week4 : electronics production

Assignments

Make your own FabISP.

Milling PCB

We need to control a milling machine really carefully, otherwise it will destroy itself. We confirm the milling board is totally flat and clean first, then we need to put a sacrificial layer to mill and cut out a PCB board. It should be PCB, and be flat. Then, to confirm the milling needle can shave perfectly, first we should use outline data. Call "fab" in Linux and launch the FabModule that can controll the milling machine. Load the data and press make path button. Then measure the left bottom point from the original point. Go back to the milling machine, turn on it and make sure the needle is corret, then press "down button" and let the needle touch to the PCB then push "up button" little bit. So it can shave only the surface. Go back to the FabModule, the depth should be 0 but it depends on the condition.

Press "Send the path" and the milling machine will shave the outline. If it success to shave correctly, then you can send the inside data. After that, send the outline data again and change the depth and the needle to 1/32 one.

Soldering

Before soldering, I pick the all of stuff. Actually it's not first time to solerding the stuff but I haven't done with such tiny parts. And the technics were different. I listed up these.

  • Soldering from inside to outside, bottom to top and big one to small one. Otherwise it will be hard to soldering.
  • Put the solder little bit first, then put the stuff on it and put the soldering iron. The solder will melt and attach the stuff.
  • About soldering with tiny resistances, put the solder only one side first, then put the resistance, melt the solder and attach it. Then put the solder on the other side and melt it. Because of its size, it's so hard to put it correct position.

Installing software

Just follow this page. http://academy.cba.mit.edu/content/tutorials/akf/programming_FabISP.html

My laptop is the MAC OSX, so I need to install the CrossPack. Then I did some commands. Here is the result.

The under picture, you can find that my laptop found the FabISP as the USB module.

Fixing

After finishing all things, I noticed that I put wrong resistors in my FabISP. I don't know why but even it worked well. But I don't want to account any troubles during programming in a future, so I fixed it.

As shown above, first I put a 4.99 ohm resistor and two 10 ohm resistors and installed the FabISP. However, it was totally wrong. So I put correct resistors and it still works well.