Source: Pexels

6 / 3 / 2019

WEEK 4: This week, we had to make our circuit boards which include soldering, and possibly also programming.

To locate the kind of and assemble the components, I followed the guide on: http://fab.cba.mit.edu/classes/863.16/doc/projects/ftsmin/index.html#toolchain, all relevant information can be found on the site.

To begin soldering, first, clean the circuit board to remove any oxidation that might have occurred in the air the time between milling and assembling. Then I located all the parts needed around my working area so it was clear to see. I began with the resistors, moving on to larger parts and left the chip as the last to solder on, due to its larger height that might hinder my way of work if done before others.

Parts and board

For the actual process, I began with heating up the small-tipped soldering iron. To check when it’s ready, lightly tap the iron tip onto a moist sponge, a sizzling sound should be heard. Next, hold the iron tip on to the joint on the board for a couple of seconds to heat up, then hold the solder up close and melt it until a small amount has flowed onto the joint. Then, get the part required and, using a pair tweezers, position it so that the leg of the part touches the solder put on earlier. Feed more solder in using the soldering iron until the joint combines and forms. Remove the iron and let it cool. I repeat these steps to assemble all other parts.

To check if the soldering was done correctly, I used a multimeter to test the connection by measuring the current going through. To do so, I hold the anode and cathode ends of the multimeter to the joint made by soldering and another end of the circuit. If the multimeter beeps, indicating a resistance/current is measured, the connection was done successfully.

Completed Board

After the circuit board is completed, I went on and tried to program the ISP programmer. I followed the guide on “Building the FabTinyISP” as linked above. Before plugging into the computer, I had to connect the bridge on the circuit board so a complete circuit is made. I followed the steps including modifying the MakeFile, opening the terminal and run different commands including ‘Make Flash’, ‘Make Fuses’ and so on. My programmer didn’t work several times encountering issues like connectivity – which I’ve fixed by adding more solder and tape on the back to secure the connection. For a few times, I have gotten to the last stage up till blowing the reset fuse. And when I tried from the top again, it failed as it reached the ‘make fuses’ command. At the moment I’m still not sure what the problem is, but I will try to make another one during next week to program it successfully.

To conclude, I found the soldering process quite fun to learn and pick up, and it will definitely come in handy in the future. I’m still a novice in soldering, therefore I’ll try to improve my skills to clean up my joints and accuracy over time. As for programming, I found it quite finicky to understand and learn for now, and it’s difficult to find the roots of different problems and try to fix what went wrong. It will definitely take more time to explore the scope of this area.

 

UPDATE

7 / 3 / 2019

I’ve gone back to the Fab Lab and retried programming my programmer by identifying what the problem would most likely be. With the help of my tutor, we used a multimeter to test if all the joints are connected properly. We discovered a possible short between two ends of the chip – and proceeded to remove the solder on these two joints and re-solder them separately to ensure the connection is fine.

Moreover, I’ve tested using a different computer, different USB connectors, a different program, and different ribbon cables. They’ve also resulted in the same outcome I’ve had before, which is the programmer stops at the stage “make fuses”.
 

In the end, I was suggested that the best way is to remake another programmer since we couldn’t find any more possible faults on my original one. For now, I’ll focus on next week’s project and mill my own circuit board and will go back to this later on and try to make a functional programmer.