VCF-MW 9.0 COSMAC Exhibit

Last updated Mar 8 2015. Edited by Herb Johnson, (c) Herb Johnson Contact Herb at, an email address is on that page.


The purpose of this Web page, is to describe plans for, and the content of, a COSMAC exhibit at VCF-Midwest for September 13-14 2014. This is explained on this page, with item photos and Web links to more information. The exhibit was initally discussed with Josh Bensadon, who developed the COSMAC exhibit layout; in discussions with Dave Ruske, followed by discussions with Lee Hart, Bill Rowe and Herb Johnson. The bulk of COSMAC artifacts are from Josh, many from Dave, and items from Lee and Bill. This Web page is edited and published by Herb Johnson, with participants providing content, and bio and contact information. - Herb

COSMAC Exhibit at VCF-MW 9.0

This COSMAC exhibit was part of VCFMW 9.0 or VCF MidWest 9, September 13-14 2014, in Lombard, IL. West of Chicago in Lombard, IL, and part of the Fall Commodore Expo/ECCC. The event occurred and apparently went well, by all accounts. Their Web site includes links to photos and videos.

The COSMAC 1802 processor

RCA COSMAC 1802 Microprocessor. Famously known as the heart of the August 1976 Popular Electronics Microcomputer project article "THE COSMAC 'ELF'". Also used in the Galileo Spacecraft, however, those samples are lost in space. - Josh

The COSMAC microprocessor was first developed as a conceptual design in discrete (small scale) TTL logic in the early 1970's by Joseph Weisbecker and several of his RCA colleagues. A two-chip version was developed by RCA's Solid State Division in 1973-4, and a single chip version soon thereafter. I cover early COSMAC development on another Web page. This exhibit shows some of the earliest use of the COSMAC, by RCA in various development tools, in commercial use, as consumer video games, as vintage and current hobby microcomputer kits. They are all based on the early COSMAC 1802, and many based on the original ELF or VIP of the 1970's. - Herb

Exhibit plan and results

Exhibit layout before (by Josh) ...

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...and exhibit photos during (courtesy of Bill Rowe)

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Josh describes the final setup: "Our table was laid out as follows (from left to right on the time line scheme):

COSMAC ELF; RCA Studio II; RCA VIP,; ELF II,; Super ELF,; ACE computer;COMX 35, ;VELF ;ELF2K,; 1802 MC cards, Olduino

On the back board, a large poster of the 1802 die, posters of what $80 buys you in '76 and 2014, pictures of various ELF's and Galileo, Scrolling LED sign, COSMAC Development System Front Panel, Lee's wonderful model of the Galileo complete with 1802 flashing out the Arecibo message, a collection of various 1802, 1804, 1805 and 1806 processors. - Josh
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Josh, after the event: "First and foremost, Thanks [to the COSMAC exhibitors] for coming out and the opportunity to meet you all (including Herb [in April] at VCF-East)."

"Your interests and talents are all diverse and extensive but it's a pleasure to see them overlap within the 40 pins of the 1802. There was a lot of chatting with visitors and other exhibitors, it's amazing to see everyone chatting about this little chip."

"Thank you for being there and helping to chat up the display, we had enough visitors that kept us all very busy at times. I believe we did a wonderful job as a group, much stronger than [as] individuals. Looking back, I wished I had done a little more here and there, and we even missed all the presentations in the cafe. There is just a lot to do and it's not possible to see/do it all." - Josh

Lee Hart describes the event

"I had a ball! It's the first computer Faire I've been to in at least 10 years; probably more like 20. I guess I should get out more. Given that this was largely a 6502-centric crowd, I think we gave the lil' ol' 1802 an impressive show." Lee guessed attendence at 300-400 people; and that many must have driven in from out-of-state.

About the COSMAC: "Of the hundred or so people I spoke to, mosth people had never heard of the 1802. But a surprising number had fond memories of it. I've never seen such a wide range of 1802 systems in one place. All of them working and doing things, too. There were examples running machine language, BASIC, FORTH, and C programs."

Lee's impressions about other computers: "Besides Commodore, there were lots of Ataris, Amiga, Apple IIs of various flavors. Lots of PCs; some parts, some working. Also; There were at least two Don Lancaster TVTs at the show. One very nicely built, though not working. The other was a a later one (TVT-6 I think), and it was working!

There were a couple hundred [computers] in the room we were in; and there were 3 rooms, plus the cafe area, plus lots more "overflow" in the halls. And as fast as something got sold, people went out to their car and brought *more* in! Some of the 'really big' stuff was only exhibited in the parking lot - too big to move."

"By coincidence, the organizers of VCFMW had an "Arecibo challenge" contest at the door. How small a program can you write to send the message? We had that one NAILED with the Galileo model! Too bad there wasn't a prize." [Note from Herb: it was not quite a coincidence. Check the Web page about the COSMAC Arecibo program for details.]

"I also got to meet many people I had only known as names on the email lists. Besides Josh, Dave, and Bill, I also met Jack Rubin, Chris Elmquist, Christopher Bachmann, and many others! It is *so* much better to talk to folks face-to-face. Many MANY thanks to all of you for encouraging me to go. It was so much fun that I'll probably do it again next year." - Lee Hart

Here are Bill's photos from the event, on Facebook. Also, here are Dave's photos from the event, on flickr. And here's Josh's photos on cosmacelf (which you have to join to access).

Items exhibited (or planned to)

COSMAC MicroTutor 1974 (photo only)


This was a 1974-5 low-cost kit offered by RCA for COSMAC microprocessor development. There's no ROM, only RAM and toggle-in programming. Joseph Weisbecker, COSMAC processor developer (and game designer) tried to make microcomputers assessable to hobbyists and educators, as an exercise in programming, logic, games and puzzles. A later version was the COSMAC ELF, published in Popular Electronics in Aug 1976. This image is courtesy of The Sarnoff Collection, The College of New Jersey I hoped to bring one to exhibit, but plans and a loaned MicroTutor did not materialize. - Herb

RCA COSMAC Microtutor kit
My Web page about the earliest COSMAC processors and kits.
Contact me about a copy of the MicroTutor manual.



As photographed, this unit was completed by Josh Bensadon in August 2014. (Dave also brought an ELF to display, apparently it was built in the 1970's.) Josh's unit is a replica from the COSMAC ELF construction article from the Aug 1976 and later issues of Popular Electronics magazine. As displayed: " per original article. Functional, but not running any demo program. Behind it were 7 issues of Popular Electronics containing the 4 parts of the original articles and 3 extra articles. - Josh". Dave also brought an ELF to display, apparently it was built in the 1970's.

COSMAC Development System (front panel shown at VCF-MW)


Josh Bensadon's RCA brand COSMAC Development System, consisting of rackmount chassis with three COSMAC boards as shown. Looks like the single-chip 1802 CPU. Josh Bensadon has more photos of this at the Yahoo cosmacelf Web site. They show boards with 1977 date codes, and one board identified as "CDP18S509". - Herb

RCA Micromonitor in briefcase


RCA Micromonitor development kit with docs, from Josh. Photo by Dave Ruske at event.

Studio II 1977


RCA's video game computer. As displayed: "RCA Studio II, mostly running the built in game, but additional cartridges were available. It got a fair bit of interest because of it's attractive design." - Josh .

VIP of 1977


VIP was an RCA COSMAC product, a single board for development with video graphics. Owned by Josh Bensadon, photo by Bill Rowe at event. As displayed: "Running the Pixie Graphics Starship program, not a lot of interest here, but I would play data tapes for visitors that have never heard the tones and noise of a data tape." - Josh

ACE with keyboard


Here’s a photo of the ACE system [with Sanders brand keyboard]. Most of the ACE circuitry and the EPROM monitor program was published in Ipso Facto.. This particular system had a strange evolution and a crude encounter with a hacksaw. I wrote up the ACE story along with some photos of the boards and the keyboard [at this linked Web page].

The Sanders 720 keyboard is the keyboard with the blue keycaps in the photo of the ACE computer; it’s part of that system, and otherwise unrelated to the 1802. The keyboard was surplus I picked up from Poly Paks (I think) and comes from a Sanders 720 data display, and is all discrete diodes inside. - Dave

As displayed: " the Tardis case. There was a lot of complements on Dave's workmanship... that case sparkled like a diamond!" - Josh

ELF II 1978


The Netronics ELF II was an early COSMAC microcomputer trainer kit. Photo by Bill Rowe at event. As displayed: " Didn't get it running until the 2nd day, not a lot of interest." - Josh

Super ELF 1978


Photo of Josh's SuperELF, in operation just before the event. "I'm using a small 3" camera monitor. It can save & load to cassette, but I'm using my laptop at the moment to save/load through the audio port with Audacity." - Josh. As displayed: "not running until late the 1st day, power supply connector issue. There was more interest in the monitor I used for it, which was a Sony Camera Monitor used for professional studio camera's (complete with red light on top for 'LIVE' camera indication). " - Josh

Galileo spacecraft and COSMAC - launched 1989, modeled 2014

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(photos left and right by Lee Hart). Built by Lee Hart for this exhibit, as a "tribute spacecraft" exhibit with an 1802 Membership Card, to "broadcast" a message into space. Many early amateur and research spacecraft also used the 1802 because of its low power, high logic thresholds, and CMOS/ceramic resistance to radiation. It's likely the first microprocessor to go into space.

The Galileo spacecraft to Jupiter used multiple 1802's; Lee built the model from photos and basic materials - metal, copper PC boards, fabric. It "broadcasts" in light and beeps, the message sent decades ago through a powerful radio telescope on Earth, at Arecibo. Here's a Web page with Lee's progress reports on his "build". There's also links on that page, about the Arecibo message and 1802 program in use. [vcfmw] [vcfmw]

Photo on left by Dave, and on the right by Josh, are of the model on exhibit. Text by Lee Hart below it says: "The GALILEO - Used six 1802 microcomputers to explore Jupiter and its moons. This model has just one 1802A. It is sending the Arecibo binary message. Program *and* data is just 256 bytes. Power consumption is only 0.25mA (plus LED current). ;)"

This is not the Arecibo message from Lee's model: "All these microprocessors are yours except this one. Attempt no long integers. Use them with Tiny BASIC. Use them in PL/M." - Herb

ComX 35 of 1983

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Josh's COMX35 with expansion boxes and cards (left) and a SRAM mod (right). The SRAM is a fix to troublesome DRAM. As displayed: "..could not operate because of incompatible VGA monitor and the PAL-to-VGA converter." - Josh

VELF of 2003


Computer that operates as both VIP and ELF, home brew by Josh Bensadon. As displayed: "..(my homebrew computer) connected to a 7" TFT monitor, running John Conway's game of Life" - Josh

ELF2K 2006


Here’s my ELF 2K system, though I don’t know for certain whether my system or Josh’s will end up on display: Josh’s ELF 2K has the hex pad. This has the disk/UART/RTC daughter board, but it’s mounted beneath the main board to avoid obscuring the display. That gives it 256 MB of flash storage running Mike Riley’s ELF OS ( ). - Dave

As displayed: "..connected to an RCA VP-4801 dumb terminal, running a demo program written by Dave in Forth." - Josh

VP4801 terminal

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Josh: "I've powered up the VP4801, it works! 40 or 80 columns, RS-232 still needs to be tested, I need to build a power supply for it. Interesting design, they used a 1F super capacitor to hold memory. The newest chips are from 1984. The date on the back is "4444", what ever that means?". Josh provided this info on the power supply for the VP-4801. It's a wall-wart transformer with two windings: 10VDC 750Ma (split winding with two diodes), and 14/14V AC 133Ma, RCA branded.

Lee Hart and the COSMAC "Membership Card" 2009 forward

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Membership Card kit - modern version of 1976 COSMAC 1802 ELF kit. Available as a kit since 2009. Front panel to load programs, RAM and ROM, serial interface, front cover cards. Fits in an Altoids can! (the photo has a second can for a power supply). See the support Web page for the 1802 Membership card and links to purchase one.

[vcfmw] For fun, Lee Hart designed a simpler COSMAC 1802 board, just to randomly run "instructions" and display "results" as an LED face - called Face Card. Photo by Lee Hart. It's also available as a simple to assemble kit.

As displayed: "... built and in kits, plus a paper stand for take-away sheets, plus Olduino set up with a laptop playing Bagles, T-Shirts, Christmas Tree kits." - Josh

Olduino Interface Board

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"The Olduino is a retro-computing version of Arduino. It uses a 1970's 1802 processor of the Membership Card, but can be programmed in C and can use Arduino-compatible shields and peripherals. I will be demonstrating the Olduino in an ultrasonic rangefinder and other applications. For more information visit my olduino Web site" - Bill Rowe

As exhibited: "Olduino set up with a laptop playing Bagles." - Josh

Biographies and contact info

Dave Ruske of cosmacelf


Here are Dave's photos from the event.

Dave says: "In high school Dave purchased a Netronics ELF II kit, using it to work though Tom Pittman's "A Short Course in Programming". He worked 2 years repairing a variety of computers for Xerox, then received a life-changing invitation to join a software startup named ICOM, which would later become a cornerstone of Rockwell Automation's software business. Now a software geek, in 2001 something possessed him to write a an ELF emulator in Forth on a Palm PDA, and to create the website and the Yahoo discussion forum to support it. He has since created an ELF emulator for OS X and occasionally still tinkers with 1802-based computers, just for fun."

Lee Hart of TMSI

Lee Hart was a digital engineer in the 1970's when a COSMAC MicroKit and MicroTutor were shown to him by a RCA "field rep". His big-company bosses wouldn't buy COSMACs. But the low-power noise-resistant CMOS product held his interest. In 1978 he started his own digital design company, to make a COSMAC controller called "BASYS". He's designed microprocessor and digital products ever since.

Four decades later, COSMAC enthusiasts at cosmacelf (and myself) knudged him to produce a modern ELF (and Microtutor) called the Membership Card. Five years later, they are still available today. Web support is at the home page for the 1802 Membership Card at The card is sold by Lee Hart from the Membership Card Web sales page at Lee's site. Lee is an accomplished electric vehicle owner, power-train designer and developer, a founder of the Sunrise EV2 Project.

Josh Bensadon

Josh built a COSMAC ELF in 1978 during junior high and hand-programmed it in machine code. Later with an EET degree, he worked on PC-compatible systems and a variety of 8-bit processors (8051, Z80, PIC); he published a PIC article in Nuts & Volts. About a decade ago he rediscovered some VIP Game Manuals and resurrected his interest in the 1802, Josh joined the COSMAC ELF yahoo group, and designed & built the VELF. While collecting other vintage computer systems, he's preparing this ELF/1802 exhibit. Non related interests are "Fostering of Kittens, Back yard Mechanic, Cycling, WWI and WWII history". (Edited notes from Josh)

Bill Rowe


Here are Bill's photos from the event, on Facebook.

"I built my first home computer in the 1970's from the Popular Electronics article. I got out of hardware hacking in the 1980's but came back when somebody gave me an Arduino in 2008. When Lee Hart made the little Membership Card I thought "Hmmm Olduino?" The Olduino has been through several generations of hardware and software and boasts its own C compiler. I have enough development plans to keep the project going for a while." - Bill Rowe


Herb Johnson of


(Herb edited, published and Web-hosted this Web page, but did not exhibit items or attend the event.)

I do a lot about restoring and preserving micro computers of the 70's and 80's. I've provided support for Lee Hart's 1802 Membership Card project for several years. Along the way, I've researched RCA COSMAC history, including in space, and early RCA development products. I assisted a museum's collection of RCA with their COSMAC artifacts. Contact Herb at, an email address is available on that page..

Editorial: The context of the exhibit, and consequences

Some of this material was taken from Herb Johnson's VCF-E 9.0 exhibit of COSMAC and early Intel products. - Herb Johnson

What is this exhibit about?

The COSMAC 1802 microprocessor and its engineering and gaming products, have always drawn interest from people who want to work with binary-level programming and with gaming. Generations of binary-level ELF computers were, and are, in hobby production. And a subset of people who want to put modern "tech" on vintage micros, have also put them on COSMACs.

How were these early microprocessor development tools used? What was made from them?

You built other devices for them to control and measure, and you wrote the programs to do that. You wrote the programs in binary, or hand-assembled code. Or you could "play" simple games, or treat programming as a game. The MicroTutor manual on display had some textual examples, toggle-in programs. Few people could program a prom in 1975. Later with program storage on paper tape or cassettes, you could store programs and data. With a terminal and more memory, you could run like a then-conventional computer could, but without punched cards and waiting a day for results!

But how was it done first? By the engineers and techs, who had these tools, on their company's budgets or in their college labs. They had the earliest microprocessors and the austere development environments for them. Or none! They programmed in binary! They hand-assembled! Stored data in ROMs and punched tape, or just toggled it in.

What was microcomputing like in the 1970's?


The early COSMAC kits, like the Elf of the mid-1970's, represented the earliest, minimalist kinds of development tools or demonstrations. Few had access to any computing or even electronic resources. Later products, like the VIP, and the COSMAC Development System, represented development systems for those with access to PROM programmers, paper-tape (audio cassette later on), and computers to run cross-assemblers and compilers. The Studio II represented RCA's home video game product. RCA as a corporation did not have a focused strategy or product line for micro-computers, because of failed business decisions about RCA's mainframe computer product.

Later in the 1970's, more expensive personal computers were produced by many small compainies for home-office, industrial control, and small business use. (RCA produced some board-level controller products, or designs.) Just before and in the 1980's, many home video gaming systems were produced by many compaines small and large. In fact there was a video-game market "crash" in the later 80's, from too many products. Some microcomputers claimed to do both - gaming and computing.

Companies were created to support all these activities, and there were hundreds of personal computer brands and products and services for them all. With the IBM PC introduction in 1981, most of these companies, products and people, moved to support the IBM PC. But many microcomputers of the 70's were in use for years after; and microprocessor hobby products, and some microcomputer brands, survived and continued into the 1990's.

Where can I learn more about 1970's microcomputing?

Books and magazines from the mid 1970's, represented both "TTL logic" hobby activities and the earliest microcomputing activities. Many period magazines in electronics and ham radio, jumped on the microcomputer revolution and expanded, then competed with new computer magazines like BYTE and Kilobaud, Dr. Dobb's Journal, etc. Here's a list of mid-1970's mags and books I had available at another exhibit I did on that era. The ad sheet for PolyPaks was from Aug 1975 which ran in a number of electronic magazines. - Herb Johnson

73 Magazine for Aug 1975 selected pages
73 Mag for Apr 1975 selected pages
Radio Electronics for Apr 1975
PolyPaks ad for Aug 1975
The Bugbook I - Logic and Memory Experiments, 1975
TTL Cookbook, Don Lancaster, 1976
An Introduction to Microcomputers, Adam Osborne, 1976

What did things "cost" in the 1970's?

$1 in 1975 = $4 in 2014. But many expensive items in the 70's, became cheap when commercially produced, and cheaper still with automated production (thanks to the microprocessor).

a 1975 Chevy Nova sedan? about $3K-$4K
gasoline? 30 to 50 cents a gallon
a color TV? maybe $750
a term at state college, room & food? $5-600
Jan 1975 average US home price? about $40K
median household income? about $10K year
Engineering starting salaries? $12K-18K year

1802 processor - $???; 8080 processor was hundreds at first
1K bit RAM - $4-$5
256 byte PROM - $20
TTL chips - 2 to 5 for $1
typical digital logic-only kits - $hundreds, except the ELF was maybe $100 to build
* MITS Altair 8800 kit - $439 *

This page is copyright Herb Johnson (c) 2015. Some content on this page, belongs to the authors so named, and is used with their permission. Contact Herb at, an email address is available on that page..