5. Electronics production

The goal of this week is to make an in-circuit programmer by milling the PCB, and to program it.

PCB preparation

For this week, I choose to made the FabTinyISP of Brian.

After reading the documentation closely. I decide, to prepare a list of all the electronics stuffs and keep it in side.

Electronics stuff

1x ATtiny45
2x 1kΩ resistors
2x 499Ω resistors
2x 49Ω resistors
2x 3.3v zener diodes
1x red LED
1x green LED
1x 100nF capacitor
1x 2x3 pin header

Files machine preparation

I download the traces and the outline cutout to process them in mods.

Note

In our fablab, we have a Roland machine, we get caracterize it just there.

Init

Right click
programs > open server program > machines > Roland > mill > SRM-20 > PCB
Near the Roland SRM-20 milling machine module, right click
modules > open server module > file > save

This module will help you to save the calculate file on your personal machine.

Configure

We don't have our machines in the network, so we need to configure only two modules (mill raster 2D and Roland SRM-20 milling machine) for calculating and downloading the files for the machine.

init_mods_5

`Roland SRM-20 milling machine` module configuration

This module will have the same configuration for the two modes.

speed: 4 mm/s
origin:
- X: 0 mm
- Y: 0 mm
- Z: 0 mm
jog height:
- Z: 2 mm
home:
- X: 0 mm
- Y: 0 mm
- Z: 10 mm

`mill raster 2D` module configuration for traces

tool diameter: 0.3 mm
cut depth: 0.03 mm
max depth: 0.03 mm
offset number: 7

`mill raster 2D` module configuration for outlines

tool diameter: 1.5 mm
cut depth: 0.4 mm
max depth: 1.4 mm
offset number: 7

Milling PCB

Roland SRM-20 milling machine

Software

I used the V-Panel software, he's integrated in the machine.

vpanel

Traces

I used the [1/8″ 30 degree engraving bit] end mil for the traces.

traces

Outlines

I used the [1/8″ 30 degree engraving bit] end mil for the traces.

pcb_finished

PCB fabrication

Preparation

I took my box where I put all my preparation, and start to setup the soldering gun for 380°. I put my laptop near me to get easly the schematics, get on the leds and the air aspirator.

Soldering

Soldering flow

I start to solder one by one each elements:

attiny45
1kΩ resistors
499Ω resistors
49Ω resistors
3.3v zener diodes
100nF capacitor
LEDs
2x3 pin header

fab_isp_finished

Testing

Using the multimeter
Connect it in usb port to see if the led work

Some mistakes

The soldering gun was too hot, so my solder was not so shinny
I invert the place of LEDs
Solder the wrong resistance in the wrong place

Program the FabIsp

Now it's time to program the board to transform it to ISP 😄

Connect the AvrISP

AvrISP is not well connected

The led is orange 🍊

AvrISP well connected

The led is green 🍏

Prepare the downloaded program for the build

I switch my laptop in ubuntu (I have dual boot, and I already have all stuff to develop in ubuntu), and I download the firmware and I extract it in my documents.

Launch the commands

Open Makefile with vsCode update variable PROGRAMMER to avrisp2
Run sudo make flash
Run sudo make fuses
Test the usb functionnality
Run sudo make rstdisbl
Removing the bridge on the solder jumper
Test programmer