How to send a key only on double-tap?

Question

I know I can use

F1::Return

to disable the F1 key. But I would like to be able to still use it by simply double-tapping. However, when I try

$F1::
if (A_PriorHotkey <> F1 or A_TimeSincePriorHotkey > 400) {
    KeyWait, F1
    Return
}
Send, {F1}

(based on this post), the first press of F1 passes through while all following ones (including double-taps) are completely ignored.

Answer 1

Check your quotation marks...

$F1::
if (A_PriorHotkey <> "$F1" or A_TimeSincePriorHotkey > 400) {
    KeyWait, F1
    Return
}
Send, {F1}