• These are the instructions to convert your version 1.4 kit (in bamboo case) to a kit in an acrylic case with I/O expansion board, including VT100 emulator.

    I would strongly suggest comparing the parts you received with the list below. Let me know if you’re missing anything and I will send a replacement.

These instructions are specifically to convert a version 1.4 main circuit board to use the I/O expansion. Instructions for construction the I/O expansion and acrylic case are in the booklet included with your kit, or can be downloaded here.

Parts List

*Updated for new USB keyboard version

  • 1 x Circuit Board
  • 1 x 16 pin DIP socket
  • 1 x 28 pin DIP socket
  • 1 x VGA connector
  • 1 x DB9 connector
  • 1 x 3.5mm audio jack
  • 1 x Micro SD module
  • 1 x DC power jack
  • 1 x USB-A connector
  • 4 x Rubber feet
  • 1 x MAX3232 IC
  • 1 x PIC32 IC
  • 2 x 4.7kΩ resistors
  • 1 x 220Ω resistor
  • 1 x 150Ω resistor
  • 1 x 100kΩ resistor
  • 1 x 82Ω resistor
  • 1 x 470Ω resistor
  • 2 x 27pF capacitors
  • 7 x 100nF capacitors
  • 3 x 10uF capacitors
  • 1 x 5mm LED
  • 1 x 8Mhz crystal
  • 1 x MCP-1700 regulator
  • 1 x Dual Pin Header
  • 1 x Single Pin Header
  • 8 x Jumpers
  • 8 x 8mm M-F standoffs
  • 8 x Nylon nuts
  • 4 x 6mm bolts
  • 11 x 14mm steel bolts
  • 11 x Square steel nuts
  • 19 x 10mm steel bolts
  • 19 x Hex steel nuts
  • 1 x 14 pin IDC cable
  • Laser-cut rear panel
  • 5 x Gray acrylic pieces
  • 7 x Blue acrylic pieces
  • If you received a micro SD card module with unattached header pins, you will need to solder them with the header pins coming out of the top of the module.
  • This may seem to be the non-intuitive location for the header, but it is correct for this kit.
  • You will need to desolder (or cut) the wires connecting to the power input (on the left side of the circuit board) and the audio output (on the right side.)
  • Remove the cables that are connecting the RS232 module to the circuit board. You will also need to desolder the Micro SD card module and Bluetooth module.

    If you want to keep the Bluetooth serial module, see the instructions below.

  • Add a 12 pin dual male header to the expansion connector on the lower right side of the circuit board.
  • You will need to use a razor or x-acto knife to cut the indicated trace on the main circuit board. Use a continuity tester to verify the trace has been disabled.
  • Add a wire to connect the “Ring/Tip” audio connector to the via located in the lower part of the trace you just cut.
  • You’ll notice the ribbon cable has 14 pins, while the connector on the main circuit board has 12 pins. The right-most pins provide power. These pins need to be connected to the “+Vin/GND” connectors on the left side.

    There are two ways you can do this. You can cut the right-most two wires (carefully!) on the ribbon cable, and connect those to the “+Vin/GND” connector (the inside wire is GND, the outside wire is +V.)

  • Another way is to use a two-pin male header, bend the ends to insert into the right side of the ribbon connector, and solder a wire to the pins that connect to the “+Vin/GND” connector.

    The power connectors on the ribbon cable are in the same orientation as the power connectors on the left side of the board, with +Vin on the top, and GND on the bottom.

  • Run the wire along the bottom of the board to the ribbon cable connector.
  • Connect the I/O expansion board to the main circuit board and test it.

    If everything works, you can assemble the acrylic case, and you’re ready to put it all together.

Depending on the age of your Arduino, you will probably want to update the software. You can find the instructions at this link.

You should install the latest disk images and settings profiles to your SD card.  You can download those here.

Once you have everything buttoned up, you will no doubt want to try out the VT100 emulators with your Altair-Duino.  Click here to see instructions and a video.

If you’re looking for a PS2 keyboard and/or a VGA monitor to use with your newly upgraded Altair-duino, I can recommend these from Amazon. They’re inexpensive and they work fine for retro-computing:

  • UPDATE: version 1.1 of the I/O expansion board (available March 2020 and later) now has a USB keyboard connector.  Any standard wired USB keyboard should work, but you need to avoid using a keyboard with a USB hub.   Some keyboards have built-in USB hubs and those will not work either. If your keyboard has one or more USB sockets on it (to connect a mouse for example), or is wireless, then it likely contains a USB hub and will not work.

    The build of the new I/O board will be slightly different – there are now only two 4.7k resistors (instead of four) and the relocation of the USB connector.

  • I also like this LSLYA 8 inch TFT LCD Security Monitor. It’s small, light, and inexpensive (about $64) and it has a variety of inputs, including VGA, HDMI, composite, and component. Everything you need for almost all retro computing possibilities. Plus it has a 4:3 retro computing aspect ratio.

But I don't want to lose my Bluetooth!
You can keep your Blutooth module, but it will require you to flex your DIY muscles!

This procedure is completely optional and is only required if you want Bluetooth and the VT100 emulator.

  • You will need to disconnect the RX and TX pins from the main circuit board. It may be easier to completely desolder and remove the modules, clip (or desolder) the RX and TX pins, then resolder the Bluetooth module.

    You can then connect the RX and TX pins directly to the Arduino.

  • (These instructions are directly from David Hansel’s documentation.)

    This port is disabled by default since it uses two I/O pins that are not connected to headers on the Arduino Due: the pins controlling the RX and TX LEDs next to the Native USB port (framed in red in the image on the right). These pins are accessible as digital pins 72 (RX) and 73 (TX) on the Arduino Due. Despite their location next to the Native USB port they have no connection to the port and can be freely controlled by software. To add a serial interface using these pins do the following:

    (Optional but recommended): remove the RX/TX LEDs. I did try leaving the LEDs in place and just soldered onto the LEDs themselves and serial communication did work. However, the LEDs go to +3.3V through a 1k resistor which could possibly interfere with the serial signals. Your mileage may vary.

    Solder wires to the pads on the left side of the LEDs (the side closer to the “RX” and “TX” labels). These will be the RX and TX wires for the serial connection.

    In file host_due.h, change

    #define USE_SERIAL_ON_RXLTXL 0


    #define USE_SERIAL_ON_RXLTXL 1

    and upload the sketch to the Arduino.

    Connect the RX LED to the TX pin on the Bluetooth module, and TX LED to the RX pin.