Changes between Version 3 and Version 4 of Prototype/One


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Timestamp:
07/05/10 19:14:24 (14 years ago)
Author:
art
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  • Prototype/One

    v3 v4  
    33Ok, it is winter time and it is cold outside, and I started to build the first prototype. The problem is, that I am working only in my free time, so I have not much time to spend on this project. Therefor it just continues slowly. Ok, nevermind, let's rock. First of all, take care of the size for the self-made PCBs where I will put my prototype on: 
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    5 [[Image(http://www.tevs.eu/media/images/projects/openbm/DSCI2740.JPG, 400px)]] 
     5[[Image(http://www.tevs.eu/media/images/projects/openbm/DSCI2740.JPG.small.jpg, 400px)]] 
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    77Next thought was, how to connect that board. I decided to do it cable, by cable, in this way: 
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    9 [[Image(http://www.tevs.eu/media/images/projects/openbm/DSCI2742.JPG, 400px)]] 
     9[[Image(http://www.tevs.eu/media/images/projects/openbm/DSCI2742.JPG.small.jpg, 400px)]] 
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    1111Which ended up in a disaster of cables. The connections were unstable and everytime I moved the small PCBs the connection even breaked down. So, don't even try this. I had to make this experience, to make it next time better: 
    1212 
    13 [[Image(http://www.tevs.eu/media/images/projects/openbm/DSCI2805.JPG, 400px)]] 
    14 [[Image(http://www.tevs.eu/media/images/projects/openbm/DSCI2948.JPG, 400px)]] 
     13[[Image(http://www.tevs.eu/media/images/projects/openbm/DSCI2805.JPG.small.jpg, 400px)]] 
     14[[Image(http://www.tevs.eu/media/images/projects/openbm/DSCI2948.JPG.small.jpg, 400px)]] 
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    1616The board is driven by an [http://www.atmel.com/dyn/resources/prod_documents/doc2503.pdf ATmega32] uC with 32K flash memory by 14MHz. As connection to BMW's bus-system (i.e. I-Bus) I am using [http://www.google.de/url?sa=t&source=web&cd=1&ved=0CBkQFjAA&url=http%3A%2F%2Fwww.melexis.com%2FAsset%2FTH3122_Datasheet_DownloadLink_4788.aspx&ei=ZREyTKn2EoetONrvqfAB&usg=AFQjCNFLf0Z4rJZiAKVNMJYI394pmVMHSg TH3122] chip from Melexis. 
     
    1818After trying several things, I just didn't came up to a good result, because this amount of cables was just unhandable. The comparison of the PDIP and TQFP package of the same uC shows the differences, so I had to get everything smaller, otherwise the project will not survive. In the right part of the image, you can see the differences in sizes between TQFP and PDIP package of the ATmega32 microcontroller: 
    1919 
    20 [[Image(http://www.tevs.eu/media/images/projects/openbm/DSCI2949.JPG, 400px)]] 
     20[[Image(http://www.tevs.eu/media/images/projects/openbm/DSCI2949.JPG.small.jpg, 400px)]] 
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    2222 
    2323So the next step would be to make everything smaller and handy. Hence, I started a development of SMD based board which would replace this messy wirings. See, next chapter. 
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