At-home portable ultrasound machine?

Sarah
Hello ladies, It's my first viable pregnancy, I'm 16 weeks, had several early-stage miscarriages and tend to worry a lot. Everything is new to me, I've mever gotten this far, I don't have anyone to talk to, and I'm very sensitive to every little physical sensation.
I was wondering if any of you have at-home portable ultrasound machines, if it's something safe, if it could reassure me in-between my ob-gyn consultations and if so, if anyone could recommend brands and models.
I've seen on the Internet that some machines allow you to hear the baby's heart, or some could even show you imagery on a screen or your smartphone.
But I don't know if it's authorized to have one, if it's safe, or if they are even commercialized to the public.