How to Make Almost* Anything | MAS.863

Ella Peinovich | M.Arch Level III, MIT

[06_Micro Controllers]

Blinking LED Micro Controller

As seen above, the FabISP Programmer is linked to the computer via a USB cable and is then ganged to the Micro Controller using a 6-pin wire connector. Once programmed, I hit the button and the light turns on!

As simple as this function is, there were many steps before getting to that point: including designing and programming the micro controller, as well as fabricating the custom board. The steps are described in more detail below, along with the many lessons I learned along the way.

Step 01 | Design

I modified the microcontroller layout to include the LED and BUTTON seen on the right of the schematic. I also took extensive notes of the design process, linked here: Eagle Make. It was extremely easy using Eagle and by flipping between the artwork and schematic I has able to learn a lot about how the power source and ground effected the flow of the current. Each component size is still a bit of a mystery to me, but I really felt I made bounds in the right direction.

Step 02 | Milling and Stuffing

I learned a few new lessons this time through the milling process which did not come up last time while making the FabISP. 01 | The traces circles in red on the PNG were too close when milling so the when I generated the tool path the area between the pads for the center component and the traces that ran under it were connected. To avoid this in the future, it was recommended that we reduce the milled traces from the default of .016 to .012 or stretch out the board to create more room. I had to go in and use an exacto blade to carve out the unwanted connections. 02 | When I went to stuff the board the tip I had on the soldering unit was too big and looks to have been damaged, it was flattened on two sides and thus was really difficult to maneuver around the components. 03 | Most of my solders were gobbed up and milky in color; I understand that our lab is still needing to acquire some flux, which would help this problem. Where is our flux?

Step 03 | Programming

After hearing many analogies of overflowing water buckets and cooking during class I felt clueless (along with many others) walking into our programming tutorial. It took 3 hours at the end of which I can fairly say I understood the logic of the code, which resembled some scripting that I have done in the past. However, I felt really unsatisfied to find that the windows operating system could not run the Make file, all PC users were getting the same error message. "This application has requested the Runtime to terminate it in an unusual way." So I found a friendly Mac user...

...Huang kindly let me program my micro controller using his computer and... it worked! What a miracle.