FAQ

Q.: What is the default video channel?

A.: Boscam A, channel 1. You can change it from CLI: “set vtx_channel = X”. There are 40 channels (0…39) where 0-7 are Boscam A band channels, 8-15 Boscam B channels, 16-23 Boscam E channels, 24-31 Fatshark channels, 32-39 Raceband channels.


Q.: Does USB provide power to VTX?

A.: No, USB provides power for controller and the serial port +5v pins only. OSD and VTX require external +5v @1A minimum. We highly recommend to use the Pololu 1A BEC (https://www.pololu.com/product/2831).


Q.: When I upload an OSD font – nothing changes.

A.: Since USB doesn’t provide power to OSD chip, you should connect external +5v BEC first and then connect the board to USB. The latest Betaflight configurator (1.6) supports OSD configuration via drag and drop.


Q.: Where can I download the latest Betaflight firmware?

A.: The SIRINFPV target is already in the Betaflight master branch. So officially you’ll be able to download Betaflight firmware when 3.0.0 is released. For now you can either build the hex from the sourcecode yourself or download it from our support page (http://sirinfpv.com/support/).


Q.: Is the
Blackbox recording through UART or direct to the microSD card?  

A.: The microSD Blackbox is connected directly to CPU through SPI (no dedicated UART)


Q.: What is the mW rating of the VTX? 

A.: Installed module rated for 200mW, you can select 25mW or 200mW from OSD menu or via CLI command (see support page for all CLI commands (http://sirinfpv.com/support/).


Q.: What firmware do you use for the OSD?

A.: There is no separate OSD firmware, The OSD is integrated in the Betaflight firmware and connected directly to CPU through SPI in hardware. This is a new feature we added into Betaflight (already in the master branch).


Q.: Does the board use a VCP for USB or dedicated UART?  

A.: VCP + 3 totally free hardware UART ports.


Q.: What is the voltage range of the board?  5v only?  

A.: 5v only and the board takes around 500-600mA (including VTX and OSD) but we recommend to have at least 1A power supply from a high quality BEC like this one: https://www.pololu.com/product/2831.


Q.: What target is this for Betaflight?  Do you guys provide a custom compiled hex file?

A.: TARGET=SIRINFPV
The SIRINFPV target is already in the Betaflight master branch. So officially you’ll be able to download Betaflight firmware when 3.0.0 is released. For now you can either build the hex from sources yourself or download it from our support page (http://sirinfpv.com/support/).


Q.: Looks nice, but you couldn’t have squeezed a 5v regulator on there?

A.: Regarding the BEC issue – other boards in the market with BEC integrated do not have the need to feed VTX nor OSD.
These BECs have much less stress and work quite well. In our case, we need to provide at least 1A to have enough juice and some wiggle room for all the on-board components (which take about 500mA) plus cam and RX.
A 1A BEC needs a much bigger capacitor and inductor. We have trouble finding the physical space for it – esp. as we have to watch out for interference with other onboard components.
Evgeny (Savaga) was actually able to get a 450mA BEC working , but that is just not enough air for our trumpet.