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The ArduCopter & ArduPilot Mega telemetry kit utilizes the Xbee Pro 2.4 GHz 63mw modules; this is the kit for use in the UK, EU and other parts of the world where the 900 MHz Xbee’s can’t be used due to mobile phones using the same frequency. 

This telemetry kit supports two way communication with the mission waypoint read and write functions in both Michael Oborne's Mission planner and HappyKillmore’s GCS on both the latest APM and ACM codes. This means no more USB cables & landings to connect the ArduPilot to a laptop in the field, you are able to view live telemetry data as your airframe progress through the mission, you can load a new mission on the fly while your UAV circles above you and execute that new mission without having to land! The range of operation has been tested out to half a mile with no loss in connection, connection has been found to drop off at 3/4 of a mile.

Included in the kit are all the items you need to have a fully functioning telemetry system:

• 2 x Xbee Pro’s series 1 (1 x whip antenna 1 x RPSMA).
• Ground and airframe adaptor boards (2 x XteamBee's).
• Antenna (RPSMA High gain 4.9 dBi).
• Connecting cables for both the GCS and airframe.  

The kits is available two forms:

Either as a pre soldered, fully programmed and tested kit, so they are completely plug and play or in a self built kit, for those of you who like to build your own. The kits are now in stock at www.buildyourowndrone.co.uk

The 2.4Ghz Pro series 2 Xbees (firmware XBP24-ZB, XBP24-B) do not work with the DIY Drones Xtreme Bee boards. Please use Sparkfun Xbee explorer boards.

Instructions:

Build the Xtream Bee’s:

The XtreamBee boards need to be built, this involves some soldering and is not complicated if you are experienced with soldering, however a word of warning here, when soldering the female headers, don’t use too much solder! The male pins of the Xbee modules will not fit into the female headers if any excess solder runs down inside the holes on the PCB, it will fill the female headers with solder, this is not good!

Down Load Here:

When you have changed the rate on the first board, remove the first Xtream Bee and switch over with the other, program the second one in the same way and to the same rate as the first.

On the APM you will see that there is a total of four connection ports marked "Teleport", (if you don't have the male pins to solder to the teleport for fitting the telemetry cable they can be found here) which will need to be connected to the airframe part of the telemetry kit. There are two pins for the power and two for the communication. Once again if you look at the XtreamBee you will see there is a “5v+”, “GND”, “In” and “OUT”. With the supplied APM telemetry cable you will find one end has 4 connections and the other has 5, the 4 goes onto the APM and 5 onto the XtreamBee, match the two ends to the corresponding pins and the APM is ready to send telemetry data to the GCS.

How to get the data:

To start using the telemetry, power the APM first which will power the airframe Xbee, power the GCS Xbee second, then load the Mission Planner or HK’s GCS select the correct comport and speed (57600) and click connect. You will now have your telemetry up and running!

Always select disconnect in the GCS before removing power from either of the units, I have found that on odd occasions if you just unplug one unit / switch the power off without disconnecting in the GCS you can lock a unit, this is easy to solve by reprogramming the XBee again, but to avoid it reverse the connection process.

Tests:

Use of 2.4 GHz Radio and Telemetry together:

This kit has been tested both in the field and in a lab environment to check for any clashes or interference between the RX/TX of the radio equipment operating on the same frequency as the Xbee’s, no conflicts have been found to exist.

The Xbee units on power up look at the frequencies available in the channel they have assigned, they will then select the one which has the least amount of noise, this is called DSSS in the world of Xbee’s, the DSSS operates in a very similar way to that of the 2.4 GHz radios with frequency hopping, which means we can fly more than one aircraft at a time and still use the same 2.4 GHz band as the pilot standing right next to us.

The field tests conducted were first with the radio on “range Check” which is a very low power setting, the Xbee was set to full power and placed on top of the RX and APM, the TX was taken to the minimum recommended distance and some way beyond, at which point there was still a solid lock and smooth operation of all the connected servos.

The radio I used throughout all of the field testing was a Futaba T7C, I have also released three full test kits to customers to try with additional radio equipment, all non Futaba, some of the radios tested were $60 specials while others were top end systems, all tests conducted have proven to be successful with no loss in control at any time and easy to use telemetry from the box.

While no concerns or issues have been identified with the telemetry kit and the radio systems when tested in the field or lab, it's highly recommend that a “range check” be carried out before committing to flight, if you can maintain a solid RX / TX lock at lowered powers on the ground beyond the minimum distance recommended then flight should not be an issue.

Regards

Martin

www.buildyourowndrone.co.uk