working example for grabbing USB HID device

experiment/production/PIU-Notes.md

@@ -177,6 +177,57 @@ for device in dev:
 
 The above has to be played around with but it looks like the seeds are there.
 
+---
+
+If you don't care about capturing multiple devices at once (within a single program), the following does an active poll:
+
+```
+#!/usr/bin/python3
+
+import os, sys, evdev, asyncio, os.path
+from evdev import InputDevice, categorize, ecodes
+
+dev_init = False
+dev = { }
+
+HID_NAME = 'HID c216:0180'
+
+evfns_n = 13
+evfns_bd = "/dev/input/"
+evfns = [ ]
+
+for x in range(evfns_n):
+  fn = evfns_bd + "event" + str(x)
+  if (os.path.exists(fn)):
+    evfns.append(fn)
+
+for evfn in evfns:
+  _dev = evdev.InputDevice(evfn)
+  print("device:", _dev.name)
+  if _dev.name == HID_NAME:
+    dev_init = True
+    dev = _dev
+    break
+
+if not dev_init:
+  print("could not find device, exiting")
+  sys.exit(0)
+
+print(dev)
+print(dev.capabilities())
+print(dev.capabilities(verbose=True))
+
+dev.grab()
+
+for event in dev.read_loop():
+  if event.type == ecodes.EV_KEY:
+    print(categorize(event))
+
+```
+
+Note that the `HID_NAME` is specific to the USB magstripe reader I had on hand.
+Multiple of the same could be attached and would need to be differentiated by thei `/dev/input/event*` endpoints.
+
 
 References
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