For this week I made the Hello.Serial.Bus. This boards use the Tiny45 microprocessor.
http://academy.cba.mit.edu/classes/networking_communications/index.html

I followed this tutorial: http://www.as220.org/fabacademy/tutorials/networking_serial_bus.php

I made 3 boards. 1 bridge and 2 nodes. You need at least 2 nodes to make this work. The bridge counts as a node.

As you can see, the only difference between the Bridge Board and the Node board is that the Bridge has an FTDI.

After you have the boards milled, you have to program them, making sure you name each board with a different ID.
This you have to do it editing the C code.

You can download all is needed to program your board here:
http://www.as220.org/fabacademy/tutorials/Downloads/bus_fixed.zip

I used my FabISP to program each board with different IDs. 0,1 and 2.
One thing you have to keep in mind is that every time you program the next board you have to change the ID found in the hello.bus.45 file you have downloaded.

Don't make copies of it, just edit it and overwrite it. Look for the following line in the C file:

#define node_id '0'

I named the boad as ID 0 , the first node as 1 and the second node as 2.

After doing that, you have to program it using the FabISP. To do this you will need to power the boards through FTDI. You will have no problem with the Bridge, but with the Nodes you will have to power them through the Bridge board every time you program them. Always through the FabISP.

I program them using Terminal. You have to use this command:

sudo make -f hello.bus.45.make program-usbtiny

If you are successful programming the boards you have to see something like this:

Follow this steps to see the boards talk:

1. Plug your bridge into your computer (with the nodes attaches).

2. Connect the nodes with a cable as shown in the picture.

3. Open a Arduino IDE

4. Open the serial monitor from the "Tools" menu > serial monitor

5. Make sure the baud rate is set to 9600.

6. Enter number of a note (pick a number) into serial monitor - press the <enter> key or the "send" button on the serial monitor.

7. The LEDs on all the boards should light up once.

8. After all the boards light up, the board with the number you entered into the serial monitor should light up again.

9. The node name (ex: node 1) should also be displayed on the serial monitor.