electronics design

Echo hello world

I first started with making the board in Eagle software. After including Fab.lib, I added components and used net,label, and command codes to create a schematic. When the ERC was satisfied I continued with making the board. Here I imported Fab.dru file to make the design compatible with milling machines. Changing the grid spacing was helpful when I had to route paths underneath a component, in this case ATTINY chip. I added the outer layer using GIMP by first cropping the board, adding borders and finally flattening the image.

Milling the board was the next step. After initial struggle with connecting to the machine, It was fairly straightforward to get the board working. I moved on to the favorite part of the work, soldering, and used the similar soldering principle as the previous board. The crystal was more challenging to solder than the rest of the board.

Next I moved on to programming the board using the USBtiny programmer. I had to make the usb soldering thicker to get the reliable connection. I make and downloaded the c program using 'avrdude'

Finally I went to test the echo program. In this step I used both python and mods, but run into problems in both situation. The issue was mainly the port could not open between serial usb and the program. I was using Unix emulator on the windows machine. I had to install some packages necessary for mods, including npm, but it didn't help

I finally switch to Python on a Mac computer to test the board. The board responded reliably this time, echoing the keyboard input. I used term.py under python 2.7 environment. Python 3.5 is incompatible with the code