3DR Telemetry Radio (clone)

Hello I was wondering if there is a stripped down C library that will allow me to talk to the 3DR telemetry radio with out one of the devices being connected to APM or pixhawk?

I’ve been able to use the HAYES AT modem commands to talk to both the USB and UART telemetry sticks to read the info from the “modem”.

ATI gives:
SiK 1.9 on HM-TRP

If I set SD4: to mavlink = 0
will it just allow me to use the telemetry stick like it’s a normal uart and ignore the mavlink data structure?

Is there a basic APM/Pixhawk handshake that needs to be emulated to get the thing to send mavlink formated packets? Or will it automatically send mavlink formatted packets?

All I want to do is send still images and telemetry to a base station. I got a really god deal on a Matrice 100. Unfortunately they don’t seem to want you to be able to utilize their UDP video packet bandwidth for anything. They have an onboard Uart but it will only allow 8kbs data rates to a base station hooked to the receiver via usb. Obviously that is unacceptable.

I was thinking since I need to read data from the DJI N1 flight controller and send and receive data from the 3dr telemetry stick, that I could use a psoc 5lp mico controller for data arbitration between the DJI, 3DR and a raspberry pi zero which will be grabbing images from a flir lepton thermal camera.

Anybody here have any idea if there’s a quick dirty route to using these 3dr telemetry radios???



Yes, it will work just as any other transparent link, no init needed.
If you’re not using mavlink, disabling mavlink frame optimization would be a good thing.

Yeah I ended up figuring it out.
Although it doesn’t seem to matter whether or not I turn off the mavlink framing.
It just sends and receives whatever bytes I send over the UART.

I currently have formatted the data I’m sending to “Mavlink v2”
Which if using the signature will be 25 - 280 bytes per packet depending on data payload.

Is there something else the telemetry is looking for with regards to packet framing?

I suppose 25 byte overhead isn’t bad.
This “ReadyToSky” radio claims to be 500mW.
I’m not sure if there’s a way to verify that. There’s certainly no way to turn up the power to 27dB with the AT commands.

Has anyone here tried pushing the data rates on these things? I’ve read that the radios are adaptive. It is claimed that the data rate can be as fast as 250kBaud.

To get that much over the air what should I set my uart internal data rates to? they claim they operate up to ~920kBaud.

Should I set my internal baud rate to double the maximum transmission rate?
Is there a reason to operate all the way at 920kBaud internally?

There’s no info on how big the buffer is on the uart. Is it possible to overflow the buffer on these things if the transmission data rate is to low?

Thanks for your help.