Klipeti
Posts: 4
Joined: Thu Sep 12, 2013 6:43 pm

My project...

Thu Sep 12, 2013 6:58 pm

Hello everyone!

I haven't used Raspberry Pi, but I have read a lot about it. I have planned a project with it as a project in school, but it isn't confirmed that will I ever do it. I'd like to hear your opinions about it.

So, basically I'm going to make *surprise* Handheld retro console. Here's parts I have planned to use:

Screen: http://www.amazon.co.uk/Monitor-Support ... B006MPRFJQ
Raspberry Pi Starter bundle: http://www.amazon.co.uk/Raspberry-Pi-St ... pi+starter
Battery: http://www.amazon.co.uk/gp/product/B006 ... PJL0BBLHLX

Also, I found this guide: http://lifehacker.com/how-to-turn-your- ... -498561192
I'm going to follow the guide step by step to setup my Raspberry Pi :)

Because I'm a low budget student, I look for cheapest parts.
Here's my questions:
1. I know that screen I chose is used by many Raspberry users, so is it possible to mod it use +5 voltage? There are some projects but they used different screen. I intend to use same USB battery with Raspberry and Screen.
2. Is my battery good for my project?
3. Any advice working with this project?

Ps. I'm from Finland, so English isn't my first language.

technoducky
Posts: 62
Joined: Sat Jan 26, 2013 7:29 pm
Contact: Website

Re: My project...

Mon Sep 16, 2013 12:11 pm

Klipeti wrote: 1. I know that screen I chose is used by many Raspberry users, so is it possible to mod it use +5 voltage? There are some projects but they used different screen. I intend to use same USB battery with Raspberry and Screen.
It probably can be, but it is probably a pain.
Klipeti wrote: 2. Is my battery good for my project?
Not if you want to run that screen.

A fix for both problems is to use some 12v source and a switch mode converter to step it down to 5v, for capacity a battery around the 10000mAH range would maybe give you an hour of usage (very rough guess based on assumed power usages).

Klipeti
Posts: 4
Joined: Thu Sep 12, 2013 6:43 pm

Re: My project...

Mon Sep 16, 2013 4:43 pm

Hello again.
Thanks for the answer.

I have been looking different internet stores and my current choice of parts is this:

Screen: http://www.ebay.co.uk/itm/3-5-TFT-640-4 ... 5af16a0c94

RasPi: http://www.ebay.co.uk/itm/RASPBERRY-Pi- ... 27ccc482f3

Battery: http://www.ebay.co.uk/itm/New-Black-120 ... 232cde6bb6

I found out that few people have modded 3.5" screens to use +5 voltage :)
http://www.wisegai.com/2012/11/29/raspb ... using-usb/
http://www.raspberrypi.org/phpBB3/viewtopic.php?t=17651

About battery, knowing that it should be 12000mAh, Raspberry Pi model B uses around 3.5W, and the screen's store page says "Power ≤ 4W" so wattage is around 7.5W.
Battery's Wh = mAh × V / 1000, so I can say 12000mAh * 5V / 1000 = 60Wh. Now we can get hours of use: 60Wh / 7.5W = 8h. Not knowing how much is the real mA or quality of battery, I'd say battery lasts around 6h.
I'm not math pro, so I can be wrong.

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