This week we deal with circuits, fortunately for me during my physics highschool studies I was thought in ample detail the function of circuits and the theory, making it possible for me to undertstad the maths, function of components and theory behind this week. However I had never digitally designed a circuit.
During this lecture Neils went through a lot of details about circuits, their application and the function of the components, as well as some of the maths involved. It was hard to follow at time since it was pretty fast paced and quite techincal, I managed to understand almost everything but from what I gathered it seems that a lot of the information was surplus for this week focus.
The assignments for the first week were:
I.Redraw the echo hello-world board:
Add(at least) a button and LED (with current-limiting resistor) check the design rules, and make it.
Highlighted necessary tools:
>> Milling machine
[Eagle dowload link ]
The Lesson On Circuits by Emma:
The lecture Emma gave us on circuits this week was fantastic, I was impressed by how clearly she taught the potentially trick to explain subject of circuits.
She also guided us through the functionalties of Eagle, as well as showing us how to export files.
She also shared with us many important files and links which I will list below:
>> A powerpoint on using Eagle for Electronic Design
>> A powerpoint on exporting files from eagle to the Roland Modela
>> A tutorial website on using eagle
>> Many Youtube tutorials:
=> Tutorial 1: Eagle Schematic
=> Tutorial 2: Printed Circuit Board Layout
=> How to Use Autorouter With Net Classes
One of the most important files she shared with us was the library file for Eagle (click link to download)
Creating The Circuit On Eagle:
Fortunately the official guide to making the Echo Hello-World board was really clear and guided us, almost too smoothly, through the all process
I also downloaded the official Eagle library provided on the schedule by Neil, combined with the one from Emma I could access all the components I need to contruct my board. (Click link to download)
From there it was just a metter of following the instructions and tutorials to complete the assignment.
At first I came across some issues, by checking with DRC some errors came up, the lines wheren't more then 0.4mm apart (see image 1#) which is the mimum distance between lines imposed by the width (1/64) of the end-mill. I solved the issue by reducing the width of some lines (0.2mm, see image 2#).
From the completed design I decided that it looked far too similar to the one from the guide, so I deleted my design file and started from skratch, it connected the components using Autorouter, which was not easy, since achiving 100% connection (which means that all the connections have been made) is very tricky and depends heavily on how well you placed the components in the first place, which takes a LOT of trial and error. [It also takes a long time if you put effort to 'high' (which referes to how hard it tries to make a good route), because it tries out every possible route, similarlly to the travelling salesman problem *shout-out to all computer scientists*, it takes quite a while to solve].
Once that was done I was left with a good looking design file, I added 'Jack's Echo' and the extra rectangular layer for the fab-modules to recoginze the edges, and then exported the traces and cut-out as seprate png images, Monochrome, resolution: 1000, area: full. (as explained in the afromentioned,downloadable presentation). (see image 3#)
Milling & Soldering The Board:
Following the rules from week 4# I uploaded my png to the Roland Modela and produced my Echo board, everything went smoothly this time using the Modela.
(see image 4# for the settings I used)
This time I decided to try out a new soldering teqnique for the sake of experimentation:
I placed the solder every copper pad before the components themselves, then I placed the components ontop of the cold solder and used the heatgun to melt the solder once again and used a pair of tweezers to place to component in place... This worked suprsingly well, actually perfectlly, I had no shorts at all, I obtained a very clean board and the board was recognized by the computer once I connected it to the ISP, I only had some problems controlling the position of the resonator. (see image 5# for the image of the complete soldered board)
Once I completed it, I checked for shorts across the board with a multimeter, then connected it to an ISP and using the command "avrdude -c usbtiny -p t44" on my Mac OS X terminal and after learning that 6-pin headers do indeed have an orientation, the message "AVR device initialized" flagged that I had been success. (See image 6#, first message was caused by wrong orientation of pin, second was a successfull initialization)