
Sorry it's my mistake I wasn't There is no confusion. Now I would like to know your opinions and advices. I think I can use the 5V from the USB and use it for every Arduino/shield but I’m not sure. Not the Rx from the Uno and the Tx from the Leonardo. Only the TX from the Uno and the Rx from the two Leonardo will be use. I need also an optocoupler and a switch to ensure that only one Leonardo will have access to the data from the Uno at a time. I can’t use I☬ because it would be hard to demonstrate that data goes only in one way. I will use a serial transmission (TX and RX and the Easy Transfer Arduino Library from Bill Porter). The problem with this solution is special keys which are not taken into account. I use Leonardo Arduino in order to emulate Keyboard and Mouse using the HID library. I know it can be done by a cheaper Arduino but I want to reuse my hardware and the Uno is really helpful for many projects. I chose the Arduino Uno because I need an SPI Master to collect data from the Host USB. The shield will communicate to an Arduino Uno using the SPI. I want to use the Host USB shield rev 2.0.

The default serial port communication baud rate is 9600bps, which supports multiple serial communication formats and various common baud rate settings.Support 12Mbps full-speed USB transmission, compatible with USB V2.0.Through the provided host computer software, users can also configure the chip’s VID, PID, and various character string descriptors by themselves. It can receive the data (such as ASCII code) sent by the serial port, and according to the HID keyboard device specification, package the data into a standard keyboard code value and upload it to the computer through the USB port. It is suitable for one-way data transmission. This module is a serial port to HID device, which is recognized as a standard USB HID keyboard device on the computer. Proximity / TOF / Ultrasonic / PIR / Microwave.

