diff --git a/pins.go b/pins.go
new file mode 100644
index 0000000..a7662cb
--- /dev/null
+++ b/pins.go
@@ -0,0 +1,9 @@
+package drivers
+
+// PinInput is hardware abstraction for a pin which receives a
+// digital signal and reads it (high or low voltage).
+type PinInput func() (level bool)
+
+// PinOutput is hardware abstraction for a pin which outputs a
+// digital signal (high or low voltage).
+type PinOutput func(level bool)