WHID Injector was born from the need for cheap and dedicated hardware that could be remotely controlled in order to conduct HID attacks (i.e. over WiFi). It is a cheap but reliable piece of hardware designed to fulfill Pentesters needs related to HID Attacks, during their engagements. The core of WHID is mainly an Atmega 32u4 (commonly used in many Arduino boards) and an ESP-12s (which provides the WiFi capabilities and is commonly used in IoT projects). Nonetheless, during the last months, a new hardware was under R&D (i.e. WHID Elite). It replaces the Wi-Fi capabilities with a 2G baseband, which gives unlimited operational range. This cute piece of hardware is perfect to be concealed into USB gadgets and used during engagements to get remote shell over an air-gapped environment. In practice, is the "wet dream" of any ICS Red Teamer out there.
As you know, both R&D processes that brought WHID Injector and WHID Elite to life, were not backed by any crowd-sourcing fund and the sale of these devices are not going in any form to me (i.e. Luca). I am just doing this as hobby, fun and (most importantly) I believe in giving back something to the InfoSec community without making any profit out of it.