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This is a blog about our everyday exploits in all aspects of everything. From science, art, computing, engineering, playing badminton to even playing computer games. Just about everything!

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Archive, November 2014. Switch to list view

    Posted by on in Development, Software and Tools

    This blog post is about determining the value of the base resistor of a MMBT3904L, which is ON Semiconductor's variant of the general purpose 2N3904 NPN  Bipolar Junction Transistor (BJT), when used as a switch. The value is determined when the transistor is in the common emitter configuration. Sounds like a simple task and so it should be too. However, as we have commented many a time in our blog posts tasks that appear to be easy never are.  Hence, while undertaking this task we decided to follow Lao Tzu's (Who? - Ed) advice, which he elegantly formulated in the following quote: 

    Do the difficult things while they are easy and do the great things while they are small. A journey of a thousand miles must begin with a single step - Lao Tzu.

    So, as he has suggested the sensible approach in determining  the value of the resistance of the base resistor of a BJT is to perform the calculation a step at a time, as we demonstrate below.

    Last modified on

    Posted by on in Robotics Using FPGAs

    This blog post describes the analysis and component selection stage of the multi-channel servo controller board design and it is during this stage where, sadly, for most of us it all begins to go wrong.  It is during this process that every datasheet must be read and reread again and again, until every line of text and every curve in a graph is thoroughly understood. It is at this stage that some, out of despair of a looming deadline, decide to fall on their knees, look skywards and utter words of reverence, utter words of importance or just words.  

    It is at this stage that others decide it  is time to put on their jeans and T-shirt and lock themselves in their study. Only to emerge  a few days later wearing a robe and sandals. As you will find out in this blog post we chose to put in a few night shifts to resolve the recurring problems in the design and felt justified emerging with our guru's attire. However, we have known some at this stage of the design process to decide that X marks the spot and continuously aim their heads at it, ceremoniously. Entertaining as this method could be, we prefer ours. However, we recommend you should choose the problem solving method that works for you!

    Last modified on

    Posted by on in First Impressions

    To me all similarly priced servo motors look the same and promise the same performance and maybe they ought to, too. So amongst all the servos out there how do you choose that perfect one for your application? Well, I suppose that is the question that needs answering! Quite fortunately when I had to answer that question, of which set of motors to choose for the 17 Degree-of-Freedom (DOF) robot project, the Tower Pro MG996R motors came recommended, as part of the 17 DOF robot kit. Hence, these motors were thrust upon me.  

    The predecessor to this motor, the MG996, did not receive the most glowing of reviews and was particularly noted for its lack of accuracy and centering. However this version is meant to be a worthy successor with a redesigned PCB and Integrated Circuit (IC) control system, which makes it more accurate. We provide an insider's view of this servo in this blog post.

    Last modified on

    Posted by on in Development, Software and Tools

    If you like a blog post with a happy ending then this blog post has one, but only just. This particular post is about me against Yosemite (10.10) when attempting to install Bugzilla. This time  I won, but barely and the victory wasn't pretty to see. All the same I won albeit with a complete lack of composure at the end. 

     With two big projects coming up I just had to get Bugzilla working, no matter what. So finally getting it to work was more out of desperation than  anything else. Although, because it took so long it did mean that I was not able to begin some other work, as planned. Anyway enough of the waffle here is the story, as it unfolded.

    Last modified on
    Tagged in: Mac OS X Yosemite