This reads to me as "I am not debating my right to exist [as a trans person or trans supporter]. I'm ready to defend myself and my allies if need be, to whatever extent is necessary. Back off or else."
So it comes across as a call to be ready to fight back, which would mean that if you're comfortable owning a gun or another weapon (or more comfortable owning a gun than not within the context of the current sociopolitical climate), it would be wise to have one on hand. I don't take it as a literal call to arms, it's more like an alternate, more direct/specific take on the Gadsden Flag. Not overtly hostile, but a clear warning that aggression will be responded to with an appropriate measure of self defense.
I'd also like to hear what your idea is. I don't know of a platform to solicit someone building your device at a price you'll be wanting to pay, but there are forums to help you learn how to do it yourself if you're motivated enough.
If it's cool enough to pique interest, you could try posting the concept in an electronics community and seeing if anyone's interested in the challenge, or an ideas community and just floating it for people to choose to run with.
It's also possible the device already exists and someone can suggest an easy option for you