Is this possible/how much power do I require?


17 posts
by Music Guy123 » Thu Apr 12, 2012 6:20 pm
Hi there,

I am very excited as I will be getting a raspberry pi for my birthday! Or at least whenever they are available again! Now, I have got something I really want to do with my raspberry pi, and was wondering if it was possible. I am trying to make it completely portable, screen included. Battery life isn't too much of a problem. My main concern is the screen, I have found this: http://compare.ebay.co.uk/like.....#038;cbt=y Anyway, I looked up the power requirements and I found that it has an input of 5v 500ma and a consumption of 2-4.5w would that make sense? Have a look here: http://www.avsaleseurope.com/m.....i-tft.html Finally, if it does work, how much do I need to power the raspberry pi? I have a 1A usb charger, I am sure I can find another if more power is needed though. How much power do I need? I will be running a small external HDD of the thing as well if possible.

I hope you guys are able to help,

Music Guy
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by ghans » Thu Apr 12, 2012 9:06 pm
Hmm.
What do you mean by portable ?
Do you plan to use one of these big USB battery packs with 2+Ah ?
You could buy a tablet for that price ... (40+ $ - taxes - for RPi , 90 $ for display , 70 $ for battery pack , 20 $ for cables "n" stuff , loads of your time ...)
Android tablets can be rooted , have a tested SDK ...

Take one of these super-powered 2A USB Hubs - the Pi may take 3.5 W + 2-4 W Screen : too much for 1A x 5V.
It is possible ...
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by Music Guy123 » Thu Apr 12, 2012 9:34 pm
Portable means can I watch a movie on it in a coach with not electricity supply really. The reason I am going for this method is that I can put an external HDD in because my iPod classic isn"t big enough for my collection. I really just want to use this as a cheap portable computer. So, say I needed 7.5w at maximum, I am going to need a power supply that can provide 1.5A right? Thank you for replying, it is much appreciated. Anyway, for a start, I will just be getting the pi. Then, if funds allow, the screen. I"ll get it setup to run of a cig lighter, that won"t be a bad achievement and will be fine for me. So, thank you again.

Music Guy
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by ghans » Fri Apr 13, 2012 7:49 am
So no USB battery pack then ?
Take a 2A power supply anyway - you want headroom for your external disk and whatever. Might drain your car battery fast , though. (Use SSD ??)

Anyway , note that many tablets have USB Host - you can plug in HDDs , pendrives and even cardreaders.

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by Music Guy123 » Fri Apr 13, 2012 8:11 am
Yes, you have a point with using it as a tablet. I have an external HDD, I need plenty of space, SSDs are too expensive and if I did get one, I would use it in my laptop, IMO, using it as storage in a pi is a little of a waste. I think I will just have it as the pi and the external hdd and then use a screen somewhere else. If I really want to, I can always get those backseat ones for a car and power it externally. Thanks for the help though. I know I have a 1a USB power supply, surely that will be enough for the pi as long as the external hdd doesn"t draw much more than a watt of power right? Anyway, thanks again, I am sure this question has been posted billions of times but eta? I mean next week, next month, 6 months time, 2013. I just would like a rough idea of when it is expected to come back into stock. Thanks for all the help again.

Music Guy
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by viciouspenguin » Fri Apr 13, 2012 8:49 am
you could always go for a screen like this....

http://www.ebay.co.uk/itm/7-TF.....3f159f2a34

I bought a similar one, which I am in the process of mounting into the sunvisor of my 4x4. The screen will be connected to a dash mounted laptop and will show gps navigation information. They are low powered as the backlights are LED. The controller board has VGA in. if you hunt around you should be able to find a board with HDMI in like the one I have.
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by Music Guy123 » Fri Apr 13, 2012 9:02 am
viciouspenguin said:


you could always go for a screen like this….

http://www.ebay.co.uk/itm/7-TF.....3f159f2a34

I bought a similar one, which I am in the process of mounting into the sunvisor of my 4x4. The screen will be connected to a dash mounted laptop and will show gps navigation information. They are low powered as the backlights are LED. The controller board has VGA in. if you hunt around you should be able to find a board with HDMI in like the one I have.


That looks brilliant, one problem though, I am in the UK! I will have a search around though. Also, could you use the av input? It isn't that high a res. Thanks for helping everyone, it is so much appreciated!
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by viciouspenguin » Fri Apr 13, 2012 9:22 am
Music Guy123 said:


viciouspenguin said:


you could always go for a screen like this….

http://www.ebay.co.uk/itm/7-TF.....3f159f2a34

I bought a similar one, which I am in the process of mounting into the sunvisor of my 4x4. The screen will be connected to a dash mounted laptop and will show gps navigation information. They are low powered as the backlights are LED. The controller board has VGA in. if you hunt around you should be able to find a board with HDMI in like the one I have.


That looks brilliant, one problem though, I am in the UK! I will have a search around though. Also, could you use the av input? It isn"t that high a res. Thanks for helping everyone, it is so much appreciated!



they will ship to the UK, I'm in Derbyshire.
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by Music Guy123 » Fri Apr 13, 2012 9:25 am
Oh right, ok, thanks. Where did you manage to find your HDMI board?
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by viciouspenguin » Fri Apr 13, 2012 9:50 am
Music Guy123 said:


Oh right, ok, thanks. Where did you manage to find your HDMI board?


ebay, but the people who I bought it off arent on there anymore, I had planned on giving you their details but alas they are no more.

the model number from the screen is AT070TN92 and the controller board UT-2668-N2

EDIT: found the screen and controller board matched up on ebay

http://www.ebay.co.uk/itm/VGA-.....2a1b6e7fd6
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by Music Guy123 » Fri Apr 13, 2012 10:16 am
Wow, thank you very much. One thing though, do I have to have it with the touch panel? This isn't a problem, I just don't see how it would connect to the pi. Also, would touch screen be compatible with the linux oses? Thank you very much for your help so far, I can't tell you how much I appreciated it!

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by tufty » Fri Apr 13, 2012 11:13 am
Touch screens are relatively easy to find (depending on screen size, look at some of the netbook touchscreen hacks), but you"ll need one with a controller included rather than a "raw" panel. That means (probably) another USB device, so more power draw.

The more stuff you start adding, the less good the pi looks in terms of integration and cost against an off-the-shelf tablet, tbh.
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by Music Guy123 » Fri Apr 13, 2012 11:53 am
I"d agree. I don"t want the touch screen, I am trying to find a screen like the one shown in the last link. Or, to get a screen controller then get an old laptop screen? What do you think? I will post a link in a minute with some controllers I found.
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by davesedar » Fri Apr 13, 2012 12:32 pm
I am planning to use a sat-nav as the r-pi screen in car (http://www.ebay.co.uk/itm/3208.....428wt_1185)

you get gps thrown in for 'free'.

Hopefully powering both from a 2-USB port cigarette lighter socket adapter (http://www.ebay.co.uk/itm/2509.....850wt_1089).

Will let you know if (when) it works OK.
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by Music Guy123 » Fri Apr 13, 2012 12:39 pm
davesedar said:


I am planning to use a sat-nav as the r-pi screen in car (http://www.ebay.co.uk/itm/3208.....428wt_1185)

you get gps thrown in for 'free'.

Hopefully powering both from a 2-USB port cigarette lighter socket adapter (http://www.ebay.co.uk/itm/2509.....850wt_1089).

Will let you know if (when) it works OK.


That looks like a perfect idea. I am very interested! Don't know whether touch screen is going to work with the pi but that won't matter too much. I'd love to know how it turns out, please send me a pm when you are able to do it. Do you know when you are going to be able to do it? If this works then I am sold, thank you very much for the help from everyone.

Music Guy
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by davesedar » Fri Apr 13, 2012 12:53 pm
Music Guy123 said:


davesedar said:


I am planning to use a sat-nav as the r-pi screen in car (http://www.ebay.co.uk/itm/3208.....428wt_1185)

you get gps thrown in for 'free'.

Hopefully powering both from a 2-USB port cigarette lighter socket adapter (http://www.ebay.co.uk/itm/2509.....850wt_1089).

Will let you know if (when) it works OK.


That looks like a perfect idea. I am very interested! Don't know whether touch screen is going to work with the pi but that won't matter too much. I'd love to know how it turns out, please send me a pm when you are able to do it. Do you know when you are going to be able to do it? If this works then I am sold, thank you very much for the help from everyone.

Music Guy


Hi,

I have just ordered the cigarette lighter socket power supply, and have a bid in for the sat nav. The r-pi is on order from Farnell.

Regarding the touch screen - obviously the sat-nav has one for its own purposes (it runs Windows CE), I was hoping there might a windows CE app to run a soft keyboard on it so r-pi sees it as a keyboard via USB port.
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by Music Guy123 » Fri Apr 13, 2012 1:23 pm
Well, best of luck, I am not sure whether the touch screen would work but there is a possibility it might. I look forward to hearing from you about it. Have you actually ordered your rpi? I thought they weren't in stock again yet. As for the sat-nav, best of luck with your bidding, I see you aren't going for the safe 'buy it now' option! I look forward to hearing from you.

Music Guy
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