Recently I got on the idea that the Lua print command in Nspire Lua might print to the serial console. To test this, I built a max232 TTL converter and hooked my nspire to my laptop. And yes, it printed to the serial console!
Then I ordered an Arduino Uno, with the idea to hook it up to my nspire and control stuff.
A few days ago I received it and I started working. I had some problems until today because the the voltage on serial port of the arduino was to high for my nspire, and caused a reset everytime I connected it. Today I discovered (with the help of Kerm and benryves) that its only does that when its getting its power through usb, and not the power connector. So I switched to another power supply and all was fine
The print command in Nspire has some limitations though, you can only send bytes with data 1 to 127, and its also not the only data that gets send to the serial port. To overcome these problems, I made a little simple protocol to talk with my arduino. A sample data packet (in ascii) looks like this:
nomOKOCEHONOKOFOOOO@BDFON\r\n"nom" defines the start of a data packets, and "\r\n" the end (it gets automatic added with print). 2 chars represent one byte that has been split in two (to be able to send 0-255).
My first real world example is controlling a little led display through my nspire. The arduino here just acts as a "proxy" to send the data to the display.
Sadly though I can send data (yet) from the arduino to my nspire, but if I do some work on reverse engineering the other dock connector pins, I think I'll be able to find a solution.
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