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    • #8223
      LectronFan
      Moderator

      Hi all,

      How about adding a new module to the Digital Logic Lab which is able to display the numbers 0 to 9 in Decimal and 10 to 15 in Hex ?

      Well, here it is !

      This module is a nice add on for the Lectron counter 4520. It simply snaps at the right of it and will display the numbers presented at it’s Q0 -Q3 inputs. The same Q0-Q3 is available at the right of the new display module so it can be placed in existing circuits without the need of  rewiring it.

      So, what is HEX ?

      Well, following table explains it all :

      HEX Table

      Normal  display drivers such as the CD4511 only display the numbers 0 to 9. The HEX numbers A,B,C,D,E and F are simply ignored.

      To display these, we will need a special driver chip which is not available anymore (obsolete).

      I decided to use a microcontroller with some discrete components. It scans the inputs and outputs a HEX number to the 7 segment led display. This happens at a clock rate of 8 Mhz, fast enough for our Lectron circuits. The module is very power friendly thanks to the use of a segment display operating at a very low current (typical 1mA per segment). It emits a bright readout though.

      It is safely powered by 9V thanks to a small voltage regulator build in the display module.

      Here are some pictures :

      HEX display1

      HEX display2

      HEX display setup

      And here a video of the working principle : Lectron HEX display

      Many greetings,

      Frank

       

       

       

      • This topic was modified 1 month, 3 weeks ago by LectronFan.
      • This topic was modified 1 month, 3 weeks ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8226
      mwpeters75
      Keymaster

      Hi Frank,

      Wow, this is really excellent customization work.  A hex display has never been done before (to my knowledge), congratulations!  I especially appreciate the video showing the new circuit in action.  Wonderful!  

      Your vacation has really put you into high gear 🙂 

      Welcome back and thank you for this new circuit!

      Best,
      Michael

      • This reply was modified 1 month, 3 weeks ago by mwpeters75.
    • #8238
      Guenni75
      Moderator

      Hi Frank,

      that is really helpful and great work, thank you!

      Which obsolete hex driver do you mean? Perhaps I may find a collector of these specials with that IC…

      May I offer your block in my (our!) Lectron File Card Collection?

      Best,

      G.

      • This reply was modified 1 month, 3 weeks ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8240
      LectronFan
      Moderator

      Hello Guenther,

      Very kind of you to check for this chip.

      The driver chip mentioned is a MC14495 and can still be found but it’s quite expensive.

      And for fellow Lectroneers who want to build this module, it would be easier to use a ATTINY84.

      It has the advantage that it costs only €2 and that the program can easily be adapted.

      Also the chip is widely available.

      I will gladly share the code if anyone’s interested and I still have a few PCB’s.

      I would be honored if you would add this module to your library, many thanks.

      Maybe Lectron is also interested ?

      Many greetings

      • This reply was modified 1 month, 3 weeks ago by mwpeters75. Reason: Changed font and size styling for easier reading
      • #8247
        mwpeters75
        Keymaster

        Hi Frank,

        Sadly, there will likely be no further Lectron System development as Mr. Kopperschmidt has ceased being involved with Lectron, GmbH.  There are no plans that I am aware of regarding replacing Mr. Kopperschmidt’s role as developer and designer.  I hope that I am wrong about this!

        • This reply was modified 1 month, 3 weeks ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8253
      Guenni75
      Moderator

      I ordered the MC14495 for EUR 1.36 including shippment – let’s see if / when it will arrive…

      G.

      • This reply was modified 1 month, 2 weeks ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8258
      LectronFan
      Moderator

      Hi Guenther,

      This is really a great find !

      I will make a PCB for this chip and try it out.

      More info soon …

      • This reply was modified 1 month, 2 weeks ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8313
      Guenni75
      Moderator

      Here is my test board with the CD4520 and MC14495 – and some photos. Works very good and is easily done!

      By the way, Frank: you got a new tab in my physical Lectron card file and all your circuits are still printed and are awaiting my tests and response – please be patient for feedbacks because I have a lot work to do before – sorry…

      Best,

      G.

      • This reply was modified 1 month ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8315
      LectronFan
      Moderator

      Hello Guenther,

      What a cool setup you have, very old Skool !I’m still figuring out how to place this chip on the rather small PCB. I need some time to accomplish this.

      It would be nice to have the MC14495 chip for the display driver.

      Thank you for honour me in your classification system. I hope you will find some time to try the experiments out. Feedback is so helpful and stimulating.

      Greetings

      • This reply was modified 1 month ago by mwpeters75.
    • #8317
      Guenni75
      Moderator

      Hello Frank,

      do you still looking for a MC14495? May be I had no thoughts as I ordered only one piece… Should I order “a hand full” of these IC for us? Please let me know – the shipping of this was much shorter than estimated.

      On the other hand – I have to order more empty Lectron blocks and contacts before starting more / new “projects”…

      Best regards,

      Günther

      • This reply was modified 1 month ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8318
      LectronFan
      Moderator

      Hello Guenther,

      Well, let me try to build a pcb for this chip.

      The advantage of the microchip that I used was the fact that it’s inputs and outputs can be freely assigned to the pins.

      It is also smaller (14 pins instead of 16) and just fits on the module pcb.

      The MC14495 needs to be rotated 90°.

      I will try things out  this evening.

      Greetings

      • This reply was modified 1 month ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8319
      Guenni75
      Moderator

      In my block (with a veroboard-like PCB) also a DIL-18 socket will fit, see photo:

      …so it’s not a problem for me. The 7 segment unit is a very old CQY91K from the 1970ies – I believe…

      Best,

      G.

      • This reply was modified 1 month ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8320
      LectronFan
      Moderator

      Hello Guenther,

      You found a neat solution by using veroboard. The advantage is that you wire it the way you want and can cut it to size.

      I would prefer a finished PCB and this has to fit in the narrow space (making cutouts in the PCB will be more expensive).

      I didn’t find the time this evening to work on the pcb layout, maybe tomorrow.

      Your led segment would nicely fit in the Legacy digital blocks !

      I’m interested in that led display, if you like I can also design a PCB to fit in a 2×2 cube (just like the Legacy flip flop. What do you think ? In return I will send you the finished pcb.

      In the design I made, I used a low current led display so the battery will live longer 😛

      Many greetings

      • This reply was modified 1 month ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8329
      Guenni75
      Moderator

      Hi Frank,

      your offer sounds damned good – thanks in advance!

      Best,

      G.

      • This reply was modified 1 month ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #8512
      Guenni75
      Moderator

      Hi all,

      here is my latest version – sorry for the delay – but:

      however, I first had to “cannibalize” suitable legacy blocks to be able to create the three required blocks (since Lectron GmbH could not / did not want to supply me …) with regular wiring techniques:

      The ICs CD4011, CD4520 und MC14495 were used and the function is well using a battery with 5V (4 x 1.22 V) – not with the 9V printed on the connection block.

      Best,

      G.

      • This reply was modified 4 days, 8 hours ago by mwpeters75. Reason: Changed font and size styling for easier reading
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