Finally settled on an Arduino design for the shrimp version of my series.
This is pretty much the version I am going to use.
Also noticed that the driver version of the FTDI USB to TTL adapter I got matters, I had a newer version and it worked only with one (seemed newer) adapter I had. But the rest all were failing. Then I downgraded the driver and it worked.
Gonna build a bunch of these shrimps for a project I have at the house.
For now, pushups and situps.