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Wiring diagram issue - AA noted in text, AAA noted in diagram #16

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ttsumibishi opened this issue Jul 29, 2018 · 2 comments
Open

Wiring diagram issue - AA noted in text, AAA noted in diagram #16

ttsumibishi opened this issue Jul 29, 2018 · 2 comments

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@ttsumibishi
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Hi there -

I noticed in the diagram, 4xAAA are shown, but you write that they should be 4xAA enerloops. I assume it's AA to provide enough voltage, but is that the case?

Also is it specifically four of them to power both the printer and the RPI?

There's also a line running from what looks like 3v3 power to the other positive rail on the breadboard. Is this correct, and why?

Thanks!

@tgryffyn
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I'm somewhat of a novice in some of stuff stuff, but traditional AA and AAA are the same voltage.. just different capacity. Seems the note about using Eneloop rechargeables makes sense based on the power draw of the Pi and printer, but it sounds like both AA and AAA would work, voltage-wise, but AA would give you more capacity.

Four should give you between 4.8V and 6V, wired in parallel should give the proper voltage to both. I haven't tested mine with the printer, yet, but I assume if it worked for the author of this writeup, it's likely good.

The 3V on the Pi pin 1? Yeah.. I was wondering about that, myself. Unless there's some special hacker trick that isn't obvious, I don't believe that does anything since it connects to nothing.

@danmacnish
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@ttsumibishi sorry for taking a while to get to this - @tgryffyn is correct. I used AA eneloops for the additional capacity. You may be able to get away with AAA, however I've not tested this. The only risk is that AAA may not deliver enough inrush current to the thermal printer.

Good point about the 3V3 line connected to the breadboard - this is a mistake, and should not be there.

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