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Can anyone draw me a schematic? Answered

Hey Guys, its been a while since a posted a question.... Anyway I was wondering if anyone could draw me a schematic from this video:

https://www.youtube.com/watch?v=9DJTkasvgzo


Oh and remember to add a zener on the usb output hub of the charger because I think you need that to prevent the phone from sending energy back after the batteries are drained.

Thanks in advance.
-Prickly Potato

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Jack A Lopez
Jack A Lopez

Best Answer 5 years ago

Hey, I finally got around to watching that video, and I'm not all that impressed by this project.

To me, it looks like a confused mess, and not worth copying.

The most troubling part is this stack of eight AAA batteries, in a battery holder that's wedged into this box so tight that it would be difficult to remove. Then in the event the user does have to remove it, like when the batteries go dead, there are eight of the goofy little things to replace, necessary for to refuel it.

I don't know if you youngsters are old enough to remember Ladyada's original MintyBoost(r), a 5-volt USB charger, powered by 2xAA batteries. That instructable was upped

https://www.instructables.com/id/MintyBoost!---Smal...

way, way back, in the year 2006. And even back then, in the olden days, that project was really more effort than it was worth, because it was (I think) possible to find the same thing (5-volt USB charger, powered by 2xAA batteries) in mass-produced, molded plastic form, for a price of about 10 USD.

Naturally, the mass-produced plastic version did not look as hip as something homemade and in a metal Altoids(r) case.

But then if you wanted to have the Altoids(r) skin, you could just take all the parts from the mass-produced plastic version, and hot-glue them into an Altoids box.

You know, so it would look cool. ;-P

Back to the subject of smithba76's Altoids-skinned Roadwhatsit: Have you wondered why it is he's using a stack of 8 AAA batteries (nominally 12 volts) together with a boost converter? It's not a rhetorical question. I honestly don't know why he is doing that, since for a boost converter Vin is strictly less than Vout. I dunno. Maybe he's just using the word incorrectly, and the converter is actually a buck/boost (works for Vin <,=,>Vout), and just maybe it is this one:

https://www.pololu.com/product/2118

That's a guess. The only clues he gives us: he says he got it from polohu-dot-com, Vout is adjustable, and he's powering with a stack of 8 alkaline batteries. I mean this guy is way too cool to actually provide us with a link, or a product number, or anything like that. He's also too cool to remember that brown-black-yellow-gold means 100 K ohms, which says to me that he's kind of a noob.

Anyway, I think this box would be superior if it could be refueled by a small number (like 1 or 2), of the larger, AA batteries, in much the same manner as the original MintyBoost(r), or any of the good copies that followed it, e.g.

https://www.instructables.com/howto/minty+boost/

As for all the other junk: the thumbdrive, the bluetooth, the LED flashlight, I mean, sure, you can do that, and you figure out how to wire it yourself. You really can.

Final note: I do not believe a diode, zener or otherwise, is a necessary part of the output circuit. I mean, I don't really see, erm comprehend, what that is supposed to do.

I claim, without proof, the phone's charger circuits are smart enough to avoid "sending energy back", even if the event the charger output suddenly turns into something weird, other than a 5-volt supply (like a short) in the process of the charger's batteries being drained.