Lee Hart's BASYS card and ITSABOT

This Web page discusses the COSMAC 1802-based BASYS card designed by Lee Hart in 1978, and a simple robot around it called ITSABOT. This note Last updated Dec 26 2017. Edited by Herb Johnson, (c) Herb Johnson


In the mid-1970's the RCA Laboratory in central New Jersey, now called the David Sarnoff Center, developed a line of CMOS integrated circuit chips, branded COSMOS. This led to an early microprocessor line around the 1802, RCA's CMOS microprocessor. The designer produced an 1802 kit which was simple enough to be built by hobbyists - a common practice in the era - called the ELF. Many generations of ELF computers were subsequently built, redesigned and sold, from the 1970's to the present day (2016).


Lee Hart built an ELF himself in the era. In 1978, years after seeing a RCA MicroTutor and MicroKit, Lee Hart designed and built for TMSI, a COSMAC 1802 based single board computer called BASYS. A photo is to the left on this Web page. It ran on almost no power - the serial line interface current could power the whole computer! Here's a photo of the serial interface module. This Web page discusses the BASYS product, some uses of it, its technology, and its successors.

BASYS and other work, led Lee Hart to a series of 1802 projects which he discusses in the linked document. In 2006, he prototyped a kind of "successor" to the BASIS and to the ELF, the 1802 "membership card" in an Altoids can. In 2009, he first offered a Membership Card kit; as of 2016 it's in Revision H2 and available on the linked Web page. - Herb Johnson

BASYS docs and software

Here's a TIF/PDF scan of my BASYS manual, permitted by Lee Hart/TMSI. Also, here's notes in the Tiny BASIC manual that I've abstracted for a brief hardware view of the BASYS. Here'sa higher-quality JPEG of the board schematic and of the interface schematic.

Lee Hart wrote a ROM monitor for the 1802, called "IDIOT", in 1982 for his BASYS product. He also provided it with a FORTH he called "8th". In this ZIP file, there's a collection of 8th versions, including the 8th V1.2 ROM binary in my [Herb Johnson's] BASYS board.

Lee obtained a Tiny BASIC from Tom Pittman and wrote a version for the 1802. The manual includes hardware information about the BASYS.

Another Lee Hart software tool for the 1802 was his 1802 version of Forth, which he called "8th". If you check that Web page, the ZIP file of 8th code includes the version 1.2 ROM image from my BASYS board. Here's a closer image of my BASYS board jumper areas.


Itsabot Itsabot

Lee Hart said in 2016: "There were of course lots of robots in the 70's remote-controlled by minicomputers. [Seymour Papert's book] "Mindstorms" came out in 1980, and was all about LOGO and turtle robots. Most of the computers in this early LOGO work were minis. There's a great story in "Hackers" about a PDP- mini being used to control a turtle robot. The teenage son of a college professor wrote a program to "see" where the robot was with a TV camera, drive the robot to an object, and then push it back to him.

Byte, Interface age, Dr. Dobbs etc. all had various articles on microcomputers and robotics. [My colleague] Jeff Duntemann built "Captain Cosmo", an 1802-based robot in the 1970's [which was featured in Look magazine]. All this inspired Itsabox.

Lee said: "My first 1802 robot was Itsabox (It's A Box turtle robot; get it?) It was a BASYS board driving two stepper motors for the left and right wheels, two toe switches to sense the edges of the table, and two finger switches to sense when it touched an object. There was also an RS-232 port, and a speaker to make noises. It was programmed in 8TH, and worked like the Logo turtle robots."

Lee continues: "This photo is of the first Itsabox, built around 1979 when I lived in Rochester NY. It went to the West Coast Computer Faire the year we had the booth across from Heathkit and their introduced Hero robot [probably 1982 - Herb]." The second Itsabox was built later (maybe 1982?) in Ann Arbor. It used gearmotors instead of the direct-drive stepmotors. It had a hand on the front, and 4 nicad D-cells instead of the big white lead-acid Gates battery. Otherwise, they both used BASYS boards, the same box, and were programmed in 8TH." - Lee Hart

Another version of the BASYS was mounted in a box, with a solderless breadboard on top; This was called Proteus, as in "prototypes". Lee compared 1802 products like BASYS and another of his designs called PROTEUS, to modern microcontrollers like the Microchip PIC.

A BASYS PROM programmer

In Oct 2017, Lee Hart shared with me, some notes on PROM programmers made for BASYS.

Some observations about BASYS

BASYS/1 - what a wonderful thing! posted by Bill Rowe in cosmacelf, May 10th 2013:

I don't know how many people have looked at the material on the BASYS card; but it's quite a wonderful thing. I know Lee posted a description of it once [in Yahoo cosmacelf] but I hadn't really looked at it. I was blown away when I did.

It was a single-board 1802 computer with rom and ram, serial and parallel I/O as well as 80 bits of multiplexed I/O and FSK audio. The card looks like about 3X5 so it's bigger than a membership card but it's not very big. Besides all the I/O built in there's a prototyping area for adding your own components. The manual is a masterpiece including schematics, assembly instructions, and theory of operation. You can see why Lee did such a good job on the Membership Card manual.

I guess it probably got used by professionals for embedded systems and prototyping. I think Lee mentioned that they're rare and go for $1000 or so today. If these had been cheap we'd have had the Arduino phenomenon a quarter century early! This is the original Olduino. - Bill Rowe

Lee responds: Wow; thanks Bill! That is quite a compliment!

The BASYS boards sold for about $129 each. There was a kit version, but we didn't sell very many. We never really did much marketing to hobbyists. I doubt any BASYS board has sold [on eBay] for $1000, but eBay is a crazy market.

The board was 4.5" x 6.5" with a 22/22 pin edge connector; a pretty common size at the time. It had the 1802, a crystal controlled clock, 4K EPROM socket, 2K of RAM, an 8-bit input and output port, and an optically isolated serial port. There was a circuit that used DMA to create 10 input and 10 output ports, so it could scan an 8-digit 7-segment display and 80-key keyboard in hardware (the LED segments and key switches appeared as bits in RAM). The I/O ports could also have 60v 0.5amp drivers for things like lights, motors, and relays. The idea of the BASYS board was that it could be connected to real-world loads directly; without the usual tangle of I/O board "shields" we take for granted today.

The little adapter board at the left in the photo is an accessory. It has a 5v regulator, 25-pin D-connector for an RS-232 interface, and simple 300-baud modem.

I occasionally wonder if I should make some more BASYS boards. But I don't really know if anyone would want one. - Lee Hart, 2012

Herb Johnson comments: A number of cosmacelf people expressed interest in a BASYS card. A few noted the RCA development boards, which are a bussed version of cards like the BASYS, go for hundreds of dollars on eBay.

Ipso Facto and BASYS, 8th

Dave Ruske of cosmacelf posted in May 2013: TMSI was one of Ipso Facto's few advertisers; see page 40 in issue 31 (October 1982), for instance in issue number 31 on the cosmacelf.com Web site. A BASYS/1 system with 1K of RAM in that ad sold for $149.50, which was pretty reasonable given the hardware it packed on board.

On a different but related topic, I notice that TMSI's 8TH lists in that ad for $100, which at first blush seems pretty steep, given that a free figForth for the 1802 was available by then. But an article by a certain L. A. Hart in Ipso Facto 29 (May 1982, "FORTH - A Bridge Over Troubled Waters," page 20) puts that in perspective in its conclusion: "Real FORTH is sold only by FORTH, Inc., for over $5,000. They have a toy version called picoFORTH to demonstrate it, but even it sells for $195."

Imagine: $5,000 for an 1802 Forth, in 1982 currency. According to the first inflation calculator Google turned up, that's close to $12,000 in today's currency! One has to wonder how many copies FORTH, Inc. sold. - Dave Ruske

BASYS owners recently

As noted, Lee Hart produces 1802 microcomputer kits today. As for robots: "At one time, I was going to build another ITSABOT. I collected all the original parts; a BASYS board, stepper motors, and even one of the original grey aluminum boxes that I built the first two in! Then I got distracted, so it sits..."I also bought a little R2D2 toy robot. The idea was to put an 1802 Membership Card inside, but it turns out there's no room. It would take a lot of machining to hollow it out enough to fit. And, its drive motor setup is extremely crude (as befits a toy). So it sits."

smiley smiley

"I have a couple other robots that are finished. One I call Smiley. Smiley was built in the mid-1980's. It uses just one IC (a 4093 quad 2-input gate) as its "brains". It drives two 1.5v clock motors. The wheels are driven by the minute hand of the clock mechanisms. It is powered with three small photovoltaic panels from old solar-powered calculators. It drives around seeking light, and positions itself under the brightest light source. [Whisker-wires in front and back, sense obstacles.]" - Lee Hart

Lee also built and kept, a wheeled platform with an RCA VIP [1802 microcomputer] to control it. As previously noted, today Lee Hart produces an 1802 Membership Card kit, available on the linked Web page.


Rod Kapela wrote to Lee Hart and I in 2012:

I used one of those computers to make my own robot back in 1983. [It has the form of a flower, and the computer is is in the pot or base.]

This flower was supposed to wait till there was enough light, then it would open it's petals then scan until it found the brightest spot. The antlers were four photodiodes, which controlled a motor to rotate around in the pot and a motor to move up and down. The flower and the leaves holds 11 three-inch solar cells which should be enough to charge 4 NiCad batteries.

The flower would track the sun until the batteries were recharged then would try making 'music' with 1 one bit digital to analog converter.

I've started to fix it up, but I no longer have the software that I wrote to run it. It was written in 8th, which does not seem to be documented anywhere. [I referred him to the 8th docs on this site - Herb]

I need to buy or make a USB to RS-232 converter to talk to the board, it's been a while since I had a serial port on a computer. Do you know the default speed of the serial port on the board? - Rod

Steward Marshall's BASYS boards are boxed by Steward, and shown on the ELF owner's show-and-tell Web section of cosmacelf.com. Look on the site for many other 1802 resources and history.

Related Web links

another archive of Lee's Hart's BASYS work on cosmacelf.com, including Tiny BASIC, is part of cosmacelf's software archives. There's a Yahoo disscussion group "cosmacelf" as well.

The Sarnoff's RCA COSMAC artifacts are now part of The Sarnoff Collection.

This page and edited content is copyright Herb Johnson (c) 2017, execept content written by Lee Hart or others. Contact Herb at www.retrotechnology.com, an email address is available on that page..