In this week we worked on PCB fabrication and milling. First of all we learn about the machine used of drilling PCB we use the SRM 20 machine for PCB production. Also we learn about the machine that how it work and what are the safety precaution for the machine First of all we need to characterize the design rules for PCB and understand the process of PCB fabrication. We have taken bit characterization file from lecture site and processed it. SRM 20 work on rml file. Mods is used to process the PNG file and produce the required rml file for SRM 20.
Before moving toward the Pcb Designing we first download the png of test pin
we also download the interior for the test pin
file of interior
Following are the Steps for PCB fabrication:
Step 1 : Open the Mods
opening the fab mods
Step 2: Select the Program
Selecting the program.
Step 3: After that Select "SRM 20" and "PCB png"
Selecting the machine.
Step 4: Outlook of Mods for SRM 20 PCB
Outlook for Srm 20
Step 5: Import PNG file from PC.
Click on "Select PNG file" and browse to png. Select and open it. Select the outline/trace. 1/32 for outline and 1/64 for the trace. Then click Calculate. Rml File will be automatically saved in your PC.
Importing the png file and saving the file.
Step 6: CLICK ON VIEW TO SEE THE MACHINE PATH
outline.
Step 7: Repeat step 5 for outline
Repeating the process for outline.
Step 8: Click on view to see the machine path
machine path for the boundary.
Step 9: Open Machine software"V Panel for SRM 20"
Set the start point manually. Save the X, Y and Z points. Click the cut and browse the rml file which we calculated using
mods and then click "output".
Note: Always cut the trace first with 1/64 bit.
Setting axis for the machine.
Step 10: Change the tool(1/32 for outline)
After trace, change the tool and place the 1/32 bit. Adjust the Z axis again and click "cut".
changing the tool.
Step 11: The circuit is ready.
Take it out and clean it.
Final pic of the circuit.
INDIVIDUAL Assignment: make an in-circuit programmer by milling and stuffing the PCB,test it
In this week we need to make the pcb of ISP, program and to test it. So I took Neil's circuit of AT tinny 44 from here. I took png file of trace and outlined and processed it using MODS to get the rml file. Gathered the components used it this circuit and soldered it. I tested circuit with multi-meter. Finally I programmed it using Linux operating system.
Step 1: Repeating the same procedure as above in group assignment open the modes and select the program .
Step 2: Generate the rml file for traces.
Step 3: Generate the rml file for outline.
Use same process for outline. Select 1/32 bit size.
Step 4: Open the V panel for SRM 20 software
Set the X, Y and Z position of the machine where you want to start the cut.we need to be more attentive while selecting the axis specially the z axis wrong selection can lead to demage . Then import the rml file generated through mods. First take the traces file and mill. After trace is complete, change the bit to 1/32 bit. Set the Z axis and then mill.
Step 5: Take it out and clean the pcb .
Picture of circuit after milling.
Step 6: Collect all the components for the circuit
Best practice is to write all the components with values and put double sided tape on side of paper. Paste the component against each name and also put board there.
Picture show the POM of the circuit
Step 7: Soldering
Open image and circuit board on PC and start soldering. My instructor told mye that Best practice is to solder the IC first then small components from center to outside direction.
Soldering the components on board.
After soldering the Final image is as under
The final image of the circuit.
Step 8: Programming
Before the start of programming, check all the connection using Multi-meter. Make sure that there is no any short circuit. Following are steps:
- To program the Fab ISP, you first need to install the necessary software for your operating system and download the firmware.
- Edit the Makefile
- Set the fuses / program the board
- Verify that the board is working properly
- Then you need to open up the jumpers to make it a programmer.
Ubuntu Software Install
Follow this tutorial and Install necessary Softwares, downloaded the firmware and edit the make file
For coding I connect my isp with my instructor isp and computer
After that Run the command "NANO MAKEILe","MAke Clean" ,"MAke Hex","Make Fuse " and "MAke Program"
GIF Showing commands
After Succesfully Programming and removing Zero Ohm resistor fabISP is ready for use
Picture showing the ISP is connected.