[WEEK04] Erectronics Production

What I made

I made cicuit board with milling machine and manual soldering.

1. PCB fabrication

I made PCB boards for FabISP with milling machine and fiber laser cutter.
FabISP is a programmer for AVR microcontrollers designed by various makers. So I tried to make them of different versions on each machine.

Milling machine hello.ISP.44
Fiber Laser cutter hello.ISP.44.res

1.1 Milling Machine

The machine that I used was Roland MDX-40.

At first, I shaped the surface of a follow board to level the platform. And then, I set the PCB material "FR1" upon it.

I used the following endmills.

I created NC code file with Fab Module.

input format file name output format process
image(.png) hello.ISP.44.traces.png Roland mill(.rml) PCB traces(1/64)
image(.png) hello.ISP.44.interior.png Roland mill(.rml) PCB outline(1/32)

The origin and the number of rotation ware set on Roland Vpanel for MDX-40.

I milled the trace. And then I cutout the outline after changing the mills .


hello.ISP.44.trace.rml: Download the file
hello.ISP.44.interior.rml: Download the file

1.2 Fiber Laser Cutter

I tried to make PCB board of another design with another way.The laser cutter I used was trotec speedy 100 flexx. This model can switch between CO2 lazer and fiber laser. So I milled the trace with fiber lazer mode and cutout the outline with CO2 lazer mode.
At first, I modeled 2D data for lazercutting based on "hello.ISP.44.res.traces.png" with Illustrator.
The settings was as below.

I set the resolution of the raster data for 600dpi and engraved the board. But, some areas were short-circuit. So I changed it to 1000dpi and retried. The next one was successful.

I checked wheather there was any short circuit and any lines were connected using digital multimeter.


hello.ISP.44.res.traces.ai: Download the file

2. Assembly

I soldered the following components to the PCB board using a soldering iron. It was the first time soldering surface mount parts. So I desoldered with desolder brade many times. Though the circuit had been completed, the soldered part was not shine and smooth. I need to practice more.

Parts list
Part name Quantity
ATTiny 44 microcontroller 1
Capacitor 1uF 1
Capacitor 10 pF 2
Resistor 100 ohm 2
1 Resistor 499 ohm 1
Resistor 1K ohm 1
Resistor 10K 1
6 pin header 1
mini USB connector 1
0 ohm resistors 2
Cystal 20MHz 1
Zener Diode 3.3 V 2

3. Programming

I tried to program to the circuit above to make it FabISP. I used Mac on this process.
At first, I Downloaded and Installed the following software.

And then, I downloaded "FabISP Firmware for MacOS 10.8.2", and performed the following operation.
Open terminal navigate to the desktop:
    cd ~/Desktop/
Unzip the firmware.zip directory on my desktop.
    unzip fabISP_mac.0.8.2_firmware.zip
I plugged the mini USB connector for the FabISP into my computer and the AVRISPmk2 into the 6-pin programming header. And I made sure that the green light was lighten.

Then I programmed the board in accordance with the instruction.
    cd Desktop/fabISP_mac.0.8.2_firmware
    make clean

    make hex

    make fuse

    make program

It seemed to be successful.
So I checked the System Profiler and verifed my FabISP was working correctly.

At last, I removed two 0ohm resisters to use this board as a programmer.

4. Additional challenge

I tried to program another board using my FabISP.


I assemled the board made with a fiber laser cutter (20MHz resonator version)

Edit Makefile

I editted the makefile because I was going to use FabISP as a programmer.
- Remove the "#" in front of the line with "usbtiny" in it
- Add a "#" to beginning the line with the "avrisp2" in it to comment it out.


I connect my FabISP to the 6-pin programming header on the board.Each board connect to my computer with mini USB cable.

I programmed it in the same way as the previous. The same message displayed, so I thought it was sucessful. But "FabISP" wasn't listed in the system profiler. The computer doesn't recognize it as a FabISP or even any other devices.


At first, I checked that there was no short circuit with digital multimeter. There seemed to be no problem.
And I tried to program the board using AVRISP. When I connected them to the computer, the yellow light was lighten.

So I think there is a defect somewhere. Certainly, many solder joints doesn't look shiny and smooth.But I still can't identify where the problem is. It is a remaining task.