Yet Another Pi Zero Portable!!

moosepr

just a quick heads up, they are in stock currently

https://shop.pimoroni.com/products/raspberry-pi-zero

senkun

Awesome! Good to hear that even loaded up with wifi it still runs. 240x320 is the best resolution to run our games at, esp off these tft spi screens. Pretty good framerates, minimal tearing and very sharp. All my Pis are self contained units with little tft screens, I have an A+ with a 2.2" so yea a tad on the tiny side, my eyes are coping now but I think in another year or two they won't. Ha. 2.4" or 2.8" would be ideal.

And good to hear too that the uHex is just a glorified switch (for now), means I can just omit it in my future super minimalistic build! But since you have it it would be fantastic to put in more functionality; push button to power up and automatic shut off power supply after the Pi is shutdown and automatic graceful shutdown of the Pi when the button is pushed again and when the power is low (to stop SD card corruption).

Yea, original GB Micros are expensive nowadays. What I had in mind was to rip the case and buttons off a cheapo clone, maybe add more buttons and repaint it. All for around $15 from the usual suspects, or even cheaper if you wait for the slow boat from China.

alt text

senkun

@moosepr

One more thing, is the 2.2" tft one of those with a sdcard slot on the back, running off a ILI9341 driver?

moosepr

Yeah it was this one

http://www.ebay.co.uk/itm/161862594139

Basically the cheapest I could find in the UK. I desoldered the SD card socket from the back to remove some bulk.

I did ponder the tiny generic console route, I have a 1000mah battery that should yeald about 5 hours run time. or i could use a Gameboy advance case and add 2 maybe 3 batteries and get up to 30 hours run time. Although I managed to nab a second pi zero, so I could do both! :-)

senkun

@moosepr

Ha. Thanks for the headsup! I finally managed to grab a Zero and for just £4 too. Can't wait to play with it. And thanks for the link, the UK seller is wonderfully descriptive and knows his stuff. Screen is twice the price of those from China tho, but I'll buy one from him just because.

moosepr

Yeah pimoroni are really good. I ordered the newer version of the zero at 9am on the day it was released, and it arrived the next day.

I normally order my random bits from dx.com, but the 2 week wait for the post made me get the one I did. I have pondered getting a raw screen, then getting a custom PCB made up to contain the buttons and everything, but my PCB design skills are worse than my 3d print design. That would be the holy grail of a tiny handheld though

moosepr

So the postman came!

Toys!

It's actually closer that I thought size wise

senkun

@moosepr said in Yet Another Pi Zero Portable!!:

So the postman came!

Toys!

It's actually closer that I thought size wise

Whoa! Nice! Almost a perfect fit. But then, seems like you need at least a 3.2" screen. Maybe a 3.5" would be best but you'd need to go composite for that size up, gpio 3.5" screens @ 320x480 are too slow.

moosepr

Yeah the original screen is 2.9" so if I bump the screen up to a 2.8" SPI screen, I will keep the same resolution and it should just drop in.

I had a stroke of luck with the buttons, the top of the rubber conductive buttons are exactly the same height as my silicone topped switches. I think I'm going to cut some non conductive sheet of some kind to the same shape as the current motherboard and wire them all in that way.

moosepr

I tried a 2.8" tft i have on an arduino shield, and its almost perfect for the job. The actual display area is a few pixels taller than the hole, and a few pixels narrower, so with some slight mods, it should fit nice!

Im actually struggling to find a 2.8" version of my screen in the UK, so my project might have a few weeks delay while the boat from china makes its way over. i did however find this while digging, its about as minimal as an LCD can get

http://www.tinylcd.com/tiny149/product.php?id_product=22

im just waiting to hear if they will post to the UK, and what chip the display uses

senkun

@moosepr

I'd be interested to know what chip that uses too. The safest bet is of course the 2.8" version of your current 2.2" tft, looks like the same chinese manufacturer, uses the same ILI9341 as well should be a straight drop in.

alt text

moosepr

@senkun

yeah that by backup plan. although i think i may have an issue with the connectors being on the ends of the pcb. The screen edges are actually quite close to the buttons on the GBA. and adding the extra bulk for the brains of the screen that sits on one end, plus the pcb, might just take me too far.

I did ponder geting a custom pcb knocked up that was just the bare minimum for the screen to be used with SPI but have no idea where to start on that one!

moosepr

DAMIT!

Hello

The 2.8 LCD selected by you is not supported in fbtft.
If you want us to do PCB similar to your selection than we can offer you 2 options
100usd development charges
Or
Moq. 25 quantity
One more economical option is we can supply raspberry pi LCD without 40 pin header and than you do the wiring on the gpio header pads
Regards
Tinylcd

moosepr

Right!! i have a plan. I have been doing some digging and the ili9341 screens are actually all the same!! there are 2 variations, the larger have touch, and the smaller dont, the first 14 pins are the same regardless of the presence of touch. So all i need to do, is buy a naked 2.8" screen, and unsolder the 2.2" screen i currently have, and transplant the 2.8" screen on top!! that way the pcb is actually the same size, if not smaller than the screen, and there is more space to play with!!

now to wait for the good ship chinapost :D

Parzival

@moosepr this is so cool. where do you get the controllers/buttons from. I would like to build my own.

moosepr

@Parzival i did some hunting, didint want the usual 'clicky' tactile switches that are commonly used. I found a guy on ebay that sells all kinds of switches for the repair of keyfobs and the like

http://www.ebay.co.uk/itm/321411385630

the ones i got are the OMTEN D3. They are really nice, will be great behind some actual buttons, will give that retro feel of the rubber domes

thedudester80

That is a cool portable. I like the battery body idea. Must be really thin and light. Good work .

moosepr

Yeah it's just a shade thicker than a sharpie, and only 105 grams, so it's pretty skinny

senkun

@moosepr said in Yet Another Pi Zero Portable!!:

Right!! i have a plan. I have been doing some digging and the ili9341 screens are actually all the same!! there are 2 variations, the larger have touch, and the smaller dont, the first 14 pins are the same regardless of the presence of touch. So all i need to do, is buy a naked 2.8" screen, and unsolder the 2.2" screen i currently have, and transplant the 2.8" screen on top!! that way the pcb is actually the same size, if not smaller than the screen, and there is more space to play with!!

now to wait for the good ship chinapost :D

hey. Just wondering how's it going with your project? Did you get the the transplant done? And, what are you using for audio? Just noticed that you have no audio out in your build.

moosepr

@senkun

Hey man

Well I technically have all the bits, just need to iron out a few bits.

My plan with transplanting a 2.8 screen onto a 2.2 board didn't work. The distance from solder connector to screen edge is the same for all screens, so it gave me no benefit. I'm just trying to knock up a little PCB that will allow me to connect the screen with minimal board.

As for the sound, I'm planning on using an adafruit digital audio board https://www.adafruit.com/products/3006 which will give me mono sound for the speaker, or maybe even switchable to the headphones. That would then leave me with a hole where the volume knob should be.

The problem I have now, is once I have got my PCB designed it's going to be another 2 weeks at least. Although I will end up with some spares I could distribute.