assignment: Internet O with IR.

     details: Initially I had a lot of trouble figuring out just what was
     happening in the unmodified i0 boards. After speaking with Manu and 
     Shani I figure I sorta got a handle on it. I chose to modify the board
     to tranmit IR as I thought it might be useful to my project. In addition 
     to adding an IR LED and IR phototransister I needed to modify the power
     source on the board. 

     Powering the board with a 9 V was fairly simple, as was adding a photo
     LED in place of the nmosfet. Initially I used a visible LED allow me
     to verify functionality. For reception I replaced the diode with an LED

     Once the board was powered I modified to code to get everything working.
     For the output LED i needed to change to initialization settings as 
     well as the putclick subroutine. I slowed the click_delay down so as
     to allow me to verify visually that the device was outputting correct
     binary. I then replaced the visible LED with an IR LED. Getting the
     chip to recieve proved difficult and as yet I have not finished that 
     part, though I have confirmed that the A/D comparator dealie is in 
     fact responisve to changes in line voltage. Pictures and files below.


     After tearing down and rebuilding the boards component by component
     I discovered that the IR LED is marked at the anode and not the cathode
     end as was the case with the Red LED. As a consequence I had installed
     it backwards. Reversing the IR LED I was able to transmit clicks but
     only at a distance of roughly 2 inches. I checked the range of the 
     IR transister using a standard remote control and could detect clicks
     at a range of several feet reliably, leaving me to conclude that the
     limiting mechanism is the IR LED. I increased the output by replacing
     the 449 Ohm resister with a 100 Ohm resister and while the range improved
     a bit it was still on the order of inches as opposed to feet.

     -> .cmp of i0 circuit

     -> .brd of i0 circuit

     -> .sch of i0 circuit

     -> .cmp of i0 to serial circuit

     -> .brd of i0 to serial circuit

     -> .sch of i0 to serial circuit

     -> .asm of i0 circuit 

     -> .asm of i0 to serial circuit