This week’s assignment was to make the FabISP, a PCB, wich we will use during the Academy to program other microcontroller. Starting by dowload the PNG file that has been used to mill the circuit board froma a copper plate. The milling machine is a ROLAND SRM-20

• Table size (LxP): 232.2 x 156.6 mm
• Distance from collet tip to table: 232.2 x 156.6 mm

The machine will use a a tip of 1/64 size to mill from the traces , once the traces will be done it will need a tip of 1/32 in order to cut the board.T

to generate the file I used the Fabmodules

In our lab we are using the Roland MonoFab SRM20 so we need a rml file

Machine settings

• Open fabmodules.org
• Click on Input Format
• Choose Image (.png) and Upload Image
• Click on Output Format and choose the machine (Roland Mill (.rml))
• Setting machine: machine SRM-20; Xmin 0; Ymin 0
• Click on Process and choose (PCB traces(1/64)) or (PCB outline(1/32))
• Change offset to 5 (this is a personal setting)
• Click on Calculate
• Save

Milling the board

I secured the board in the milling machine with double sided tape to keep the model from moving in the milling machine

Machine settings

• Turn on the machine for the heating, at least for 20 minutes
• open Roland Vpanel. Load the .rml file
• Set the X,Y,Z axes

SMD Soldering

This was the hardest part of the assignement, soliderind so tiny components on traces kept a lot of time. Some traces was damaged by the heater so i had to repair them by adding some littel copper wire

Board programming

In order to program the board I used a USBasp - USB programmer for Atmel AVR controllers

Download the firmware from the Fab Academy : wget http://academy.cba.mit.edu/classes/embedded_programming/firmware.zip

and unzip it