Use a Raspberry Pi to Build a Functional Borderlands Echo Device - Hackster.io
Borderlands 3 ECHO Device Messenger Bag - Numskull
ECHO Device Borderlands 3 Blueprint | Etsy
Borderlands Raspberry Pi : 9 Steps (with Pictures) - Instructables
At the beginning of Borderlands 3, Claptrap says that the original ECHO-2 communicators were recalled and rebranded as grenades due to spontaneously exploding. Sure enough, the ECHO-2 can be found and equipped