Need Help! DRO Design discrepancies.

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Thread: DRO Design discrepancies.

  1. #1
    Join Date
    Jan 2014

    Default DRO Design discrepancies.


    I was looking with great interest at Bill Todd's DRO designs, and I really want to build this one - I am quite at home with electronic assembly and PCB manufacture - but although an impressive amount of work has obviously gone into the design, the information downloaded appears to be fragmented and inconsistent, therefore I am having problems verifying schematic to PCB layout.

    Having downloaded the Zip package for Version 1.2.05, I found the PCB layout PDF file, but there was no schematic. I downloaded the schematic separately from the forum, but one does not verify with the other. The PCB layout has numbered components and nets given, the schematic has no numbering - just question marks. I have tried tracing by eye, but there are several discrepancies. eg pin 7 of the DB9 goes nowhere on the schematic, but is connected on the PCB; there are 2 diode cathodes to 3.5V on the PCB, but only 1 on the schematic; there are 2 resistors to DB9 pin 4 on the PCB but only 1 shown on the schematic. I gave up at this point as clearly the schematic that I have is not the one that the PCB was netlisted and routed from.

    Is there a schematic and PCB layout that are a matching set somewhere, or alternatively a definitive schematic somewhere that I can confidently use to netlist and route my own PCB from?

    I really don't want to spoil a good project or waste time and money by going off half cock, so I trust some kind soul will be able to point me in the right direction.


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  2. #2
    Join Date
    Aug 2008

    Default Re: DRO Design discrepancies.


    Attached are the only schematic and pcb layout that I have of the DRO. You should bare in mind that I designed this some years ago for use with the 1.5V (positive frame) callipers that were around at the time. Modern callipers and scales have moved to a 3v (positive or floating frame) that require a different ground and power arrangement.

    I've pretty much given up developing the PC application as there is a better Andriod tablet based app being developed by Yuriy
    (Yuriy's Toys: Android DRO Project)

    I will at some stage update the PIC code to work with Yuriy's DRO but I have little time these days (personal reasons) so it could be a while before i get a 'round tuit'


    Bill Todd

    Attached Thumbnails Attached Thumbnails DRO Design discrepancies.-dro-pdf   DRO Design discrepancies.-multichannel-reader-pdf  

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DRO Design discrepancies.

DRO Design discrepancies.

DRO Design discrepancies.