Saturday, February 22, 2014

The Briel Altair 8800 Replica Kit

I recently built a Briel Altair 8800 computer kit. Introduced in 1975, the original Altair 880 was one of the first computers that could be built by a hobbyist. Microsoft's first consumer product was a version of BASIC for the Altair.

Vince Briel has been selling a replica of the Altair 8800 for a few years. As the front panel requires some custom manufacturing, the kits are offered in batches. Late last year pre-orders were taken for the fourth batch of the kits, and I placed my order for a kit (he also sells fully assembled systems). I also ordered the optional RAM disk that emulates two floppy disk drives and allows the system to run the CP/M operating system.

I've made a series of YouTube videos documenting my experiences with the system:

While I tried some original Altair programs like BASIC, and toggled some programs in with the front panel switches, mostly I have been running the CP/M operating system. I used CP/M back in the 1980s on several platforms, including an Apple II with a CP/M card. The old dial-up Bulletin Board (BBS) Systems, predating the Internet, often used CP/M and gave users command line access to it.

I'm having fun running old CP/M programs like the Star Trek and Zork adventure games and WordStar word processor.

Fun With an Oscilloscope

I picked up a fun little toy this week, the SparkFun AVR Oscilloscope Clock. It displays an analog clock on an oscilloscope in X-Y mode. Here's an image of it driving my BK Precision oscilloscope:

It comes as a small pre-assembled board that just needs power and a connection to your 'scope.

It has a ton of different display options which can be controlled from small push buttons.

It packs a lot of features including optional connection to a GPS for time synchronization, control from a USB or serial port, and you can modify and reprogram it's firmware.

Here it is operating with my Heathkit IO-4205

An earlier version was sold as a kit, but unfortunately the latest design is only offered as an assembled product, due to the heavy use of surface mount components.

It can be a fun way to show off a spare oscilloscope you have lying around. It can even be useful as a piece of test equipment: it has a mode where it can act as a function generator and another where it can
operate as a serial port terminal.