CSE 477 Spring 2014

This is the project page for CSE 477 Spring 2014.

PCB update

21. May 2014 Zishen Hu Project Log (0)
I finalized the PCB schematic and layout. Some of components are custom libraries because I found the the physical circuit components  are too small to solder, I need to make the pads on the board bigger in oder to ease soldering process. The way I use to test if the physical circuit components fit the board is that I printed out a 1 by 1 scale board on regular printing paper, and then place the some components to check of accuracy of the custom libraries. This method allowed me to ensure the the size of the pads are right, and correctly spaced. More importantly, it saves our group not to place wrong order before it is too late.  I placed order at advanced circuit, one of the PCB manufacturers, hopefully the physical boards will ship no latter than week. The next goal is to solder all the components on the board and then perform thorough test for the circuit. 

PCB Status

7. May 2014 Zishen Hu Project Log (0)
In the past week, we were able to ordered most of the needed hardware, and I was able to use Eagle to start making custom PCB. Eagle has a lot of open source libraries for the hardware we ordered, yet I had to make my own libraries that I could not find online. For example, I made DC/DC buck converter TPS62730, and its footprint size is 1.5mm x 1.05mm, therefore even every little error could be critical.  I also made a library for KTIX9 accelerometer that is little bigger the DC buck converter. 
However, after talking with TA and Professor Patel, we decided not to use buck converter for two reason, the first one is it is not necessary to DC buck converter to make the system power efficient since the system will be operating with 3.3 V; the second reason the DC buck converter package is QFN, which in not human solderable. It is better off not to use. In conclusion, we will need finalize the both schematic and layout the PCB, and then launch 1x1 scale PCB on printing paper, and check if the parts we order fit into spots.