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Homebrew tiny pi clone

Posted: Mon Jun 04, 2018 7:35 am
by doro44
Hi guys,

another homebrew project - a tiny pi clone :)
I designed the board by my self, the board is singlesided for easy home etching. I did use slightly bigger display 1.8" 128x160 px and bigger directional button.
IMG_0510.JPG
IMG_0510.JPG (114.14 KiB) Viewed 7864 times
IMG_0511.JPG
IMG_0511.JPG (133.61 KiB) Viewed 7864 times
and here is the bare pcb:
IMG_0512.JPG
IMG_0512.JPG (128.68 KiB) Viewed 7864 times
If someone would be interested I can share the PCB design and list of components used (all aliexpress)...

Re: Homebrew tiny pi clone

Posted: Mon Jun 04, 2018 7:43 am
by klotzii
Yeah, I´m interested!
Please share your parts list and the PCB files!

Re: Homebrew tiny pi clone

Posted: Mon Jun 04, 2018 12:10 pm
by doro44
I ll just put here everything:

display: https://www.aliexpress.com/item/1pcs-1- ... 4c4dDehBMr
Joystick: https://www.aliexpress.com/item/5-pcs-5 ... 4c4dUIH3yl
Big buttons: https://www.aliexpress.com/item/20PCS-L ... 4c4dUIH3yl
Small buttons: https://www.aliexpress.com/item/100PCS- ... autifyAB=0
Switch: https://www.aliexpress.com/item/50Pcs-M ... autifyAB=0
Power: I have taken out of the mini powerbank that was powered by single 18650 cell
Battery: similar to this: https://www.aliexpress.com/item/Gaoneng ... autifyAB=0

I have created the PCB in easyeda online, and you can download the cb here: http://dorica.sk/downloads/
Just download, change the extension to json and load to easyeda...

For display, I am using fbtft st7735r driver, just enable dtparam=spi-on in config.txt, follow standard procedure to install fbtft and add add following line to your fbtft.conf file:
options fbtft_device custom name=fb_st7735r gpios=reset:25,dc:24 speed=16000000 width=128 height=160 rotate=0 bgr=0 fps=60

For buttons, I have used this guide: https://sudomod.com/forum/viewtopic.php?t=57

Re: Homebrew tiny pi clone

Posted: Mon Jun 04, 2018 1:38 pm
by angelgrant
I'm interested in it! Great thing

Re: Homebrew tiny pi clone

Posted: Mon Jun 04, 2018 2:08 pm
by epicpwn
Nice work! Any videos of this in action?

Re: Homebrew tiny pi clone

Posted: Tue Jun 05, 2018 2:33 am
by moosepr
nicely done!! You might be able to get that speed value up a bit to help make the screen run faster. try this

speed=40000000

:)

Re: Homebrew tiny pi clone

Posted: Tue Jun 05, 2018 12:54 pm
by doro44
I need to mention one thing - it appears I did use too big resitor (150 ohm) for the display backlight. I am going to try lower resitance to make sure the backlight is not so dim:
IMG_0516.JPG
IMG_0516.JPG (94.32 KiB) Viewed 7785 times
I am going to try to put one more in paralel, it should lower the resitance to half.

Re: Homebrew tiny pi clone

Posted: Tue Jun 05, 2018 12:55 pm
by doro44
Also, what retropie theme would you guys recommend for this small screen?

Re: Homebrew tiny pi clone

Posted: Tue Jun 05, 2018 1:27 pm
by Helder
Use a 3.6ohm resistor for proper backlight voltage.

Re: Homebrew tiny pi clone

Posted: Tue Jun 05, 2018 4:15 pm
by Gizard
When I click the link on your website to download your PCB, I just get a very long line of code.