Home > BrewzNET 2.0, Tech geeks > Mainboard Shield Ordered

Mainboard Shield Ordered

mainboardmainboard-bottom

I simplified the mainboard from my previous post. I’ve been having problems getting steady signals from the XOR CMOS chip and tracked it back to an issue with nearly all of my signal converter boards from Sparkfun. I don’t know exactly why, but the output from Channel 1 always seems to be weak and the CMOS IC has a hard time determining whether it’s a high or low signal – so it flickers between the two. I was using that converter to scale the 3.3V signal from the Netduino up to a 5V signal, but after doing some testing I found that is completely unnecessary. The output from the XOR chip is much better and rock-steady when driven directly from the Netduino pin, even though it’s mixing a 5V signal from the override switches and the 3.3V signal from the Netduino. Simplification is a good thing, right?

I placed the order for the boards this morning. Hopefully that means they’ll be in the mailbox in about 2 weeks. Upon further reflection I suppose I could have shifted the resistors up into the vacant space previously occupied by the signal conversion board and made the entire shield footprint smaller (and cheaper by probably $5-10), but it’ll be a standard shield size and shape for now. If I find the board needs revision I’ll make the change at that point.

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Categories: BrewzNET 2.0, Tech geeks
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