If I had nothing but time, I would build a relay based finite state machine to
be the calculator.
It would probably take a relay rack or two of relays. Even super tiny pcb
mount relays would take some considerable room when you are chaining up half
adders etc.
I think some guy did this and built an 8080 CPU with relays.
Back when I was considerably younger I enjoyed the sound of a North Electric
relay panel interrogating a phone line to figure which person on the party line
was making the call and then sending the digits via MF tones. You could
diagnose the health of the machine by the sounds.
From: Dave
Sent: Monday, July 23, 2018 1:38 PM
To: af@af.afmug.com
Subject: Re: [AFMUG] OT Nixie tubes
Dont get too complex until you have a functional calculator :)
Sounds like a fun project vs my Galaga upright arcade restoration :)
I also came across some Gas Filled 4x12" Displays that are dot matrix.
They use 94V to power the Element.
On 07/21/2018 04:04 PM, Chuck McCown wrote:
Yes, I just found a source of old typewriter keys. I think I will connect
them to microswitches for a nice tactile feedback.
Analog volt meter showing the capacitor voltage. Will probably need a
voltage doubler to get up to the 180 volts needed for the nixie tubes.
Things start to dim, crank the crank a few turns.
Do I want to use cloth covered wire and solder terminal sockets. At some
point PCBs will have to be used. So I will probably get lazy and make a PCB
for everything.
Be fun to have some kind of mechanical annunciator showing the sign of the
exponent.
Prepper calculator. (Probably a raspberry pi in its heart).
Maybe use a telephone ringer bell to announce the result. I could add some
delay with the nixie tubes scrolling through the digits and one by one stopping
on the digits of the solution.
From: Chuck Macenski
Sent: Saturday, July 21, 2018 2:50 PM
To: af@af.afmug.com
Subject: Re: [AFMUG] OT Nixie tubes
Old silver and black typewriter keys. Think Enigma machine...
On Sat, Jul 21, 2018 at 3:28 PM Chuck McCown <ch...@wbmfg.com> wrote:
I must be nuts.
I am working on a calculator project that uses nixie tubes for a display.
I want to use a telephone magneto to charge up a cap to run the thing.
Kinda a steam punk RPN HP type of calculator.
I am stuck on what to use for buttons. I am thinking elevator buttons.
Large oak case. Just crank it for 10 seconds and then do your calculation.
I am also conflicted as to how many buttons.
Square and square root for sure.
Undecided about log, trig functions and whether or not to have scientific
notation. I think I will.
How many digits to display? Probably 5. Engineering mode only. 3 dot 2
display.
Also considering multiple lines to show 4 levels of the stack but I doubt I
will actually do that.
The question is: will I ever finish this thing?
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