Last updated: 20-Dec-2025, 05:29 AM AEST by Don McKenzie
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December 2023
The Australian Computer Museum Society (ACMS) reached out to me regarding my TRS-80 Model One, which appears to be the first true Personal Computer (PC) sold in Australia. This took place in March 1978. In light of its historical significance, I decided to donate it to ACMS, and they graciously accepted it.
I share the sentiment of Riley Perry, Curator of ACMS, regarding the classification of the first Personal Computers. To narrow it down, it was one of the three computers now regarded as the "1977 Trinity Computers": Commodore Pet, Apple 2, and TRS-80 Model One. In 1977, the average Australian wage was approximately $8,700 AUD per year.
In late 1977, when I placed my order for the TRS-80, my job title was "Totalisator Mechanic." My days were spent immersed in ink and grease, frequently necessitating hand washing anywhere from 10 to 20 times daily. As a blue-collar worker, this purchase marked the closest I would come to acquiring a Personal Computer for my own use, to be run from the comfort of my home. Despite the demanding hours I put in at ATL, the income it generated afforded me the opportunity to pursue my dream, and I didn't hesitate to seize it.
Jan-2024
An image from ACMS HQ starring a certain TRS-80 and full details, can be viewed by clicking on the link below:
Australia's First Personal Computer?
The significant black disk is known as a "Premier Odds Dividend Calculator." It's worth noting that the Powerhouse Museum (another donor), Steven Pass, and now the ACMS each possess one.
This device was primarily employed to compute the odds for win-place betting on horse races using the old electro-mechanical systems found in George Julius - ATL totalisator systems. Subsequently, the calculated "Odds" were exhibited via a series of cards within window panels at the front and typically upstairs in the main tote house. Some tracks also implemented a system of roller blinds managed by odds display personnel. On occasions when our administrative staff arrived late due to car breakdowns or similar mishaps, I had to operate the disk and post the Odds a couple of times.
Later iterations featured direct electro-mechanical connections from the horse adders to the odds displays. An excellent illustration of this was witnessed at Flemington Racecourse Paddock A, during the Melbourne Cup of 1931, which marked the inaugural cup utilizing the new ATL totalisator system.
I think we now have three classes of items.
Boards up to 1995, with boards marked as "Don McKenzie".
1996 and after. Boards by "Dontronics". The internet had arrived, and so had my new updated shopping cart.
I also had many people from all over the world, send me their babies, mainly Simmstick designs.
During the era of PC-XTs, PC-ATs, and their clones, the majority of input and output operations were carried out using either a DB-9 or a DB-25 connector. To address this need, I designed five compact DB boards that enthusiasts could assemble themselves at a minimal cost. These boards were indispensable for anyone working with RS-232 interfaces.
As for the number of units sold, this venture took place before 1996, and unfortunately, I have no records to provide insights into the sales figures. However, I'm hopeful that the text on the accompanying image provides a more detailed explanation of these boards.
One example is in the photo, second board from the right. These were sold through the Electronics Mags, as was any product prior to the Internet sales.
Let's delve into several boards at once, although I must admit, documentation on these is a bit sparse.
We've got the PIGMY, PIPEX, PPEX, and relay boards, all predating the Dontronics era. Among these are two boards roughly the size of a 3.5" floppy, sporting DB-25 connectors, along with a longer board featuring DB-25 connectors at each end. Additionally, there's a relay board without the relays. You should be able to spot these in the photo, along with the markings on the boards.
Back in the early days of PCs and clones, every I/O control board I produced interfaced through either the parallel or serial port.
For more details, you can visit:
Finding Files for old boards
As the term "microprocessor" was gradually being supplanted by "microcontroller", wherein the CPU, I/O, ROM, and RAM were integrated into a single chip, such as PICs, AVRs, and new products like Stamps became popular, new languages emerged to cater to these devices. Basic and Basic Pro, plus excellent C compilers for PICs and AVRs, and my boards were evolving to accommodate these changes.
And you can download all the old "Don McKenzie" files from:
Don-McKenzie-files-1978-1995.zip ▼
These files are generously provided by Alan Laughton from the Microbee Archives. Yes, I've had to hunt down my own original documentation.
Why bother with a full personal computer to control the external world when a single microcontroller and some simple interface logic would suffice?
In the 1980s, computers, including clones, typically featured DB-25 connectors at the back of the case for printer output.
I found it straightforward to create computer and printer switches based on the DB-25 pinouts in conjunction with my PBUFF board. Users asked for it, so I produced. The small board with the DB-25 connector and the toggle switch with a red toggle would likely be one of these two boards.
Locating documentation for these boards, along with others I designed and supplied before Dontronics, proved to be a real challenge. Unfortunately, I've simply forgotten most of it.
I think that covers all of the pre-Dontronics boards with the exception of PBUFF. That is the board with the black front panel and switches, with a ribbon cable attached.
PBUFF: That is the board with the black front panel and switches, with a ribbon cable attached.
A few years into the TRS-80, I designed a printer buffer based on the Z80. Printers of the day had no memory, so when you went to print a large document, your PC was completely tied up during the print. PBUFF was a printer buffer that could be configured from 8K to 4Mb of DRAM. Hardware memory interfacing was done with only a single 74LS00 and a 74LS04. The magic was achieved with software and no hardware multiplexing was used. To my knowledge, I am the only person that was able to achieve this result. PBUFF sold over 4000 units worldwide, well before the internet was known.
A very early board, single sided.
References:
Electronics Australia Magazine Apr-94
Silicon Chip Magazine Oct-89
Australian Electronics Jan-88 (PBUFF memory secrets revealed.)
Australian Electronics Mar-87
A later Rev K board.
PBUFF became the core for my other Z80 projects and was used for my ZLOAD development system, Moving Message Board, which was featured in four consecutive issues of Silicon Chip magazine, and my little Z80 to PDP 11-40 Front panel project.
I reconstructed 8080 Basic and developed what I termed Z8T Basic. With this, you could execute Z80 machine code or Z8T Basic on my ZLOAD board.
Additionally, I constructed a machine controller for my father's backyard operation, which manufactured spirit plumber's brushes. This machine was responsible for cutting and drilling a wooden dowel, trimming horsehair to the required length, and inserting it into the hole before stapling it to create the finished product.
My father configured the relays and solenoids to carry out these tasks, while I authored the program in Basic on a Z80.
I wrote in one of the magazines that I had sold over 4000 PBUFFs, yet I know I sold many more after that statement.
The package labeled Olimex houses a Duinomite - Mini. Near the PBUFF board, there are three more boards, square in shape, adorned with numerous black headers. These boards serve the purpose of adapting between the Duinomite and various standard Arduino configurations.
Our involvement extended to the Maximite project, masterminded by Geoff Graham in 2011. Geoff ingeniously blended MM-Basic software with hardware encased in a PIC chip, which piqued my interest following my experience with TRS-80 Basic.
The collaboration resulted in the creation of the Dontronics "Arduino" Duinomite. A screenshot from Silicon Chip edition Dec-2011 Page 61 shows dontronics.com overlaid on the images, accompanied by an article penned by Geoff Graham.
My colleague Mick Gulovsen and I devised a new hardware design for the Maximite, which was manufactured with the assistance of Tsvetan Usunov and his team at Olimex in Bulgaria. This design, christened Duinomite by Mick and pronounced "Dynamite" aimed to seamlessly integrate with Arduino-compatible headers, representing a significant effort on our part.
Tsvetan and his team at Olimex demonstrated professionalism and efficiency in production. However, their interpretation diverged significantly from my vision, necessitating the procurement of new software from a third party enlisted by Olimex to ensure Duinomite's compatibility with Maximite MM-Basic.
Regrettably, the third-party opted to assert full ownership over the work, even modifying the power-up message to showcase their credentials instead of Geoff's. As I found myself in Darwin Hospital at the time, I had limited control over the project's trajectory, leading me to disengage from Maximite. Nonetheless, as per my agreement with Olimex to retail Duinomite, I continued sales for some time.
Subsequently, Geoff authored a version tailored to run on the Duinomite, as documented in The Back Shed's Maximite article.
The Backshed-Maximite
Olimex.com-Duinomite
I reckon most of the items captured in the AMCS photo that haven't been covered, are Simmsticks, barring one exception.
That red board sporting a green ZIF socket must have been sent to me by someone keen on showcasing their PCB creation. I used to receive boards from all corners of the globe, whether folks wanted to share their projects with me or perhaps hoped for a chance to collaborate. I couldn't always spare the time to delve into each submission. Rather than tossing it aside, I figured someone at ACMS might find a use for it, or at least salvage the ZIF socket.
Another red board in the photo likely corresponds to a Simmstick design forwarded to me by someone in the community.
The world was shifting once more, from Microprocessors to Microcontrollers. Unlike their predecessors, Microcontrollers housed all the intelligence within a single chip. All you needed was a power supply and the appropriate I/O circuitry to control whatever you desired.
My Dontronics "DT" Simmsticks were undeniably my best-selling product. While I once quoted selling over 50K units in a magazine, the final tally remains a mystery to me. We boasted dealers worldwide and even hosted design contests. In 1999, we offered a $500USD first prize, followed by $1000USD in 2000.
The Simmstick originated from a 30-pin SIMM socket-based Single Board Computer crafted by Antti Lukats from Estonia. Initially designed for PIC16Cxx chips, it later expanded to support other Microcontroller families, such as Atmel devices.
We offered support boards for both Atmel AVR and non-AVR chips in both 20 and 40-pin configurations. The beauty of it lay in its compatibility with the common 30-pin DRAM SIMM socket, a staple on PC motherboards and clones like the PC-XT and PC-AT.
Facing supply issues from Antti, and with his blessing, I began developing my own line of "DT" Simmsticks. Recognizing the need for power supply modules, new motherboards, programmers, and I/O boards, I sought user feedback and swiftly responded with new designs. Our range grew to encompass small and large proto boards, CPU boards, motherboards, and various I/O modules. We even welcomed custom or third-party designs, fostering a vibrant community of innovation.
What set our Simmsticks apart was not just their versatility but also their affordability. Priced at around $6USD retail per bare PCB for single quantities, these boards were double-sided, plated through, and solder masked, measuring a slim 3.5" by 1" and a mere .05" thick. Moreover, we streamlined postage, often dispatching batches of 10 or 12 boards at standard letter rates, both locally and internationally. Our robust packaging, quantity discounts, and postage-free minimum order policy ensured minimal losses and maximum satisfaction for our customers.
Here are some links:
Simmstick General Overview
Dontronics Simmstick Listing
Simmstick Dealers and Re-Sellers
Index: Simmstick