From Antique Typewriter to a Functional Teletype, Called NVictria

July 2023

The NVictria TTY project involves the melding of 2 typewriters.

First an Old Remington No7 circa 1903, fire damaged, soot covered and rusty, jammed up. Pretty much a goner.

The second a more "modern" working 1980's electronic typewriter a Sharp PA-3000.

This is the amalgamation of the two. The end result... a 1903 typewriter reborn as a Teletype terminal with 12 digit 14 segment VFD display and the option for either using the original typewriter keys or a detached remote PS/2 keyboard. This peripheral becomes my printer / terminal adding to my already existing Cosmac VIP/ELF computer project listed below .

link to Cosmac Vip project video here.

https://www.youtube.com/watch?v=LUVBLWlYrJY

another here.

https://www.youtube.com/watch?v=z010E298Q2Q

300N71 baud ? What--Why?

The TTY communicates via 300 Baud serial line. The reason for this slow baud rate is due to the main computer it connects to is a "reborn" Cosmac VIP computer based on the RCA CDP-1802 CMOS cpu. Also known as the Cosmac ELF. In its operating system it has a utility program called UT4, no flow control, snail pace speed unfortunately.

I started by stripping down the Remington to the bare frame, (as seen in the photos) removing the platen, key strikes, keyboard. Adding a stepper motor for the carriage, motor for the line feed, new platen as the original was to short in width. CNC cut new key stems/ levers, added LED lights under each key cap. The leds light up when either the Keyboard key is pressed or the incoming serial data matches the letter / function sent.

The TTY (NVictria) can operate in either Typewriter mode ( just like an electronic typewriter) " local " or as an old school Teletype " remote ".

** NVictria Teletype Youtube video here, https://www.youtube.com/watch?v=n57a-BLW3nY

Other videos regarding this project

** Telnet. https://www.youtube.com/watch?v=oqWliWcpmSE

** Speech with the SPO256 Narrator chip set. https://www.youtube.com/watch?v=tPjZuh_XoIQ

** How I came up with the name NVictria. https://www.youtube.com/watch?v=dYVcgb8mGtg

** Victorian Teletype. https://www.youtube.com/watch?v=rHheyAU43cs

** Ascii art example. https://www.youtube.com/watch?v=jG8PYx-4Ugw

** Another talking chip the rare SPO264. https://www.youtube.com/watch?v=FGHIrmMiyp8

** close look at the FLAT screen CRTs. https://www.youtube.com/watch?v=9s5nEjI90rM

** Tachyscope 1.0 POV display unit. https://www.youtube.com/watch?v=4xrWhKwWYcc

will post Arduino ATmega .ino code / files at end of project

The electronics are split into 4 Arduino's systems. Atmega328 #1 (U7) is used for emulating the Sharp keyboard , 2nd for PS/2 keyscan and serial communications circuit (U5) , 3rd for serial to keycap leds (U14) , and 4th for serial to VFD control (U6) .

Sometime down the road I will combine some Arduino functions to reduce the qty from 4. ( programming is not my...."forte" .

Sharp keyboard matrix logic. I use (2) 4051 cmos 8- channel Analog multiplexers for doing the "key pressed " logic. (U9, U10). The U7 arduino takes serial incoming data and converts said data via lookup table to my version of a 8 bit word, that byte is sent out on i/o pins to the 2 multiplexers, giving me an X-Y axis for what key to "press". Refer to INO code for U7 .

Having reversed engineer the Sharp typewriter PCB, I then moved all necessary parts to my PCB, see Sharp Schematic page 3. Note that the schematic shows the use of 4066 rather than 4051, result is the same, better performance with the 4051s. (4066) was an earlier attempt.

PCBs. I first draw out a schematic with a free drawing program (TinyCad) https://www.tinycad.net then produce a scaled printable overlay that is then glued to a fiberglass or equivalent insulating board. Drill then mount all the components, and then the point to point wiring with wire-wrap wire. In this case for the TTY I went through 3 revisions of PCB designs , first two hand wired the final version Ver 3.0 I used Kicad had the board produced by PCBway.com.

Side note, I love lights.. everything I build has some kind in visual indicators, like to see what going on in the circuit, not just for debugging but entetainment.. all this just to bring your attention to the 2 alphanumeric led displays on the main board Dis1 and Dis2. They display the MSB and LSB of the 8 bit word sent to the 4051's aka SHARP keyboard matrix.

This TTY project has 4 circuit boards.

** PBC 1 and 2 are located at the rear of the TTY, farely large 4.5" x 9.5" with EDGE connector, MPB1 and PSU 1 boards

** Keycap Led driver PCB. Arduino U14 sends Data and CLK to a pair of HC595 shift registers to decode and drive the Keycap leds. the PCB dimensions are approx 2.25" x 7".

** Keyboard scan PCB. Using a donor PS/2 keyboard for its SCAN ic, after figuring out its key matrix layout I create a copper PCB with Mini PB switches all lined up in a row that will "live" or be located underneath each key strike arm. These neat little switches also offer a tactile feed back to confirm key presses. This is the only "home made" etched PCB on the TTY, the others are point to point wiring or as in the Main PCB a custom made from PCBway.

What does one do when a CNC is required... but don't have one... you build one of course. ( maybe another Instructable down the road?)

Then the fun begins. I needed to cut 4 types of keystems for the 4 rows of keys. Once done a quick sanding and polish.

Adding the Key cap and Led to the stem. Next up the Key cap lettering and lens.

I made use of my new CNC to also do the engraving to plexy cover plates and Space bar logo.

VFD tube scavenged from an old donor Satellite receiver. I removed the SN75518 ic and the Itron FG1211 VFD tube from the Satellite PCB. Afixed the SN75518 to the back of the Itron tube, connected the 9 wires back to the Main control board on the TTY. Filament AC power supplied by 120vac to 6 volt ac transformer with center tap.

ATmega (U6) receives serial data on pin2, looks up the the specific character map (custom to this display "Itron GF1211) and sends shift data to the SN75518 via i/o pin 11,12,13, Clock, Data, Latch, also data is sent to the Remote VFD display via i/o on pins 27 and 28, i2c Data and Clock

Steam Punk without brass is like cake without icing. A few parts in this build are brass, here are two switch plates. The left side one has 2 old school toggle switches, the right side has 6 push button functions that are on the PS/2 keyboard but had no room on the Remingtons, I added them to the right side of the TTY.

Making the "mask" for etching involved creating a diagram ( positive or negative) depending on what "look" I was goin for then on Inkscape, printing in mirror image, I use NAIL POLISH remover to transfer the laser toner to the brass plate. Let the brass etch for any where from a few minutes to 1/2 hour depending on age of etchant, outdoor temperature and how deep an etch I want.

Speech is generated from an SPO256-AL2 and the CTS256-AL2 (Text to Speech) rom.

The CTS256 accepts Serial coms at 300 baud. I added 2K of ram some latches and an audio amp. Of course 3 digit hex displays for good measure.

The last 2 photos show the "horn" type speaker front and rear views.

This remote display aka Desk lamp has qty of 12 x 16 segment VFD tubes part # IV-4 and uses qty of 2 of the HT16K33 back pack LED driver chip U1-1 and U1-2. I also use and ATmega 328 (U8) for Serial to I2C conversion. ( see WarmCat)

Side note, the 2nd to last photo shows that I purchased the VFD tubes from a seller named VANNAMORE in June 2021 located in Ukraine.This seller was fantastic , he gifted me extra smaller tubes because some of the larger VFD tubes where a bit weak. All the tubes worked great, A million thanks Vannamore, Слава Україні!

Side note 2, The last photo, I use (2) HT16K33 led driver ics each controlling 6 VFD tubes, and the code used in the ATmega 328 is by WarmCat link here https://github.com/WarmCatUK/WarmCat_6x14Backpack

Following Arduinos located on MAIN PCB

Code for U5, PS/2 to serial

Code for U6, serial to VFD

Code for U7, serial to TTY keyboard

Code for U14, serial to Keycap leds

Below is the code for remote VFD display ( IV-4 tubes)

Code for U8, serial to i2c, Warmcat

This is not so much an "HOW to DO" but rather a "How I did it". There are many parts to this project that glanced over, if there are any details or printed material that is difficult to read or you would like more info about please let me know via the comments section here.

I am not a programmer so please keep that in mind when you, and will find mistakes in the coding.

If you do "upgrade my code" / streamline it, please let me know more than glad to incorporate it in this project.

I'm recently retired and started this project as a pastime, It's all consuming. lol.

A few future ideas for this project are,

Remember the Victrola crank record player, well Edison made a cylindrical dictating machine that recorded audio to a "tube like" media. My next venture is to kinda use that idea but use as a base this thing called DICTABELT, and record ( save) my Cosmac Vip files ( audio based) aka old school cassette to this transparent blue plastic "belt". The idea is to engrave or encode audio to the Dictabelt record as single tracks to store my programs on. Inessence to use a "LP record" as my audio files medium, currently I save my audio files ( programs) as a MP3 on the laptop.

Another future project is adding CORE MEMORY to my Cosmac Vip, I have a large NCR core memory pcb, that I'm gathering info and parts in order to have it store data from the CDP1802 cpu. I see online there are small kits you can get, but they are only a few BITS, Id like something thats 8 bits wide by ....

Thanks for your time.

Daniel Ross