Yet Another Pi Zero Portable!!

moosepr

@obsidianspider well now I know it works, I'm going to be designing a few different things that stick a pi and a screen in the smallest package possible. Watch this space........

gazredtyke

hi Peter,

you wouldn't happen to have a parts list with links would you? I'd like to try to build something like this but I'm a bit of a NOOB with the electronics side of things.
Thanks

moosepr

@gazredtyke I think there may be the details peppered though the thread. It is basically a pi zero, 8 buttons and a TFT screen. It's all wrapped rather haphazardly around a lithium battery, with a charge/protect PCB, and a microcontroller doing a bit of switching

gazredtyke

@moosepr I've ordered a screen from china, I've got a few pi zero's, I've found the li po charge protector but I couldn't find the microcontroller, also will any li po battery around 2000 mAh do? Do you reckon I could use the guts of a usb snes controller for the input?

moosepr

@gazredtyke with my testing, 2500mah got me 10 hours, so 2000 will get you about 8 hours.

The microcontroller is a uhex from dfrobot https://www.dfrobot.com/wiki/index.php/UHex_Low-power_Controller_SKU:_DFR0343

I did plan on adding a power level indicator and safe shutdown of the pi, but never got round to it. You could replace the microcontroller with a simple switch really

The controller route is a good idea, the PCB will have one side of each switch going to a common point. This will need connecting to one of the gnd pins on the pi, with the other side of the switch being connected to individual gpio pins

gazredtyke

@moosepr thanks for that, I've got a 5200mah power bank that I don't use, would that just be too much?

moosepr

@gazredtyke the only thing you need to watch with batteries is the voltage. If you use the power bank USB output then you will get 5v, but you will loose some of that capacity with the conversion. If you crack it open and use the raw cells you will get more capacity, but only get 4.2-3.3v from the cell. You can put anything as low as 3.3v into the 5v pins on the zero and it will work fine, but anything over 5v and the magic smoke will come out. The capacity will only alter the runtime. A 5000mah battery will just get you 20 hours runtime

gazredtyke

@moosepr it says 3.7V 5200mAh 19.24Wh on it

moosepr

@gazredtyke awesome, that's just under 21 hours runtime then! Will probably take like 6 hours to charge though! 😛

gazredtyke

@moosepr overnight then! haha, would you mind if I got in touch when my parts arrive for some help?

moosepr

@gazredtyke yeah no problem dude! If you start a post detailing the build, you will get lots of help from everyone!

gazredtyke

@moosepr thanks mate, could you let me know which gpio pins are needed for all the connections? Can't quite make it out from the photo...

moosepr

@gazredtyke I used this as a guide to connect the screen
http://marcosgildavid.blogspot.co.uk/2014/02/getting-ili9341-spi-screen-working-on.html?m=1

Then the buttons, you can use any of the remaining gpio pins. You have to install some software on the pi that turns your pin input into keyboard commands, and in there you set what pin does what

gazredtyke

@moosepr I think I've thought of another way, if i desoldered the micro usb I could just solder the usb wires directly to the pi couldn't I?

gazredtyke

@moosepr infact scratch that, ridiculous idea!! I've just soldered 5 wires to a micro usb male, still smaller than the screen and battery when plugged into the micro usb port!

rockyhill

This is exactly what I need! I'll be making something like it when I get my hands on a zero. Have you played legend of zelda nes?

moosepr

@rockyhill only briefly, might have to have another go now

zelda

rockyhill

@moosepr
Oh man! 10 hours you say? great for trips.
Now one has to convince airport security to let something like this onto an air plane.

moosepr

@rockyhill yeah it managed to sit running the start movie on one of the n64 banjo kazooie games for 10 hours, although the controls stop working. I think the gpio buttons don't get a look in once the CPU goes full speed for n64

i am working on something that looks a little less dodgy. Waiting for the postman to come with my latest OSHpark order

gazredtyke

@moosepr Hi again, as I said I would I have started a similar project, my idea to rewire a cheap usb snes controller worked, I've replaced the regular usb male with a micro usb male, I've tested it with my battery and the LIPO charger module, retropie showed up on my monitor and I configured my controller without issue. I have a couple of questions though....
Do I need the df robot microcontroller? What purpose does this serve exactly?
Also I order a 2.8" tft but it must be slighlty different to the 2.2" screen you used. The pins are different to the ones in the link you sent me, also it's a touch screen, is this an issue?