[1arity]

Step 1. Walk into a University.

Step 2. Enter the mathematics department.

Step 3. Talk to anyone you see, especially anyone in front of a blackboard writing equations, and ask them to Try your keyboard.

Forget product hunt. Forget online.

Hit the streets!

Rinse and repeat. Also try : Physics, Statistics, Biology, Chemistry ( avoid CompSci since there will be too many time wasting questions from "app experts" and people who want to "help you out". Ignore. )

You will have so much info by the end of this. Take a friend, and video or tape record what you can. At the very least, have your friend take notes. Deconstruct at the end of the day. Rinse and repeat.

[morey]

I think he got a good point and if you are talking in person you can see the reaction to your product "live" and really capture the experience of your tester.

[Robby2023]

That's it, just go and talk with your potential customers.