40+ Mile range!!! Arduino Mega Piggy-back all-in-one solution (sensors, control, telemetry, video)







THIS IS the BEST (imo) Telemetry module out there currently !!!




This is a radio module that's small, fast, inexpensive, powerful, US legal 900mhz (and others). It has adjustable power output, spread spectrum frequency hopping, encryption, and TONNNNSS of other features. Also, at only $70 a pop (from digikey.com), they are Very easy on the wallet! especially compared to the digi xtend radio that is near $200 per. ouch!


I have three of RFM's DNT900 radios, and am working on Arduino programming to set-up and control them. I am working with the friendly tech at RFM who supports their products, and we are discussing a few more details about the needs of the radio. I intend to post more as I get farther along, and create a code block that people can copy-paste into their program to utilize this fantastic radio.



It has been a month, and I have just recently set up the architecture and got communication between two radios. I have them set to 200kb/s RF over air, allowing for up to 1watt of transmission power.


Still to go - i need to set up radio access lists, add 128 bit encryption, and adjust baud rate.

oh, and clean up the code! messy



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found it - was expecting the info in datasheet but its in the guide. thanks.

sentence parsing is online, along with checksums.

As for the variable issue - atoi fixes it (whoops - forgot that one)


After confirming with a RFM tech, I learned that the radios automatically manage their power output. They will put out as much as they need - up to the max level you set (which is awesome).

of course you can manage it manually, but for this application its so much more convenient to let the DNT900 do it.


Now I need to get numbers with decimal points sent over the connection - im thinking long or floats..

I use the DNT900 in the Andromeda UAV. You can see the one on the Autopilot and the other on the Ground Station. These radios are great. If you've got any questions I might be able to answer them as I've spent a bit of time programming these things.

Thanks for the offer! I just got them up and running. I do notice programing them can be flakey, and i get bad data transmissions that screw up some of the sentences sent. maybe one loss per 5 seconds?


Have you noticed any issues like that?



by the way, im a big fan of your build. Everything looks so clean, and your website is really nice with great pictures!


OK so its been a while since ive updated - but ive been working on a few other secret ideas for this muhahaha

so far so good - should be a really new approach that no one on these forums has taken!



That aside - radios are 100% operational. Full variables for data, and parsing on both sides. Therefore you can spit control data at it, and it prints it on the other side...   at the same time the remote can be sending flight data and the base station can be monitoring stats.


I'm going back into my cave now...  lots to do with school etc, but i will continue progress on this project! hopefully get it all stuck to a PCB one day - which would mate to a mega, or something similar!


I just switched to Elec. Engineering at the U of I !!   ...agh, my true calling!

I have been dabbling in a little board design / layout. Currently, I have two piggyback boards made up. They plug in atop an arduino Mega.


One acts as the basestation

This has a DNT900 radio, a Maxim chip to allow for a special type of controller (more info later), 5volt (3 amp) and 3.3 volt power supplies. The 5volt PS has an input range from 7-40 volts, and replaces the arduino 5v ps. This allows for a single power supply to power all components, and be able to provide current in excess of the peak requirements of the radio and the controllers power bus. It also has a plug for status LED's if desired. It is the same size as the mega board. There's still room on the board for future additions


The other acts as the Remote.

This piggy-back module includes the remote DNT900 radio, plugs for 10 servos, plugs for status LED's, and external power plugs. It also has pin connections for Remzibi OSD, and CHRobotics Extended Kalman filtered CHR-6dm 9dof. I am extremely impressed with these two devices. Integrating them gives us filtered XYZ positional data, GPS information, on screen display, 3.3 power supply.  I have also added a SCP1000 for barometric and temperature readings. 


This board requires twin 5volt supplies, and a 12v. - I am trying to fit them into the PCB, but its tough. Also, switching buck controllers are noisy - so i need to make sure they wont interfere with other electronics.

- one 5v will power the board, sensors, radio, and video transmission radio.

- the other 5v is dedicated to powering the servos. They share a common ground - arduino will be able to switch on/off to save power if you are landed

- a 12v power supply will also be added for the camera - arduino will be able to switch on/off to save power

- power input will accept between 12 volts and 40 volts, for a variety of battery setups!




http://www.happykillmore.com/Software/Faq.asp REMZIBI OSD


http://www.chrobotics.com/index.php?main_page=product_info&prod... CHRobotics




i have a DNT900 but i can't establish the communication with it!

can you send me the shematic and sample code code used to configure it?



// byte VAR[] = {FB,LENGTH,TYPE,ARGUEMENTS}; // in hex

byte SET_BASE[] =  {0xFB,0x05,0x04,0x00,0x00,0x01,0x01}; // set as base

byte SET_RMOT[] =  {0xFB,0x05,0x04,0x00,0x00,0x01,0x00}; // set as remote

byte SAV_ONLY[] =  {0xFB,0x05,0x04,0xFF,0xFF,0x01,0x01}; // save

byte SAV_RSET[] =  {0xFB,0x05,0x04,0xFF,0xFF,0x01,0x02}; // save and reset


All the configuration information is in the PDF user manual - but these 4 should get you started!


make sure to read the PDF on the connections for the DNT900 board. And level-convert the 3.3v logic to 5 volt for things like 5volt arduino!


sorry, i don't have a schematic at this point. at least nothing on computer - and im away from home




BEST of luck! let me know if there's anything else i can do!

Thank you.

i read tha datasheet but can't understand how i connect some pin (like CFG, DTR ....).

i want just use RX and TX  to send data.... (i converted 5V to 3.3V like datasheet)

can you send me the pinout connection ?



it explains the purpose of the input pins, and their accepted input states. The CFG is only low when you want to configure the dnt900. else, high allows transparent communication


Focus on pins 18,19,20,21,24,30,31,32


pins 25 and 26 are great for LED status lights


i found the error (ouuufff), i don't connect the pin 30 to the ground.


Thank you for your help.

NICE glad it works! i think its better to tie it to an I/O so you can do flow control. haven't done it yet myself, though!


glad it works!


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