Build Your Own Altair 8800 Personal Computer

The MITS Altair 8800 was the first commercially successful personal computer. Created by Ed Roberts in 1974, it was purchased by the thousands via mail order, proving there was a huge demand for computers outside universities and large corporations. Its influence was immense: For example, after seeing the Altair featured on the cover of the January 1975 issue of Popular Electronics, Bill Gates and Paul Allen founded Microsoft (then Micro-Soft) in order to write a Basic interpreter for the new machine.

The Altair sold for US $439 in kit form. Original machines are now collectors’ items that trade for thousands of dollars. Fortunately, there are some cheaper alternatives for people who want to get a direct understanding of the Altair computing experience. Modern kits that replicate the Altair hardware as faithfully as possible are available, as are purely virtual online simulators. Falling somewhere between a replica and a simulation is the $149 Altairduino kit from Chris Davis. The Altairduino duplicates the front panel of the Altair in all its LED- and switch-festooned glory while emulating the internal hardware (including some once fantastically expensive peripherals), using an Arduino Due.

The Altairduino is derived from David Hansel’s work on cloning the Altair with the Arduino Due and Arduino Mega 2560. If you want to build one of Hansel’s designs from scratch, you can do so by following his free instructions on hackster.io. The advantage of Davis’s kit is that it provides all the components, including a nice bamboo case and plastic front panel, along with a custom printed circuit board (PCB) that greatly simplifies construction.

The original Altair’s relatively large size means that most of the components are fairly well spaced out on the PCB. Even a beginner could do much of the soldering, although a little bit more experience is required for trickier areas, such as the headers that connect to the Due. The fiddliest bit is adding the LED indicator lights. These are mounted on spacers, and it’s best to put the front panel in place to ensure alignment, which can put you in one of those situations where you really wish you had an extra pair of hands to hold the panel, LED, and PCB tightly together while you solder. The online instructions are detailed and well illustrated, but I would recommend skipping forward and making sure you solder all the resistors in the kit before proceeding to add other, taller, components.

The Altairduino improves on the original Altair in two important respects. First, it offers modern interface options. You can connect an old-school terminal using an optional DB-9 connector (which I will stipulate should properly be called a DE-9 connector, so no need to send me letters this time!), but you can also use a soft terminal running on a computer via a USB connection, or even Bluetooth. [READ MORE]