Announcement

Collapse
No announcement yet.

Electronic-trav-a-dial

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Electronic-trav-a-dial

    OK new thread to move away from Black forests thread.

    We finished up asking why it was not possible to use a cheap encoder and one of these also cheap Chinese remote displays.



    Simple cheap encoder with a hardened knurled radiused wheel that can be tilted to get the correct circumference driving into one of these units.

    The protocol for the Chines signals is documented on the Shumatech site which is down at the moment but I may be able to get it elsewhere.

    Basically it's a reversal of what Scott Schumacher has done.

    Any idea's or is anyone up to the job ?
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.




  • #2
    Shumatech at one point made Quadrature to chinese scale converters you plugged inline. So one could just take a rubber wheel connected to a quadrature encoder, and drive one of those displays with off the shelf components.

    Comment


    • #3
      Yes they did, might even have one somewhere.
      However what's needed is quadrature to cheap Chinese display.
      .

      Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



      Comment


      • #4
        I like the idea of this thread. Hope it keep going to a good conclusion. My lathe needs just such a cheap mod.
        VitŮŽria, Brazil

        Comment


        • #5
          Originally posted by John Stevenson
          Yes they did, might even have one somewhere.
          However what's needed is quadrature to cheap Chinese display.
          This is a trivial task for a mcu like an Atmel AVR or PIC.

          Comment


          • #6
            It's a bit simpler.

            Take a microcontroller and feed it with the encoder pulses.

            With an update frequency of say 10 times a second, calculate the encoder position to the real position and write it to a simple LCD display.

            No special components or conversion required.

            The only disadvantage for most people is that it is electronics and software.

            Comment


            • #7
              John,

              The encoder wheel would need a reasonable resolution; e.g. If you used a 5/8" knurl wheel the circumference is approximately 1.96" so a ~1thou" resolution requires at least 2000 pulses per turn.

              The next problem is counting speed; Given the speed at which the carriage can be moved it might prove problematic to use a simple PIC interrupt routine, so it may be better to use a device like the Microchip dsPics that have hardware quadrature counters built in.

              Of course, once you have that kind of processing power handy, there's no real need to have a mechanical trim when it could be done mathematically. And, there's little point using a cheap display device, one may as well include an LCD driven directly by the PIC.

              One un-pursued idea I had, was to use a high resolution optical mouse as a sensor. The better mice claim 1600 dot per inch (which is independent of the surface), so quite a useful device could made with just a simple PC application.

              Bill

              Comment


              • #8
                I need to have another go at reading Chinese caliper protocol with an Arduino. I tried it a couple years ago but didn't really know what I was doing. Should be more than enough oomph to run one or two scales and an LCD.

                Comment


                • #9
                  Originally posted by sansbury
                  I need to have another go at reading Chinese caliper protocol with an Arduino. I tried it a couple years ago but didn't really know what I was doing. Should be more than enough oomph to run one or two scales and an LCD.
                  An Arduino is nothing more than an Atmel AVR running an OS. If you want true power of an AVR, use it natively and program it in Gnu C.

                  Comment


                  • #10
                    Not that the idea may be good.But have you ever tried to stop a moving carriage are mill table on the thousands. With a sweeping dial you can. But with numbers counting up are down. you cant The human mime is not fact enough.With a mechanical Trav A Dial it is easy to watch the dial and throw the feed out at the exact spot. Just some thoughts.
                    Every Mans Work Is A Portrait of Him Self
                    http://sites.google.com/site/machinistsite/TWO-BUDDIES
                    http://s178.photobucket.com/user/lan...?sort=3&page=1

                    Comment


                    • #11
                      Instead of a digital readout what about using a servo motor to move a needle?
                      Gene

                      Comment


                      • #12
                        Originally posted by lane
                        Not that the idea may be good.But have you ever tried to stop a moving carriage are mill table on the thousands. With a sweeping dial you can. But with numbers counting up are down. you cant The human mime is not fact enough.With a mechanical Trav A Dial it is easy to watch the dial and throw the feed out at the exact spot. Just some thoughts.
                        What????? Using gears for a mechanical display??? No backlit LCD's, No crystals, No MCU's runnning at 20mhz, no use of A2D, and Interrupts? Nothing to program?? Wheres the fun in that? OOOhh I know, we could use LED's As you approach thousandth, it goes from yellow, yellow, yellow, green. Or we could make the led blink, and the blink rate increases as you get closer to the thousandth!

                        Yes... One could use PWM to drive an R/C servo to move a needle...
                        I love over engineering.

                        Comment


                        • #13
                          Originally posted by RB211
                          An Arduino is nothing more than an Atmel AVR running an OS. If you want true power of an AVR, use it natively and program it in Gnu C.
                          Are you using a mouse and graphical web browser to post here? Do you have a matching skirt and heels to go with that? REAL MEN USE LYNX AND THE COMMAND LINE!!!

                          For everything I've ever done with an Arduino, the only thing native AVR code has to offer me is more ways to make mistakes.

                          Comment


                          • #14
                            Originally posted by sansbury
                            Are you using a mouse and graphical web browser to post here? Do you have a matching skirt and heels to go with that? REAL MEN USE LYNX AND THE COMMAND LINE!!!

                            For everything I've ever done with an Arduino, the only thing native AVR code has to offer me is more ways to make mistakes.
                            Well, your calling me the one that wears high heals? Your the one defending the use of a "wire" language vs gnu C.
                            But again, some one is going to come on here, call us both panzies for not using Assembly...
                            Ahh the ranks of nerdom..

                            Comment


                            • #15
                              OK forget it - but I thought it was a good idea and would fill a gap.

                              Sigh................
                              .

                              Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



                              Comment

                              Working...
                              X