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
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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
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.
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.
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.
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.
[…] 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. […]
[…] 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. […]
[…] 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. […]
[…] 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. […]
[…] 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. […]
I’ll check back later and see how your project shapes up.
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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.
Thank you kindly for the correction, I changed it to the correct value. And I’m glad that you enjoyed my project.
Was 74185 not available, since you decided to put a much more complicated processor to drive the display?
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
Hey , How did u compiled this code? how did you use those functions ? are they predefined somewhere. how can this code work ?