Hi together,

i want to use a D4R-II together with APM2, PPM and RSSI are no problem. What i want to connect as well is 

the serial port of RX and APM2 to send compressed GPS information over the FrSky data downlink to my antenna tracker. in principle i have that working, currently with an arduino pro mini evaluating an attached GPS sensor, compressing the GPS data and sending it over the downlink. So tweaking arducopters software to do that as well will be no big deal. I use NewSoftSerial with the arduino as it provides the inverted TTL signal, that is expected from the FrSky RX.

Question now is:

1) Can FastSerial in Arducopter 2.6 somehow be used for generating an INVERTED TTL signal?

2) Which Pins/Port should i use on the APM2 to connect the FrSky RX serial port?



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Jerry, First test release is already on our repository. Download that, test it and let me know. 

It already supports following messages:

- Temperature

- Accels X, Y, Z

- Altitude

- Groundspeed

- Lat/Lon

- Running time

Get latest software from http://code.google.com/p/arducodes/downloads/list 

Just connect jD-IOBoard pin D5 to your receiver pin RX and data will start to flow.

There are still some minor issues with protocol feed but in generally it works just fine. Let me know how it works for you. 


I'll order the JD-IOboard tonight!     I'm looking forward to testing it.

hi jani, i have bought a jdrones ioboard for arducopter LEDs. can u pls tell what type of board to select when using arduino022 IDE compiler. it has a choice of 4 types of arduino 328. also whcih arduino code to use for the LED to glow without any I2C input.


    I have an APM 2.0 board.  I connect the JD-IOboard RX pin to the mavlink tx port on the APM  right?

Is it possible to connect this board to the APM 2.0 I2C bus while utilizing the RX/TX pins for MAVLINK/FrSky conversion ? I would like to access sensors on the other I/O pins, or possibly 

drive an array of LEDSs

Ravi, it's Arduino mini pro that you need to use. There are several demo sketches in our repository that you can use. One is ...._PWMFlasher

Jetty, sure it's possible to connect I2C but currently none of the APM2 softwares support I2C commands. If you want I2C to work you need to modify software for it.


You said:

"i want to use a D4R-II together with APM2, PPM and RSSI are no problem."

Please, can you tell me how to put the PWM RSSI signal of the d4fr into the apm2, wich normally expects an analog rssi signal?

So long

Kraut Rob

Hi this is exactly what I have been looking for. Do you any support docs or thread to review? I am very interested in persuing this further with your ioboard.



Pino it really depends on what you want to do. There are no ready made software for I2C connection but those are fairly easy to add. But again as I have no ideas what you plan so it will be a bit difficult to help

What I am trying to do, is leverage my FrSky Receiver DR8-XP or DR8II-Plus on the Quad-Copter to send Telemetry Data to the GCS with MavLink Data.  This could be a potential way of eliminating the need for Xbee or 3DR Data Modems.  If it is not possible, then it is pointless to have the Telemetry Modules to me as I don't want to see them on the Radio LCD, I would much rather see them in the GCS or on the OSD.  Sorry for all the acronyms.  ;-)

Thanks for your prompt replay btw.

Kind Regards, 

Pino Agostino

You posted awhile ago, but still to follow up, you need an RC filter plus voltage divider for PWM RSSI to analog. See this link :


I just ordered a couple IOBoards so I can send telemetry to the FRSky Rx, and see it on my 9XR transmitter. I also plan to split out the serial port on the DJT and feed it into an antenna tracker. 

I am excited to be able to have antenna tracking, telemetry on my transmitter and not run a 3rd RF link for telemetry. I think this is going to be a very powerful combination.

One question though, one of the comments on this posts says "Just connect jD-IOBoard pin D5 to your receiver pin RX and data will start to flow.", but all the docs for the FrSky telemetry Rx's say that the "streaming data port" are RS232 level (and not TTL). Doesn't this imply we need a MAX232 between the IOBoard and the FrSky RX?

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