Last night was rather frustrating. How hard could it be to get a simple microphone working? Apparently it can be rather hard.
The tricky device was a very small microphone (4 pad QFN package) , specifically the Knowles SiSonic surface mount MEMS microphone. Since it only has 4 pins, it seems like it can't be that difficult. But, it was. This is the website:
http://www.knowles.com/search/products/m_surface_mount.jsp
After a few hours of tinkering, it turns out there is just not enough gain in they system. The microphone should be connected to a variable resistor to control the gain, but we found out the microphone works if the resistor is shorted, hence creating the maximum possible gain. Even then, it would have been nice to have more gain -- something to think about in the next circuit?
Tuesday, October 6, 2009
Monday, October 5, 2009
Lesson 2: Design for Visibility
In order to succeed in any venture, you'll have to overcome obstacles. Some of these are technical, and some of them are interpersonal, business, etc. This is my forum for describing all sorts of obstacles I ran into.
Lesson 2 is to design with visibility in mind. As parts get smaller and smaller, it is much harder to determine if it is a solder problem and if the pins are connected or not. Solutions around this could include:
1. Design pinouts/fanouts into the PCB board such that you can probe signals under a QFN.
2. Use a breadboard to get the software working for discrete components. For example, if you are trying to get a QFN microphone working, then you should be able to write the software and test the microphone with a breadboard or some sort of easy layout to make sure the software works and it is not a solder issue.
Lesson 2 is to design with visibility in mind. As parts get smaller and smaller, it is much harder to determine if it is a solder problem and if the pins are connected or not. Solutions around this could include:
1. Design pinouts/fanouts into the PCB board such that you can probe signals under a QFN.
2. Use a breadboard to get the software working for discrete components. For example, if you are trying to get a QFN microphone working, then you should be able to write the software and test the microphone with a breadboard or some sort of easy layout to make sure the software works and it is not a solder issue.
Lesson 1: More than 1
In order to be successful at any project, I believe you need to have more than 1. More than 1 person working on your project, more than 1 person believing in you. In otherwords, you need a team. I'm not talking about a committed team who has as much passion about your idea as you do, but I am talking about someone who can lend a hand when necessary. You need a team member to bounce ideas off of, to listen to, and to give you the occasional positive encouragement when things just aren't going your way.
For a literal example of this, tonight I needed an additional hand to solder 4 wires onto a discrete part. I could get most of them on, but everytime I tried to get all 4 wires on, the other ones would fall off. With my teammate holding the wire for me, it worked the first time. Lesson learned.
For a literal example of this, tonight I needed an additional hand to solder 4 wires onto a discrete part. I could get most of them on, but everytime I tried to get all 4 wires on, the other ones would fall off. With my teammate holding the wire for me, it worked the first time. Lesson learned.
Welcome
Sometimes life can seem unfair.
In college, the opportunities seem endless, with many job possibilities out there, just waiting for you to come and succeed. As a college student, it seems that you can find the perfect job, with a good salary and a great team as icing on the cake.
But then you hit the real world. And you get a job which initailly seems awesome. You have a good salary, and a good team, and you get to keep learning as you contribute to a big company. But after a few years, the awe and wonder starts to wear off... you realize that you are always working for someone else, someone else's company, and although you are getting a paycheck, there is something inside of you that wants more. You want more challenge, more ownership of your life, and more excitement. And hence the inventor and entrepreneur are born....
In college, the opportunities seem endless, with many job possibilities out there, just waiting for you to come and succeed. As a college student, it seems that you can find the perfect job, with a good salary and a great team as icing on the cake.
But then you hit the real world. And you get a job which initailly seems awesome. You have a good salary, and a good team, and you get to keep learning as you contribute to a big company. But after a few years, the awe and wonder starts to wear off... you realize that you are always working for someone else, someone else's company, and although you are getting a paycheck, there is something inside of you that wants more. You want more challenge, more ownership of your life, and more excitement. And hence the inventor and entrepreneur are born....
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