have my bear board printed up. Already have a quote and I'll be building 5 of these things. One my bare board come in and all the parts I will begin the build with pics and everything. Should be fun.
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