Mobile printing options
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Mobile printing options

by odin917 on Wed Nov 14, 2012 5:38 pm

Hi, I was looking at the mini thermal printer but I don't think I could get that running on batteries. Does anyone have any ideas for something small (handheld) for printing?
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Re: Mobile printing options

by adafruit_support_mike on Thu Nov 15, 2012 2:19 pm

Batteries shouldn't be a problem.. the printer only needs 5-9v at the supply, and 1.5A while it's printing. A 4-AA battery pack should be able to give you both without any trouble.

The only real challenge would be battery life. AAs hold about 2 amp-hours worth of energy, so you'd only get an hour or so of printing before needing a new set. That's actual 'putting letters on the page' time though, so you could go about 12 hours printing one 5-second message per minute.

Larger batteries would last longer, but then you get into size and weight issues. What are you trying to do?
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Re: Mobile printing options

by odin917 on Sun Nov 18, 2012 11:20 am

thanks for the reply!

I think the batteries will work fine for me then. I am trying to recreate this project I saw on hackaday a while back where a camera used internet access to push images to mechanical turk and then printed a piece of paper describing the image, rather than the image itself.

was going to use, arudino uno, jpeg photo serial camera, data logging kit, and xbee wireless to my mobile phone "hotspot" for internet access. all the rest of the magic i think will happen on a small webserver im running

im very new to arduino but i recently just built a IOT Printer to familiarize myself with the thermal printer.

thanks again!

-gav
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Re: Mobile printing options

by adafruit_support_mike on Sun Nov 18, 2012 5:12 pm

Okay. Sounds like you're looking for something in the 'larger than wearable, smaller than luggable' range. I'd suggest C cells.

Alkaline AA cells are usually rated for 2000 mAh of energy and have a volume of 8cc. Power for volume, you get about 250 mAh/cc. They weigh about 15g, so you get about 133 mAh/g.

Alkaline Cs are usually rated around 8000 mAh, and their volume is 27cc. Power for volume, you get about 295 mAh/cc. They weigh about 66g, so you get about 121 mAh/g.

Alkaline Ds are usually rated around 12000 mAh, and their volume is 56cc. Power for volume, you get about 215 mAh/cc. They weigh about 150g, so you get about 80 mAh/g.

9v batteries suck btw.. they're rated for 600 mAh, and their volume is 21cc.. Power for volume, you get about 29 mAh/cc. They weigh 45g, so you get about 13 mAh/g.

AAs give you the best power-for-weight performance, Cs give you the best power-for-volume. Ds justify themselves when you're willing to accept size and weight to get extra longevity, and 9vs justify themselves when you're willing to sacrifice everything else to get a higher voltage in a smaller volume.
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Re: Mobile printing options

by odin917 on Mon Nov 19, 2012 9:53 am

amazing, thanks!!!!
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