So the pi zero is cool, retro gaming is cool, im really not cool, but i thought ‘what the hell!!’
Im not overly fond of ‘rats nest’ wires, and i have a bit of an obsession with making things as small as possible, so this is what i came up with.
tis just an ili9341 screen, a pi zero, 2 navi switches (5 way), and a battery (with charge/protect circuit)
using the notro’s fbtft driver, tasanakorn’s fbcp code to get the screen to display, and adafruit’s retrogame code to work the buttons
The eagle eyed among you might spot there is no ‘boost’ circuit!!!
The pi zero is actually quite tolerant, you dont actually need to feed it the full 5v to make it work. The main core of the pi runs on lower voltages, so the majority of it will happily run as low as 3v (i have heard it will run lower, but li-po protection kicks in before we get there), the only real need for the 5v on the pi is USB peripherals, which most will be ok with 3v too!!
Therefore the battery (4.2v-3v) is piped straight into the 5v line on the pi, cutting a boost circuit out of the mix, keeping the power usage below 250mah
So all the playing with batteries, and i had yet to test the actual battery i had intended in the first place. My first ever project was run from a 2500mah li-po, which yielded a 10 hour runtime, however was rather large.
So i tried what i thought was a 400mah drone battery, which size wise is smaller than the 2xAA battery holder. These ‘pouch’ cells come in varoius shapes and sizes, and a bit of hunting can find something perfectly sized
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