First CircuitPython Program

Published on 2017-07-19 in PewPew FeatherWing.

Today I found one more bi-color matrix that I have left (more of them are ordered for the next version), and used it to assemble a second PewPew Lite. I’m really happy with how it works, and I’m considering switching entirely to the Lite version — four colors are enough for most games, and really simplify things.

However, this time I decided to make it as flat as possible, so I used the 3mm female pin headers on the Feather board, and shortened the male headers. The effect:

Unfortunately it can’t get any flatter, because of the battery plug and the chip on the underside of the shield. But one centimeter is still quite good. I wonder if I can find a LiPo battery that would fit in the space between the boards – but more likely I will just stick the battery on the bottom.

I also wrote the driver for the CircuitPython (used MicroPython before that), and a simple drawing program:

import pewpew
import time
pewpew.brightness(0)
pewpew.show()
x = 3
y = 3
color = 1
hold = 0
blink = False
hold_keys = (pewpew.K_UP | pewpew.K_DOWN | pewpew.K_LEFT | pewpew.K_RIGHT |
             pewpew.K_X)
while True:
    keys = pewpew.keys()
    if not keys & hold_keys:
        hold = 0
    if keys & pewpew.K_UP:
        y = max(0, y - 1)
    elif keys & pewpew.K_DOWN:
        y = min(7, y + 1)
    if keys & pewpew.K_LEFT:
        x = max(0, x - 1)
    elif keys & pewpew.K_RIGHT:
        x = min(7, x + 1)
    back = pewpew.pixel(x, y)
    if keys & pewpew.K_O:
        back = color
    if keys & pewpew.K_X:
        color = (color + 1) % 4
    if blink:
        pewpew.pixel(x, y, color)
    elif back == color:
        pewpew.pixel(x, y, (color + 1) % 4)
    else:
        pewpew.pixel(x, y, back)
    blink = not blink
    pewpew.show()
    pewpew.pixel(x, y, back)
    while pewpew.keys() & hold_keys and hold < 15:
        time.sleep(0.025)
        hold += 1
    time.sleep(0.125)

As you can see, most of the code is dedicated to handling keys, including the repeating when a key is held down. The library is very bare bones for now, but I like the simplicity. I will probably need to add a function to display text, and some functions for scrolling around.