raspberry pi gpio input test script

NS.py

@@ -1,10 +1,14 @@
 # -*- coding: utf-8 -*-
 
-# [SCRAPEBOARD] is an arcade game in development by [@diskmem] & [@snakesandrews]
+# [SCRAPEBOARD] is an arcade game in development by [@diskmem] & [@snakesandrews].
 # 
 # It requires custom hardware to play but can be tested in keyboard mode without
 # the hardware. For more information on setting up and running the game, see 
 # README.md, or for the game in general, visit <https://scrape.nugget.fun/>.
+#
+# Full open source code is available at <https://git.nugget.fun/scrape/scrapeboard>.
+#
+# This is the main file containing all the pygame code.
 
 import argparse, pathlib, operator, subprocess, sys
 from random import randint, choice, random

gpio_test.py

@@ -0,0 +1,75 @@
+# [SCRAPEBOARD] is an arcade game in development by [@diskmem] & [@snakesandrews]
+#
+# It requires custom hardware to play but can be tested in keyboard mode without
+# the hardware. For more information on setting up and running the game, see 
+# README.md, or for the game in general, visit <https://scrape.nugget.fun/>.
+#
+# Full open source code is available at <https://git.nugget.fun/scrape/scrapeboard>.
+#
+# This is a utility script for testing if the GPIO interface of a Raspberry Pi is working
+# with the four input wires, which correspond to the four metal floor pads in the standard
+# Scrapeboard build.
+
+import time, itertools
+import RPi.GPIO as GPIO
+
+# These represent the game pads and the GPIO pins they're connected to
+LNW, LNE, LSE, LSW = range(4)
+pins = {
+    LNW: 17,
+    LNE: 27,
+    LSE: 22,
+    LSW: 23
+}
+
+def connection2(pin_a, pin_b):
+    """
+    Set `pin_a` to output a low signal, and set every other pin to pullup. If `pin_b` reads a low signal even though
+    it's set to pullup, that means `pin_a` is connected to it, so return `True`.
+
+    @param pin_a   Pin which will be set to output LOW
+    @param pin_b   Pin which will be read
+    @return        `True` if a low signal is sent from `pin_a` to `pin_b`, `False` otherwise
+    """
+    for pin_id, pin in pins.items():
+        if pin == pin_a:
+            # Set pin_a to output LOW
+            GPIO.setup(pin, GPIO.OUT)
+            GPIO.output(pin, GPIO.LOW)
+        else:
+            # Set all other pins to input pullup
+            GPIO.setup(pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
+
+    # pin_b can now be tested to see if if reads the LOW signal from pin_a
+    return GPIO.input(pin_b) == GPIO.LOW
+
+def connection(pin_a, pin_b):
+    """
+    Tests low signals connect from both A to B and from B to A
+
+    @param pin_a   Test if this pin is connected to `pin_b`
+    @param pin_b   Test if this pin is connected to `pin_a`
+    @return        `True` if `pin_a` and `pin_b` are connected, `False` otherwise
+    """
+    return connection2(pin_a, pin_b) and connection2(pin_b, pin_a)
+
+def connections():
+    """
+    Look at all six possible connections between the four pins and print a message if one is found connected.
+    """
+    for pin_id_a, pin_id_b in itertools.combinations(pins, 2):
+        if connection(pins[pin_id_a], pins[pin_id_b]):
+            print(f"{pin_id_a} ({pins[pin_id_a]}) <-> {pin_id_b} ({pins[pin_id_b]})")
+
+if __name__ == "__main__":
+    # Use GPIO numbering
+    GPIO.setmode(GPIO.BCM)
+
+    # Set all pins to pullup
+    for pin_id, pin in pins.items():
+        GPIO.setup(pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
+
+    while True:
+        # Try all connections once each frame
+        connections() 
+        time.sleep(0.1)