Yet Another Pi Zero Portable!!

gazredtyke

@moosepr can you show a diagram of which gpio pin layout you followed? Maybe that's the issue?

moosepr

@gazredtyke the error seems to suggest that it doest like the options being passed into the fbtft device call. my command scroll back doesnt go far enough back to see my initial testing bits. I need to go back to a fresh install of retropie and follow it all from the beginning.

If my new 2.2" screens ever come from china, i will be setting up another pi and will detail the lot

gazredtyke

@moosepr could you show the gpio layout? I seem to have 2 different ones 😮

moosepr

@gazredtyke im pretty sure that i used

Display - Raspberry Pi
BL - pin 12
SCK - pin 23
MISO - pin 21
MOSI - pin 19
CS - pin 24
RST - pin 22
D/C - pin 18
VIN - pin 17
GND - pin 20

pinz

gazredtyke

@moosepr I've got the same with the exception I don't have anything on miso as that one is for the sd card isn't it?

moosepr

@gazredtyke that is what it said in the original link I sent you, but I'm pretty sure I linked the pin on my screen. I squashed the wires so it's hard to follow which is which, but I do seem to remember filling most of that block of pins on the pi

gazredtyke

@moosepr so maybe if I wire the miso to the pi?

moosepr

@gazredtyke give it a go. I'm pretty sure the only pins that are shared between the screen and the SD card are the power ones (but I could be wrong)

gazredtyke

@moosepr no joy 😭

moosepr

@gazredtyke this works for me

sudo modprobe fbtft_device custom name=fb_ili9341 gpios=reset:25,dc:24,led:18 speed=16000000 bgr=1

gazredtyke

@moosepr thanks, I'm out tonight but I'll try that after work tomorrow, failing that I've found an instructable using the same screen

AluLagoa

First of all, sorry for the necro...

Great work!
This inspired me to make my own portable.

So, you run your setup straight from the 3.7v 2000mah lipo. How much play time does it give you?

moosepr

@AluLagoa necro!! ha ha!!

I did a runtime test, launched an N64 game and let the intro video run, so the pi should have been working pretty hard.

I got 10 hours on the test, but im not 100% sure what capacity the batteries are. My usb power meter claims it was 2500mah that the battery took to get to full, although this is sometimes misleading, as the voltages are different.

if we multiply the 5v charge by the 2500mah current (2.5amps) we get 12.5 watts. now the battery will actually be taking 4.2 volts to charge, so divide our wattage by our voltage actually gives us 2.98 amps, so its possible it is actually a 3000mah battery!

AluLagoa

@moosepr Thanks for the info!

I am planing on doing a similar project, but inside a case of some sort.
Have you ever updated your build to be inside a case?

moosepr

@AluLagoa i did intend on popping the guts inside a GBA case, then i got sidetracked trying to reduce the pcb overhang so i could get the 2.8" ili9341 to work, then i got carried away making custom pcb's to join a pi and an ili9341, and kinda forgot my initial project!!

AluLagoa

Regarding the battery.
People on a FB group are insisting that i need 5V 1.2A to power the 0.
But i can see from your project that a 3.7V lipo can handle it.

So, is it safe to run a 0 directly from a 3.7V lipo?

moosepr

@AluLagoa well I have never had an issue. The internals of the pi run at 3.3v or less. The main reason why there is the 5v input is because it is the standard for usb devices, so to be sure any usb device can work, we need 5v.

That said, some usb devices don't really need 5v, I have wireless and memory sticks that are fine at lipo voltages.

I think the main reason why 1.5 amp power supplies are recommended is to account for full power zero, with a camera, and some devices on the usb.

With a simple TFT and zero setup like this, it's only drawing 300mA, so as long as you battery can safely deliver that, your golden. Just watch out for low battery situations, the pi will start acting weird below 3v, and the battery shouldn't really be taken below that anyway, or you will damage it

AluLagoa

@moosepr Thanks again for the info.

As this is my first handheld, decided to go with external power from a power bank. In a future build I will implement internal power.

moosepr

@AluLagoa yeah they are a great way to get power easily! And they look less dodgy in airport security! 😛

retroprogrammer

@moosepr Can I ask you which tutorial exactly, you followed to connect the TFT screen