Raspberry Pi noob questions thread

Discussion in 'Raspberry Pi' started by Stitches, Nov 24, 2017.

  1. Stitches 2 and a Half Dollarydoos Staff Member . .

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    What specific amp are you using, and with what speakers?
     
  2. Ewhizz .

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  3. Stitches 2 and a Half Dollarydoos Staff Member . .

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  4. Ewhizz .

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    If I use an RPI 2 max current is 650mA
    With this driver board & 5inch screen:
    https://www.adafruit.com/product/2218

    and a 5inch screen the max current drawn is 500mA total. You can reduce that down 370mA by running the backlight at half-brightness (25mA).
    Teensy 2.0 uses max 28mA.
    The adafruit speaker and amp should use bugger all .

    So that means with a Panasonic 3.6v 3400mah battery , I should get approx:
    Approx 1200ma required from components
    Therefore 3400/1200 = 2.9 hrs of battery life. ??

    Using the powerboost 1000C which outputs 1.8A (adaquate as 1200ma is being drawn) it will take 3400/1000 = 3.4 hrs to charge. ??

    Am I missing anything or stuffing anything up here ?
    Thanks guys
     
  5. notmichaelhill .

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    Hey, so I have a Raspberry Pi 2 Model B, and I had RetroPi installed a few years back. I've barely used it, but now that I've gotten into modding, I want to make a portable version and I noticed that there's a ribbon cable slot for a display screen. What kind of screen should I get? What's the right size? I want to make it small enough to 3D print a protective case and place it on top of my Raspberry Pi case. If you need pictures, I'd be happy to provide them. Thanks for the help, guys!
     
  6. fibbef Wizardry V Completer .

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    Sounds like you’re looking for something like this:
    936D4D3E-40FF-4523-ABB0-97826E090529.png

    Except this uses the pi’s gpio pins instead of the dedicated display connector. I didn’t link to this one since it’s an eBay listing, but I just searched for “raspberry pi screen”. They’re pretty common.
     
  7. FreedomCookie .

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    New to both console modding and RPi here. I'm throwing together my plans for a portable machine running RetroPie on a RaspberryPi B+. I'm doing a GameCube controller layout and looking at the GC+ but I can't tell if there's USB output to solder it to one of the USB ports on the RaspberryPi board.

    Alternatively I might go the Teensy route, which I have yet to know anything about, but I can't figure out which Teensy I'd need. I was planning 16 buttons (ABXY, L/R trigger, dual Z buttons, D-Pad, two Joysticks, and two extra), two analog joysticks and two analog triggers. The GC+ doesn't appear to take as many inputs.

    If anyone can give me more information about either the GC+ or the Teensy so I know which I should choose, that'd be much appreciated!
     
  8. cheese the tallest memer in town Staff Member . . .

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    You could potentially get away with using the pi's GPIO for buttons. There is no USB connection on the GC+, it is specifically made to work as a gamecube controller, not a USB one.
     
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  9. DeoNaught .

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    You can use Rpi's Gpio for game controls(the software I used is called retrogame), But if you plan to use analog sticks, you are going to want to use a teensy.
    since Rpi doesn't do this without some external components
     
  10. Bonicgamer .

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    I've seen some RPi 0 projects where the RPi is soldered to a PCB (Like this project), and I wanted to how that works -like how to get video and audio out- so I can make my own PCB if I ever decide to learn how to make PCBs.
     
  11. cheese the tallest memer in town Staff Member . . .

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    They probably used SPI and I2S for video and sound, the pinout for the header is here

    [​IMG]
     
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  12. Ben_The_Younger .

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    I see that most people use a D-Pad for their handheld Pi systems, but I was hoping to use a Nintendo Switch (joycon) Analogue Stick for directional input and the A button, by clicking it in. Is that possible with retropie? (I'm using a Pi Zero if that's important.)

    I was hoping to avoid using a Teensy, for simplicity and for space. The system I'm trying to make really is tiny. But if that's the only known (or practical) way to do it, then it's fine. I'll just have to go for a traditional D-Pad + A,B buttons for Gameboy. I know Teensy and analogue joysticks were mentioned above, so forgive me if I'm overlapping my question here.

    Another question is about using an unused smartphone battery to supply power. Is that recommended? I'm thinking that the one I have is very thin and has a perfect footprint for my intended project. Once again, I might be a bit optimistic in what I'm trying to do, but if anybody has done that before, I'd like to hear about their experience. I'm not overly concerned about battery life, either so that's not the issue. The battery in question is (or "was") 2800mAh , 3.8 V , Li-ion , made by Samsung for a smartphone from about 6 years ago. I have two of them if that helps with voltage somehow. (electronics noob, forgive me)

    Again, if that's too difficult to execute, I'll have to try a more typical battery setup.

    I have good faith and trust in the advice given on this forum, so I eagerly await some pointers. Thanks
     
  13. GBAGuy007 .

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  14. GBAGuy007 .

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    As far as your battery goes last time I checked the Raspberry Pi Zero takes 5 volts at 1amp (5 watts) so your batteries would need to be run in series to increase the voltage to a max of 7.4v but it has probably degraded over time. Also make sure you include battery circuits and other components with the battery along with the watts (take the screen and and other components into account too)

    Edit: Raspberry Pi Zero runs at .5 to .7 watts which makes my statement of series absolet unless your screen is extremely power intensive.
    https://photos.app.goo.gl/S1YdE1PRouFM2XVf9

    Sorry for double post
     
    Last edited: Jan 24, 2020
  15. Ben_The_Younger .

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    Thanks for the response. I believe my screen takes power directly from the Pi and it looks like it's marketed for the Zero in particular. I've given up on the idea of using smartphone batteries. As convenient as it may be, it's not worth the extra research since I'm such a beginner. I may
    return to the idea one day, but not now.

    I do still want to try an analogue stick instead of a D-pad, though. And Only if it's easy enough.
     
  16. GBAGuy007 .

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    I don't know exactly what games you want to play but if you just need the analog stick as a d pad this guide should help: https://learn.adafruit.com/super-game-pi/overview.
     
  17. Blitz4597 .

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    How would one use/solder a composite screen to the Raspberry Pi 3 b+?
     

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