Inputs Of Interest: Canadian MCM/70 Was Kinda Like The First Cyberdeck

Not to start a debate in the comments or anything, but what would you say was the first microcomputer, or personal computer? We suppose the answer depends on your definition. Some would argue that the PC was born at Xerox PARC with a curious portrait-mode display and a three-button mouse, while others would say it all began in a garage in either Los Altos, California or Albuquerque, New Mexico.

If you take the term ‘computer’ to mean that which can crunch big numbers fairly quickly, then the Canadian-made MCM/70 is arguably the first personal computer in that it is portable, has an alphanumeric keyboard, a display, and supports cassette storage, which could be used to extend the 8K of memory. It was an all-in-one computing solution, and it could have an optional telephone modem built in. This was a forward-thinking machine for 1974.

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Audio Cassette Tape Data Retrospective

It has been a long time since we stored software and computer data on audiotape. But it used to be the de facto standard for hobby computers and [Noel] has a great video about the Amstrad’s system (embedded below) which was pretty typical and how the process could be sped up since today, you have perfect audio reproduction, especially compared to consumer-grade audiotape.

The cassette tapes suffered from several problems. The tape had an inherently low bandwidth, there was quite a bit of noise present from the analog circuitry and heads, and the transport speed wasn’t necessarily constant. However, you can easily digitally synthesize relatively noise-free sound at high fidelity and rock-solid frequency. So basically a microcontroller, like an Arduino, can look like an extremely high-quality tape drive.

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Atari Tape Drive Turned Security DVR

We know that a lot of our beloved readers don’t take kindly to abuse of vintage hardware, so the Atari fans in the audience may want to avert their eyes for this one. Especially if they’re particularly keen on spinning up their Jawbreaker cassette on authentic hardware, as [iot4c] has gutted an Atari XC12 Program Recorder to turn it into an enclosure for a Raspberry Pi video storage device.

Step one of this conversion was, as you might expect, removing all the original hardware from the cassette recorder case. From there, [iot4c] fitted the Raspberry Pi, a USB hard drive, and a YDS-5A DC-DC converter to power them. Depending on what the drive setup looks like, it might also make sense to add a USB powered hub. A length of Ethernet cable was left hanging out the back of the Atari XC12 so it could be plugged into the network, but a panel mount RJ45 connector could spruce things up a bit.

Of course, gutting an old piece of hardware and sticking a Pi into it isn’t exactly breaking any new ground at this point. But we did appreciate that [iot4c] went the extra mile to wire it up so the “Save” LED now doubles as a network activity indicator. Which pretty much brings it full circle in terms of functionality for a network-attached video recorder.

Earlier in the year [iot4c] converted a 65XE into a USB keyboard with the help of an Arduino Leonardo, but the vintage Atari aficionados will be happy to note that at least in that case the donor machine remained fully functional.

Commodore 1530 Datasette Gets A Digital Counter

Ah, the humble Commodore 1530 Datasette drive. It never enjoyed much popularity in the USA, but it was the standard for quite some time in Europe. [DerSchatten13] still uses and loves his 1530. When a co-worker showed him some 7-segment bubble LEDs, he knew what he had to do. Thus the 1530 digital counter (translated) was born.

[DerSchatten13] started out by building his design on a breadboard. He used every I/O pin on an ATtiny2313 to implement his circuit. Tape motion is detected by a home-made rotary encoder connected to the original mechanical counter’s belt drive. To keep the pin count down, [DerSchatten13] multiplexed the LEDs on the display.

Now came the hard part, tearing into the 1530 and removing the mechanical counter. [DerSchatten13] glued in some standoffs to hold the new PCB. After rebuilding the circuit on a piece of perfboard, he installed the new parts. The final result looks great on the inside. From the outside, one would be hard pressed to tell the digital counter wasn’t original equipment.

Operation of the digital counter is identical to the analog unit – with one exception. The clear button now serves double duty. Pressing and holding it saves the current count. Save mode is indicated by turning on the decimal point. If the user rewinds the tape, the counter will stop the motor when the saved count is reached. Cueing up that saved program just got a heck of a lot easier!

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