For the display I wanted something more interesting than a simple binary readout. I decided to go with the retro look and use some IV-9 russian Numitron tubes that can be conveniently driven by 5V with 20mA of current, the perfect amount to use a 4511 7-segment decoder. The only problem in the way of a steampunk output for my computer was converting the base-16 output of my computer into 3 digits of base-10 binary coded decimals.

Binary coded decimals are exactly what they sound like. The BCD system uses binary values 0-9 to express the base-10 digits that we use every day. For instance, the binary number 132 (10000100) would be 0001-0011-0010 expressed in binary coded decimal. To convert binary to BCD you can either design an incredibly complicated logic circuit to preform the operation, use a read-only memory (ROM) to output the correct values or use the method I chose of using an Arduino to do the conversion.

My friend and I created an Arduino sketch that takes an 8-bit input (0-255) and outputs 3 BCD digits. The output goes to a 3-digit Numitron readout board that I spent a good amount of time on.

3 Digit Numitron Readout


 

16 Responses to The Display

  1. Andrew says:

    That is very cool.

    I picked up some of those a few years ago from an EBay seller in Russia. I haven’t gotten around to using them yet but I thought they would look awesome on an 8-Bit Cosmac Elf computer or a TTL CPU project.

    I’ll check back later and see how your project shapes up.

    Andrew

  2. Kyle says:

    I like them a lot. I originally bought some similar VFD Numitron tubes from eBay and soon learned that driving 30 volts using 5 volt TTL logic would take far too much time and space on my computer. It’s too bad though, they glowed a brilliant iridescent blue. Did you get IV-9′s? If you get the chance, use them. They are very easy to work with and are straight forward in operation.

    • Andrew says:

      Yup, I’m just looking at them now. They are IV-9′s… They look about as easy to work with as a 7-Segment LED display but way cooler retro look.

  3. Kyle says:

    You bet. I wish that they still manufactured Numitron tubes today, they make such cool displays. Although perhaps their scarcity is what makes them so interesting.

  4. Hi there, You have done a great job. I will certainly digg it and for my part suggest to my friends. I’m sure they’ll be benefited from this website.

  5. [...] He’s aiming for the final product to have a bit of a steampunk aesthetic, including a steampunk case, and an already built Numitron tube display. [...]

  6. [...] He’s aiming for the final product to have a bit of a steampunk aesthetic, including a steampunk case, and an already built Numitron tube display. [...]

  7. [...] He’s aiming for the final product to have a bit of a steampunk aesthetic, including a steampunk case, and an already built Numitron tube display. [...]

  8. [...] He’s aiming for the final product to have a bit of a steampunk aesthetic, including a steampunk case, and an already built Numitron tube spectacle. [...]

  9. [...] He’s aiming for the final product to have a bit of a steampunk aesthetic, including a steampunk case, and an already built Numitron tube display. [...]

  10. Agneepath says:

    I’ll check back later and see how your project shapes up.

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  12. Themes says:

    In the second paragraph you have a typo. You have written “132 (1000 0010)” but it must be “132 (1000 0100)”

    Thanks for sharing your awesome project.

  13. js says:

    Was 74185 not available, since you decided to put a much more complicated processor to drive the display?

  14. js says:

    I mean this chip – datasheet:
    http://www.utm.edu/staff/leeb/DM74185.pdf

    and one vendor that claims to stock it: http://www.littlediode.com/components/74158.html

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