Here is a picture of how everything will be connected

The Zipit Z2 is a tiny clam shell computer.  It was originally designed to be an messenger device for tweens.  it is easy to reflash the internal memory with openWRT.  I have been using a distribution which was put together and compiled by slug_ on a #zipit irc channel.  The distribution was downloaded from here http://blog.engine12.com/?p=340  

after installing configuring openWRT, I installed i2c_tools so that I can operate the environmental sensors.

The Zipit will be used for the following purposes;

• Controlling the i2c sensors
• An HTML server will provide web page control of the interferometer system
• Communicate with the HP 5508A measurement display
• Provide a means to calibrate the sensors
• Datalog sensor data and GPIB communication data.

I made a breakout board for the docking connector of the Zipit Z2.  The docking connector is 50 pin connector with impossibly small 0.5 mm wide connections separated by the same distance.  I brought each of the connections out to 0.1 inch pins.  From these connections I wired four conductor cables to the i2c sensors and the USB hub.

I am easily able to communicate with the HP 5508A by using a Prologix USB to GPIB adapter.  The adapter uses a FTDI USB to serial chip which is automatically recognized by openWRT.  a file //dev/ttyUSB0 is automatically created.  I then simply echo and cat with the //dev/ttyUSB0 sending plain text GPIB commands and plain text responses.

The i2c sensors include three MCP9804 temperature sensors which will be used to measure the temperature of the object being measured.  A fourth MCP9804 will measure the air temperature, while a AN2317 humidity sensor will be used along with a MPL3115 barometer will be used to measure the speed of light.