Most of the activity is not being generated by Americans or in America. Lots are being started in India, Dubai and China. Even the ones based out of the US or Singapore spend most of their time in Shenzen.
In the US, I routinely see robotics and Healthcare hardware startups in Boston or San Diego, pseudo attached to the local university. No surprise that irobot and Boston dynamics are based out of Boston.
There are tons of small companies making hardware for oil & gas applications, but you'll mostly find them in areas where their customers are located (e.g. Texas, Alberta) and/or LCOL cities where you can find cheap real estate. This also applies to other industries like agriculture and automotive.
These aren't "sexy" companies so you don't hear much about them, but I'd wager that if you add them up, they'd outnumber the number of hardware startups in NYC and the Bay Area.
In my experience, they normally get started and funded by local people in their industry and they sell back to local customers (at least initially) from their network, so there's very little in the way of advertising, especially at a national level. Also, they often hire from their network for early positions and local colleges/universities as they grow, so you might not even see them on job boards.
If you're looking for companies that are a bit more established, you could try industry trade shows.
Agree. Lived in SG for 14 years, worked for hardware startups for 8 of those. There really isn't much going on HW wise.
My experience has been that if you work with the government on a project, as if by magic, ST Engineering comes up with a competing product within 1-2 years.