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  • Author Author: jasonwier92
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PDU #9 - Why Do I Do It? [Upcycle It Challenge]

jasonwier92

Ever get so far in a task/project and wonder if it is worth doing or if you could do it over if you would do it different? I know, all the time. This weeks update is no different. I was making my relay control board that I mentioned in the last BLOG entry and I have had a hundred "why am I doing this" moments when making this circuit.

 

Here is the circuit I am building, but eight of these, so they will fit on one board right? Oh my, yes, but in hind sight I might have done it different.  Maybe even etched a board and I have not etched a board in 25 years, since high school.

 

image

 

I have added a 7805 and a few capacitors to get 5V.  I will bring in 12V from the Edison interface board and then return 5V to the Edison board for use with the LCD. Only other thing I am missing on the board is pins to run to the LED board.  I have tested for continuity and made sure all that needs to be isolated does not have continuity. Also there is a dual line header at the end opposite of the relay header and that will be for a ribbon cable to the Intel Edison board.

 

Here is what it looks like:

 

 

{gallery} The Board

Top view. I cannot imagine putting anything more on this board, this was almost too much already.

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Bottom

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Mated with the relay board

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Another view of it mounted.

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Bottom view

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Side view, sporty and fast.

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  • I have never finished a project in which I wish I could do over and make it better.

     

    Unfortunately, when you do one of a kind projects, this is just not possible.  Though I did get the opportunity to move a working system to an upgraded device.  Even with the upgrade and redesign, our integration worked after we just changed two wires from the initial delivery.  Took 30 minutes and the customer was very impressed.

     

    So do not despair.  You are experiencing a normal engineering post project depression.  You will get over it.

     

    DAB

  • but in hind sight I might have done it different

    Yep been there, done that.

     

     

    You could have skipped the resistor on the relay control side

    You've already provided a pull-up with the LED and resistor, and an open collector works just fine.

    It wouldn't have saved a lot.

     

    One thought I've had (now that you've built this one image)

    If you used level conversion to drive the input side (or perhaps a minor modification to the onboard LED or resistor), and wired the LED on the relay board side.

     

     

    Next week I might see if I can drive one of these type of Relay Boards directly from the Edison.

    The 1.8v I/O needs some solutions that we can easily apply, and while the level conversion is one solution, it requires extra bits to be added.

     

    I reduced the resistor value for the 3v3 RPi, so removing the LED might be enough.

     

    Mark

  • in reply to jasonwier92

    Oh and looking back, I would have run the ground around the outside and the 5V down the middle, just because I think that design is better.

  • in reply to Workshopshed

    I would not have done the power conversion on this board if I planned it better.  There was already two changes:

     

    • First I was doing the LED resistors here, but decided that was not needed, it can be the LED circuit and it would be less wires.
    • I had all the transistors running 90 degrees to where they are now, but then decided ground side and 5V side