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5. Electronics production

Tasks for this week:

  • Characterize the design rules for your PCB production process (Group task)
  • Show how you made and programmed the board
  • Explain any problems and how you fixed them
  • Included a ‘hero shot’ of your board

Group task

During group task we have learned the process of production electronic board: - The rules to design it in PNG format. - The usage of the program that converts PNG file into the format understandable for CNC machine. - The soldering of the board. - The process of programming PCB.

The rules to design it in PNG format.

We have learned certain requirements for the tool that helps to convert monochrome PNG file into G-code. The main requirement is that there should either black or white parts of on the picture. The white parts are about to stay, and the black parts are about to be cut out by the mill. Therefore, it is important to keet the distance between significant enough so that the endmill can go between two white parts. For example, if the endmill is 0,4 diameter, the distance between white parts should be not less than 0,5 mm.

The usage of the program that converts PNG file into the format understandable for CNC machine.

We have learned the usage of http://fabmodules.org/ that help to convert the picture into G-code understandable for CNC machine. One of the most important things to pay attention is the visualization of the final G-code. It is useful to check if the endmill goes through in every narrow part between traces. Therefore, it is good to compare the initial picture of traces with the G-code.

The soldering of the board.

The most important lesson is that the adhesion of the solder cannot be good if the metal part of the component is cold. Therefore, it is crucial to the heat component, and the sitting place with the soldering tool simultaneously for several seconds and then apply the solder. The spread of solder around the part and trace is a sign of good adhesion.

There is more information about the group assignemt in my classmate’s page .

Individual task

On the first step, I created two files to cut out the board. I used files provided here http://fab.cba.mit.edu/classes/863.16/doc/projects/ftsmin/index.html

To convert PNG files to CNC milling format, I used http://fabmodules.org/

Then I prepared the CNC machine.

I set up zero points for all dimensions.

I have used two head mills. One to engrave need pattern.

And another one to cut the board.

I take the board out after the process was finished.

As the blank board had not free space. I changed it to the new one.

I had this result with my name in Chinese.

Then I soldered the board according to the following schema.

After I finished, I stick a piece of tape on the bottom of the board to improve the connection between the board and the computer.

Then I connected the programmer board to my board to start the process of programming.

As I use Windows, I need to install the following programs:

  • Atmel GNU Toolchain
  • GNU Make
  • avrdude
  • Drivers for a programmer from http://www.atmel.com/tools/atmelstudio.aspx

Another step was to download Firmware for my board. I took it from here http://fab.cba.mit.edu/classes/863.16/doc/projects/ftsmin/fts_firmware_bdm_v1.zip and saved it on my computer.

With GIT terminal I opened this folder and cleaned it to create a new hex file for my board.

Then I created a hex file.

On the next step I needed to upload hex file into the chip on my board, but I had a problem with connection. The reason and solution to this problem are in the next chapter.

After I solved the problem, I used a command “make flash” and uploaded firmware to my board. And run the make fuses command. It set up all of the fuses except the one that disables the reset pin.

I checked if the new board is recognized by my computer. It was ok.

Then I run “make rstdisbl” to disable all pins.

On the final step, I unsoldered the jumper and got my new board.

Problems

The only problem that I have got was the connection problem when I run the command make flash. The solution to this problem was to make a better connection for electronic parts while soldering.